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宇宙ばなしがベースになっている書籍「やっぱり宇宙はすごい（SB新書）」は好評発売中！おかげさまで即重版！Audibleでも！Audibleの無料体験はこちらから！著書「マーケティングをAIで超効率化！ChatGPT APIビジネス活用入門（講談社）」好評発売中！もう1つのチャンネル「となりのデータ分析屋さん」はこちら！Spotify /Apple Podcast個人ホームページはこちら！Twitter（_ryo_astro)ジングル作成：モリグチさんfromワクワクラジオソース：
Please meet Dr Anya Nugent … she is amazing … and she has some beautiful stories for us … let's hear all about unbelievably powerful Gamma Ray bursts and their host galaxies from an amazing Harvard and Smithsonian astrophysicist who uses incredible observatories like CHANDRA, XMM-Newton, ALMA, CHIME, MEERKAT, the VLA and even our old friend Hubble … to reveal new understandings of how our universe works.
The United Kingdom's robust and ambitious space sector has many personalities. Each year at the Better Satellite World Awards Dinner in December in London, the SSPI UK Chapter recognizes one of them as the Satellite Personality of the Year. In this podcast, we hear from the 2024 honoree, Dr. David Parker FRAeS, Non-Executive Board Member of the UK Space Agency and Visiting Professor at the University of Southampton. This interview was originally broadcast as part of the Personalities of the Space & Satellite Industry podcast series, which aired before Dr. Parker was named the 2024 Satellite Personality of the Year. Dr. David Parker has led a distinguished thirty-five-year career in the space sector, spanning industry, UK government and the European Space Agency (ESA). Until June 2023, he served as ESA's Director of Space Exploration at ESTEC in the Netherlands, overseeing astronaut missions to the International Space Station, Europe's involvement in Artemis and pioneering projects like training an astronaut with a physical disability. Previously, he was the Chief Executive of the UK Space Agency (2013-2016), where he led Tim Peake's ISS mission and negotiated ESA's first UK center in Harwell. Starting in the UK space industry in 1990, he contributed to projects like XMM-Newton and ExoMars. Dr. Parker holds a degree in Aeronautics and Astronautics and a PhD from NASA Langley Research Center. He has received several accolades, including the Royal Aeronautical Society's Geoffrey Pardoe award. He currently works part-time at ESA, serves on the UK Space Agency Board and is a Visiting Professor at the University of Southampton.
Mars-missioner, prøver fra Månens bagside, en rumstation, hele to store satellit-konstellationer og massevis af raketopsendelser. Det er bare nogle af de mange rumaktiviteter, Kina har gang i. I denne episode retter vi teleskopet mod Kina, fordi der sker så voldsomt mange spændende ting derovre i disse år, der også påvirker rumaktiviteterne i resten af verden. Men vi har trods alt talt med en dansk rumekspert i Kina – nemlig Thomas Schumann, der i flere år var vært på Radio4-podcasten Den Nye Rumalder, og som i dag har sin egen rumpodcast, Schumanns Rumraket. Thomas er især interesseret i Kinas Chang'e rummissioner, og det er også et af de områder hvor Kina mest direkte ligger i konkurrence med USA. Og der er næppe tvivl om at det nye store rumræs står mellem netop de to nationer. Hør meget mere om det, når vi taler med Thomas – og så er der selvfølgelig også korte rumnyheder, denne gang blandt andet om gigantiske rumobjekter, supernovaer og nye ESA-projekter. Lyt med
大阪開催の竹中工務店イベント「たてものめがね まちめがね」壇します31歳になりました！誕生日プレゼント送りたい！って方は書籍「やっぱり宇宙はすごい」を買ってください。もう持ってる方は、2冊目3冊目を買ってくれると僕がヒット作家になれるという最高の誕生日プレゼントになります。https://amzn.to/3UAeSr9ほしい物リストhttps://www.amazon.jp/hz/wishlist/ls/3D944KX18YFUU?ref_=wl_share集英社連載最新回「2026年には水星からリアル配信が見られるかも？ 計画実施まで21年かかったJAXA「みお」の水星探査」 を公開しました！Youtubeチャンネルも更新中！Instagram（ryo_astro）個人ホームページはこちら！Twitter（_ryo_astro)もう1つのチャンネル「となりのデータ分析屋さん」はこちら！Spotify /Apple Podcastお便りコーナーはこちら！ジングル作成：モリグチさんfromワクワクラジオソースhttps://www.nasa.gov/general/exoplanets-need-to-be-prepared-for-extreme-space-weather-chandra-finds/
Planets around other stars need to be prepared for extreme weather conditions, according to a new study from NASA's Chandra X-ray Observatory and ESA's XMM-Newton that examined the effects of X-rays on potential planets around the most common type of stars.
Europas Röntgensatellit XMM-Newton beobachtet seit 25 Jahren das heiße energiereiche Universum, zum Beispiel die Umgebung Schwarzer Löcher und das Leuchten riesiger Galaxienhaufen. Sein Namenspatron Isaac Newton wirkte an etlichen Todesurteilen mit. Lorenzen, Dirk www.deutschlandfunk.de, Sternzeit
The United Kingdom's robust and ambitious space sector has many personalities. In this podcast series, we introduce you to three whom the UK Chapter of SSPI is considering for its prestigious Personality of the Year Award in 2024. One of these three finalists will be named the 2024 Satellite Personality of the Year live at the Better Satellite World Awards Dinner in London on 2 December. Click here to join us there! Each of the three finalists is a star who has made significant contribution to the UK and global satellite industry and whose career is a study of performance and excellence at the highest level. In the first episode, we learn a bit more about Dr. David Parker FRAeS, Non-Executive Board Member of the UK Space Agency and Visiting Professor at the University of Southampton. Dr. David Parker has led a distinguished thirty-five-year career in the space sector, spanning industry, UK government and the European Space Agency (ESA). Until June 2023, he served as ESA's Director of Space Exploration at ESTEC in the Netherlands, overseeing astronaut missions to the International Space Station, Europe's involvement in Artemis and pioneering projects like training an astronaut with a physical disability. Previously, he was the Chief Executive of the UK Space Agency (2013-2016), where he led Tim Peake's ISS mission and negotiated ESA's first UK center in Harwell. Starting in the UK space industry in 1990, he contributed to projects like XMM-Newton and ExoMars. Dr. Parker holds a degree in Aeronautics and Astronautics and a PhD from NASA Langley Research Center. He has received several accolades, including the Royal Aeronautical Society's Geoffrey Pardoe award. He currently works part-time at ESA, serves on the UK Space Agency Board and is a Visiting Professor at the University of Southampton.
Un telescopio a raggi X da manuale. Venticinque anni di onorato servizio senza mai disturbare, raccogliendo una mole di dati tale da non riuscire a usarli tutti. Lui è Xmm-Newton, un telescopio spaziale di proprietà congiunta fra Esa e Nasa. Tutto perfetto, tranne un piccolo incidente durato tre giorni nel 2008, nove anni dopo il lancio. E siccome noi di Houston non perdoniamo niente, ne parliamo con Paolo Ferri in questo episodio, con una pillola sull'astronomia X di Stefano Ettori. Musiche: “Contagion”, Scott Buckley; “Sneaky Snooper”, instrumental brother
A new study using NASA's Chandra and ESA's XMM-Newton reveals that the interiors of neutron stars may contain a type of ultra-dense matter not found anywhere else in the Universe.
A study with Chandra and XMM-Newton indicates which stars near our Sun could have habitable exoplanets around them based on whether they receive lethal radiation from the stars they orbit.
La tertulia semanal en la que repasamos las últimas noticias de la actualidad científica. En el episodio de hoy:Cara B:-Argumentos contra la presencia de atmósferas en Trappist-I (00:00)-La causa autoinmune del síndrome de Guillain-Barré (en algunos pacientes) (38:12)-El agujero negro de Markarian 817 observado por XMM-Newton and NuSTAR (1:05:02)-Enormes agujeros negros (que son pequeños puntos rojos) en 4
Astronomers using NASA's Chandra, ESA's XMM-Newton, and other telescopes have determined that a giant black hole has destroyed a large star and strewn its contents into space.
Une équipe d'astrophysiciens rapporte la mesure de la polarisation des rayons X de la brillante galaxie de Seyfert NGC 4151 pour en déduire la géométrie de sa source d'émission. Elle a été observée avec le télescope spatial Imaging X-ray Polarimetry Explorer (IXPE), et complétée par des observations simultanées de XMM-Newton et NuSTAR. L'étude est publiée dans les Monthly Notices of the Royal Astronomical Society.
Astronomers have captured a spectacular, ongoing collision between at least three galaxy clusters. Data from Chandra, XMM-Newton, and a trio of radio telescopes are helping astronomers sort out what is happening in this jumbled scene.
The Rapidly Spinning Intermediate-Mass Black Hole 3XMM J150052 0+015452 by Z. Cao et al. on Wednesday 30 November A star tidally disrupted by a black hole can form an accretion disc with a super-Eddington mass accretion rate; the X-ray emission produced by the inner disc provides constraints on the black hole mass $M_bullet$ and dimensionless spin parameter $a_bullet$. Previous studies have suggested that the $M_bullet$ responsible for the tidal disruption event 3XMM J150052.0+015452 (hereafter J150052) is $sim$10$^{5} M_{odot}$, in the intermediate black hole (IMBH) regime. Fitting multi-epoch XMM-Newton and Chandra X-ray spectra obtained after 2008 during the source's decade-long decay, with our latest slim accretion disc model gives $M_bullet = 2.0^{+1.0}_{-0.3}times10^{5} M_{odot}$ (at 68% confidence) and $a_bullet > 0.97$ (a 84.1% confidence lower limit). The spectra obtained between 2008-2014 are significantly harder than those after 2014, an evolution that can be well explained by including the effects of inverse-Comptonisation by a corona on the early-time spectra. The corona is present when the source accretion rate is super-Eddington, while there is no evidence for its effect in data obtained after 2014, when the mass accretion rate is around the Eddington-limit. Based on our spectral study, we infer that the corona is optically thick and warm ($kT_e=2.3^{+2.7}_{-0.8}$ keV). Our mass and spin measurements of J150052 confirm it as an IMBH and point to a rapid, near extremal, spin. These $M_bullet$ and $a_bullet$ values rule out both vector bosons and axions of masses $sim10^{-16}$ eV. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16936v1
Investigating the origin of optical and X-ray pulsations of the transitional millisecond pulsar PSR J1023+0038 by G. Illiano et al. on Friday 25 November PSR J1023+0038 is the first millisecond pulsar that was ever observed as an optical and UV pulsar. So far, it is the only optical transitional millisecond pulsar. The rotation- and accretion-powered emission mechanisms hardly individually explain the observed characteristics of optical pulsations. A synergistic model, combining these standard emission processes, was proposed to explain the origin of the X-ray/UV/optical pulsations. We study the phase lag between the pulses in the optical and X-ray bands to gain insight into the physical mechanisms that cause it. We performed a detailed timing analysis of simultaneous or quasi-simultaneous observations in the X-ray band, acquired with the XMM-Newton and NICER satellites, and in the optical band, with the fast photometers SiFAP2 (mounted at the 3.6 m Telescopio Nazionale Galileo) and Aqueye+ (mounted at the 1.8 m Copernicus Telescope). We estimated the time lag of the optical pulsation with respect to that in the X-rays by modeling the folded pulse profiles with two harmonic components. Optical pulses lag the X-ray pulses by $sim$ 150 $mu$s in observations acquired with instruments (NICER and Aqueye+) whose absolute timing uncertainty is much smaller than the measured lag. We also show that the phase lag between optical and X-ray pulsations lies in a limited range of values, $delta phi in$ (0 $-$ 0.15), which is maintained over timescales of about five years. This indicates that both pulsations originate from the same region, and it supports the hypothesis of a common emission mechanism. Our results are interpreted in the shock-driven mini pulsar nebula scenario. This scenario suggests that optical and X-ray pulses are produced by synchrotron emission from the shock that formed within a few light cylinder radii away ($sim$ 100 km) from the pulsar, where its striped wind encounters the accretion disk inflow. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12975v1
Taking a break: paused accretion in the symbiotic binary RT Cru by A. Pujol et al. on Friday 25 November Symbiotic binaries sometimes hide their symbiotic nature for significant periods of time. There is mounting observational evidence that in those symbiotics that are powered solely by accretion of red-giant's wind material onto a white dwarf, without any quasi-steady shell burning on the surface of the white dwarf, the characteristic emission lines in the optical spectrum can vanish, leaving the semblance of an isolated red giant spectrum. Here we present compelling evidence that this disappearance of optical emission lines from the spectrum of RT Cru during 2019 was due to a decrease in the accretion rate, which we derive by modeling the X-ray spectrum. This drop in accretion rate leads to a lower flux of ionizing photons and thus to faint/absent photoionization emission lines in the optical spectrum. We observed the white dwarf symbiotic RT Cru with XMM-Newton and Swift in X-rays and UV and collected ground-based optical spectra and photometry over the last 33 years. This long-term coverage shows that during most of the year 2019, the accretion rate onto the white dwarf was so low, $dot{M}= (3.2pm 0.06), times$10$^{-11}$ $M_{odot}$ yr$^{-1}$ (d/2.52 kpc)$^2$, that the historically detected hard X-ray emission almost vanished, the UV flux faded by roughly 5 magnitudes, the $U$, $B$ and $V$ flickering amplitude decreased, and the Balmer lines virtually disappeared from January through March 2019. Long-lasting low-accretion episodes as the one reported here may hamper the chances of RT Cru experiencing nova-type outburst despite the high-mass of the accreting white dwarf. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.13193v1
Investigating the origin of optical and X-ray pulsations of the transitional millisecond pulsar PSR J1023+0038 by G. Illiano et al. on Thursday 24 November PSR J1023+0038 is the first millisecond pulsar that was ever observed as an optical and UV pulsar. So far, it is the only optical transitional millisecond pulsar. The rotation- and accretion-powered emission mechanisms hardly individually explain the observed characteristics of optical pulsations. A synergistic model, combining these standard emission processes, was proposed to explain the origin of the X-ray/UV/optical pulsations. We study the phase lag between the pulses in the optical and X-ray bands to gain insight into the physical mechanisms that cause it. We performed a detailed timing analysis of simultaneous or quasi-simultaneous observations in the X-ray band, acquired with the XMM-Newton and NICER satellites, and in the optical band, with the fast photometers SiFAP2 (mounted at the 3.6 m Telescopio Nazionale Galileo) and Aqueye+ (mounted at the 1.8 m Copernicus Telescope). We estimated the time lag of the optical pulsation with respect to that in the X-rays by modeling the folded pulse profiles with two harmonic components. Optical pulses lag the X-ray pulses by $sim$ 150 $mu$s in observations acquired with instruments (NICER and Aqueye+) whose absolute timing uncertainty is much smaller than the measured lag. We also show that the phase lag between optical and X-ray pulsations lies in a limited range of values, $delta phi in$ (0 $-$ 0.15), which is maintained over timescales of about five years. This indicates that both pulsations originate from the same region, and it supports the hypothesis of a common emission mechanism. Our results are interpreted in the shock-driven mini pulsar nebula scenario. This scenario suggests that optical and X-ray pulses are produced by synchrotron emission from the shock that formed within a few light cylinder radii away ($sim$ 100 km) from the pulsar, where its striped wind encounters the accretion disk inflow. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12975v1
Taking a break: paused accretion in the symbiotic binary RT Cru by A. Pujol et al. on Thursday 24 November Symbiotic binaries sometimes hide their symbiotic nature for significant periods of time. There is mounting observational evidence that in those symbiotics that are powered solely by accretion of red-giant's wind material onto a white dwarf, without any quasi-steady shell burning on the surface of the white dwarf, the characteristic emission lines in the optical spectrum can vanish, leaving the semblance of an isolated red giant spectrum. Here we present compelling evidence that this disappearance of optical emission lines from the spectrum of RT Cru during 2019 was due to a decrease in the accretion rate, which we derive by modeling the X-ray spectrum. This drop in accretion rate leads to a lower flux of ionizing photons and thus to faint/absent photoionization emission lines in the optical spectrum. We observed the white dwarf symbiotic RT Cru with XMM-Newton and Swift in X-rays and UV and collected ground-based optical spectra and photometry over the last 33 years. This long-term coverage shows that during most of the year 2019, the accretion rate onto the white dwarf was so low, $dot{M}= (3.2pm 0.06), times$10$^{-11}$ $M_{odot}$ yr$^{-1}$ (d/2.52 kpc)$^2$, that the historically detected hard X-ray emission almost vanished, the UV flux faded by roughly 5 magnitudes, the $U$, $B$ and $V$ flickering amplitude decreased, and the Balmer lines virtually disappeared from January through March 2019. Long-lasting low-accretion episodes as the one reported here may hamper the chances of RT Cru experiencing nova-type outburst despite the high-mass of the accreting white dwarf. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.13193v1
Deep X-ray and radio observations of the first outburst of the young magnetar Swift J1818 0-1607 by A. Y. Ibrahim et al. on Thursday 24 November Swift J1818.0-1607 is a radio-loud magnetar with a spin period of 1.36 s and a dipolar magnetic field strength of B~3E14 G, which is very young compared to the Galactic pulsar population. We report here on the long-term X-ray monitoring campaign of this young magnetar using XMM-Newton, NuSTAR, and Swift from the activation of its first outburst in March 2020 until October 2021, as well as INTEGRAL upper limits on its hard X-ray emission. The 1-10 keV magnetar spectrum is well modeled by an absorbed blackbody with a temperature of kT_BB~1.1 keV, and apparent reduction in the radius of the emitting region from ~0.6 to ~0.2 km. We also confirm the bright diffuse X-ray emission around the source extending between ~50'' and ~110''. A timing analysis revealed large torque variability, with an average spin-down rate nudot~-2.3E-11 Hz^2 that appears to decrease in magnitude over time. We also observed Swift J1818.0-1607 with the Karl G. Jansky Very Large Array (VLA) on 2021 March 22. We detected the radio counterpart to Swift J1818.0-1607 measuring a flux density of S_v = 4.38+/-0.05 mJy at 3 GHz, and a half ring-like structure of bright diffuse radio emission located at ~90'' to the west of the magnetar. We tentatively suggest that the diffuse X-ray emission is due to a dust scattering halo and that the radio structure may be associated with the supernova remnant of this young pulsar, based on its morphology. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12391v1
On the cosmic evolution of AGN obscuration and the X-ray luminosity function: XMM-Newton and Chandra spectral analysis of the 31 3 deg ^2 Stripe 82X by Alessandro Peca et al. on Wednesday 23 November We present X-ray spectral analysis of XMM and Chandra observations in the 31.3 deg$^2$ Stripe-82X (S82X) field. Of the 6181 X-ray sources in this field, we analyze a sample of 2937 active galactic nuclei (AGN) with solid redshifts and sufficient counts determined by simulations. Our results show a population with median values of spectral index $Gamma=1.94_{-0.39}^{+0.31}$, column density log$,N_{mathrm{H}}/mathrm{cm}^{-2}=20.7_{-0.5}^{+1.2}$ and intrinsic, de-absorbed, 2-10 keV luminosity log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}=44.0_{-1.0}^{+0.7}$, in the redshift range 0-4. We derive the intrinsic fraction of AGN that are obscured ($22leqmathrm{log},N_{mathrm{H}}/mathrm{cm}^{-2}43$. This work constrains the AGN obscuration and spectral shape of the still uncertain high-luminosity and high-redshift regimes (log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}>45.5$, $z>3$), where the obscured AGN fraction rises to $64pm12%$. We report a luminosity and density evolution of the X-ray luminosity function, with obscured AGN dominating at all luminosities at $z>2$ and unobscured sources prevailing at log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}>45$ at lower redshifts. Our results agree with evolutionary models in which the bulk of AGN activity is triggered by gas-rich environments and in a downsizing scenario. Also, the black hole accretion density (BHAD) is found to evolve similarly to the star formation rate density, confirming the co-evolution between AGN and host-galaxy, but suggesting different time scales in their growing history. The derived BHAD evolution shows that Compton-thick AGN contribute to the accretion history of AGN as much as all other AGN populations combined. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.08030v2
Deep X-ray and radio observations of the first outburst of the young magnetar Swift J1818 0-1607 by A. Y. Ibrahim et al. on Wednesday 23 November Swift J1818.0-1607 is a radio-loud magnetar with a spin period of 1.36 s and a dipolar magnetic field strength of B~3E14 G, which is very young compared to the Galactic pulsar population. We report here on the long-term X-ray monitoring campaign of this young magnetar using XMM-Newton, NuSTAR, and Swift from the activation of its first outburst in March 2020 until October 2021, as well as INTEGRAL upper limits on its hard X-ray emission. The 1-10 keV magnetar spectrum is well modeled by an absorbed blackbody with a temperature of kT_BB~1.1 keV, and apparent reduction in the radius of the emitting region from ~0.6 to ~0.2 km. We also confirm the bright diffuse X-ray emission around the source extending between ~50'' and ~110''. A timing analysis revealed large torque variability, with an average spin-down rate nudot~-2.3E-11 Hz^2 that appears to decrease in magnitude over time. We also observed Swift J1818.0-1607 with the Karl G. Jansky Very Large Array (VLA) on 2021 March 22. We detected the radio counterpart to Swift J1818.0-1607 measuring a flux density of S_v = 4.38+/-0.05 mJy at 3 GHz, and a half ring-like structure of bright diffuse radio emission located at ~90'' to the west of the magnetar. We tentatively suggest that the diffuse X-ray emission is due to a dust scattering halo and that the radio structure may be associated with the supernova remnant of this young pulsar, based on its morphology. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12391v1
Deep X-ray and radio observations of the first outburst of the young magnetar Swift J1818 0-1607 by A. Y. Ibrahim et al. on Wednesday 23 November Swift J1818.0-1607 is a radio-loud magnetar with a spin period of 1.36 s and a dipolar magnetic field strength of B~3E14 G, which is very young compared to the Galactic pulsar population. We report here on the long-term X-ray monitoring campaign of this young magnetar using XMM-Newton, NuSTAR, and Swift from the activation of its first outburst in March 2020 until October 2021, as well as INTEGRAL upper limits on its hard X-ray emission. The 1-10 keV magnetar spectrum is well modeled by an absorbed blackbody with a temperature of kT_BB~1.1 keV, and apparent reduction in the radius of the emitting region from ~0.6 to ~0.2 km. We also confirm the bright diffuse X-ray emission around the source extending between ~50'' and ~110''. A timing analysis revealed large torque variability, with an average spin-down rate nudot~-2.3E-11 Hz^2 that appears to decrease in magnitude over time. We also observed Swift J1818.0-1607 with the Karl G. Jansky Very Large Array (VLA) on 2021 March 22. We detected the radio counterpart to Swift J1818.0-1607 measuring a flux density of S_v = 4.38+/-0.05 mJy at 3 GHz, and a half ring-like structure of bright diffuse radio emission located at ~90'' to the west of the magnetar. We tentatively suggest that the diffuse X-ray emission is due to a dust scattering halo and that the radio structure may be associated with the supernova remnant of this young pulsar, based on its morphology. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12391v1
On the cosmic evolution of AGN obscuration and the X-ray luminosity function: XMM-Newton and Chandra spectral analysis of the 31 3 deg ^2 Stripe 82X by Alessandro Peca et al. on Tuesday 22 November We present X-ray spectral analysis of XMM and Chandra observations in the 31.3 deg$^2$ Stripe-82X (S82X) field. Of the 6181 X-ray sources in this field, we analyze a sample of 2937 active galactic nuclei (AGN) with solid redshifts and sufficient counts determined by simulations. Our results show a population with median values of spectral index $Gamma=1.94_{-0.39}^{+0.31}$, column density log$,N_{mathrm{H}}/mathrm{cm}^{-2}=20.7_{-0.5}^{+1.2}$ and intrinsic, de-absorbed, 2-10 keV luminosity log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}=44.0_{-1.0}^{+0.7}$, in the redshift range 0-4. We derive the intrinsic fraction of AGN that are obscured ($22leqmathrm{log},N_{mathrm{H}}/mathrm{cm}^{-2}43$. This work constrains the AGN obscuration and spectral shape of the still uncertain high-luminosity and high-redshift regimes (log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}>45.5$, $z>3$), where the obscured AGN fraction rises to $64pm12%$. We report a luminosity and density evolution of the X-ray luminosity function, with obscured AGN dominating at all luminosities at $z>2$ and unobscured sources prevailing at log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}>45$ at lower redshifts. Our results agree with evolutionary models in which the bulk of AGN activity is triggered by gas-rich environments and in a downsizing scenario. Also, the black hole accretion density (BHAD) is found to evolve similarly to the star formation rate density, confirming the co-evolution between AGN and host-galaxy, but suggesting different time scales in their growing history. The derived BHAD evolution shows that Compton-thick AGN contribute to the accretion history of AGN as much as all other AGN populations combined. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.08030v2
On the cosmic evolution of AGN obscuration and the X-ray luminosity function: XMM-Newton and Chandra spectral analysis of the 31 3 deg ^2 Stripe 82X by Alessandro Peca et al. on Tuesday 22 November We present X-ray spectral analysis of XMM and Chandra observations in the 31.3 deg$^2$ Stripe-82X (S82X) field. Of the 6181 X-ray sources in this field, we analyze a sample of 2937 active galactic nuclei (AGN) with solid redshifts and sufficient counts determined by simulations. Our results show a population with median values of spectral index $Gamma=1.94_{-0.39}^{+0.31}$, column density log$,N_{mathrm{H}}/mathrm{cm}^{-2}=20.7_{-0.5}^{+1.2}$ and intrinsic, de-absorbed, 2-10 keV luminosity log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}=44.0_{-1.0}^{+0.7}$, in the redshift range 0-4. We derive the intrinsic fraction of AGN that are obscured ($22leqmathrm{log},N_{mathrm{H}}/mathrm{cm}^{-2}43$. This work constrains the AGN obscuration and spectral shape of the still uncertain high-luminosity and high-redshift regimes (log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}>45.5$, $z>3$), where the obscured AGN fraction rises to $64pm12%$. We report a luminosity and density evolution of the X-ray luminosity function, with obscured AGN dominating at all luminosities at $z>2$ and unobscured sources prevailing at log$,L_{mathrm{X}}/mathrm{erg,s}^{-1}>45$ at lower redshifts. Our results agree with evolutionary models in which the bulk of AGN activity is triggered by gas-rich environments and in a downsizing scenario. Also, the black hole accretion density (BHAD) is found to evolve similarly to the star formation rate density, confirming the co-evolution between AGN and host-galaxy, but suggesting different time scales in their growing history. The derived BHAD evolution shows that Compton-thick AGN contribute to the accretion history of AGN as much as all other AGN populations combined. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.08030v2
Timescale-dependent X-ray to UV time lags of NGC 4593 using high-intensity XMM-Newton observations with Swift and AstroSat by Max W. J. Beard et al. on Monday 21 November We present a 140ks observation of NGC 4593 with XMM-Newton providing simultaneous and continuous PN X-ray and OM UV (UVW1 2910AA) lightcurves which sample short-timescale variations better than previous observations. These observations were simultaneous with 22d of Swift X-ray and UV/optical monitoring, reported previously, and 4d of AstroSat X-ray (SXT), far (FUV 1541AA), and near (NUV 2632AA) UV allowing lag measurements between them and the highly-sampled XMM. From the XMM we find that UVW1 lags behind the X-rays by 29.5$pm$1.3ks, $sim$half the lag previously determined from the Swift monitoring. Re-examination of the textit{Swift} data reveals a bimodal lag distribution, with evidence for both the long and short lags. However if we detrend the Swift lightcurves by LOWESS filtering with a 5d width, only the shorter lag (23.8$pm$21.2ks) remains. The NUV observations, compared to PN and SXT, confirm the $sim$30ks lag found by XMM and, after 4d filtering is applied to remove the long-timescale component, the FUV shows a lag of $sim$23ks. The resultant new UVW1, FUV, and NUV lag spectrum extends to the X-ray band without requiring additional X-ray to UV lag offset, which if the UV arises from reprocessing of X-rays, implies direct illumination of the reprocessor. By referencing previous Swift and HST lag measurements, we obtain an X-ray to optical lag spectrum which agrees with a model using the KYNreverb disc-reprocessing code, assuming the accepted mass of $7.63times10^{6}M_{odot}$ and a spin approaching maximum. Previously noted lag contribution from the BLR in the Balmer and Paschen continua are still prominent. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.10229v1
Variability In A Low-Mass AGN: Oscillation Or Eruption? by Robbie Webbe et al. on Monday 21 November Following the discovery of a new class of X-ray variability seen in four galaxies, dubbed Quasi-Periodic Eruptions (QPEs), we reconsider the variability seen in the low-mass AGN 2XMM J123103.2+110648 to ascertain whether it should be considered the fifth QPE host galaxy. We apply the autocorrelation function to two archival XMM-Newton observations to determine characteristic timescales for variability of $sim$ 13.52 ks and $sim$ 14.35 ks. The modelling of lightcurves, both folded at these timescales and unfolded, indicates that a Gaussian model is preferable over a sinusoidal model, with average durations for the bright phases of 6.17 ks and 7.69 ks. In a broad 0.2-1.0 keV band the average amplitude of the bright phases was found to be 2.86 and 8.56 times the quiescent count rate. The pattern of variability seen in 2XMM J123103.2+110648 cannot be definitively declared as a series of Quasi-Periodic Eruptions. Instead, this suggests there may be a continuum of quasi-periodic variability ranging from eruptions to oscillations being caused by a single mechanism. This offers the possibility of finding further sources that continue to bridge the gap between QPEs and Quasi-Periodic Oscillations. A targeted analysis of 47 observations of 11 other low-mass AGN $(log(M_{BH}) lesssim 6)$ found no evidence of QPE or QPO-like behaviour in a sample of other similar mass objects. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.10176v1
L'analyse des données archivées du télescope spatial XMM-Newton a dévoilé une variabilité très inhabituelle dans l'émission en rayons X mous de PSR J1311-3430, un pulsar milliseconde veuve noire en couple serré avec une étoile compagne de très faible masse (M ∼ 0,01 M⊙). Une périodicité de 2h transitoire est observée alors que la période orbitale du couple est de 1,5 heure. Aucun modèle n'explique cette observation… L'étude est publiée dans Astronomy&Astrophysics.
Broadband X-ray Spectral Analysis of the Dual AGN System Mrk 739 by Koki Inaba et al. on Monday 17 October We present the result of a broadband (0.5-70 keV) X-ray spectral analysis of the late-merger galaxy Mrk 739, which contains a dual active galactic nucleus (AGN), Mrk 739E and Mrk 739W, with a separation of $sim$3.4 kpc. The spectra obtained with NuSTAR, Chandra, XMM-Newton and Swift/BAT are simultaneously analyzed by separating the contributions from the two AGNs and extended emission with the Chandra data. To evaluate the reflection components from the AGN tori, we consider two models, a phenomenological one (pexrav and zgauss) and a more physically motivated one (XCLUMPY; Tanimoto et al. 2019). On the basis of the results with XCLUMPY, we find that the AGNs in Mrk 739E and Mrk 739W have intrinsic 2-10 keV luminosities of $1.0 times 10^{43}$ and $7.5 times 10^{41} rm{erg} rm{s}^{-1}$ absorbed by hydrogen column densities of $N_{rm{H}} < 6.5 times 10^{19} rm{cm}^{-2}$ and $N_{rm{H}} = 6.9^{+3.2}_{-1.7} times 10^{21} rm{cm}^{-2}$, respectively. The torus covering fraction of the material with $N_{rm{H}} > 10^{22} rm{cm}^{-2}$ in Mrk 739E, $C_{rm{T}}^{(22)} < 0.50$ at a 90% confidence limit, is found to be smaller than those found for late-merger ultra/luminous infrared galaxies, $C_{rm{T}}^{(22)} = 0.71pm0.16$ (mean and standard deviation; Yamada et al. 2021). Considering the small star formation rate of Mrk 739E, we suggest that the gas-to-mass ratio of the host galaxy is an important parameter to determine the circumnuclear environment of an AGN in late merger. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.08791v1
On the cosmic evolution of AGN obscuration and the X-ray luminosity function: XMM-Newton and Chandra spectral analysis of the 31 3 deg ^2 Stripe 82X by Alessandro Peca et al. on Monday 17 October We present X-ray spectral analysis of XMM and Chandra observations in the 31.3 deg$^2$ Stripe-82X (S82X) field. Of the 6181 unique X-ray sources in this field, we select and analyze a sample of 2937 candidate active galactic nuclei (AGN) with solid redshifts and sufficient counts determined by simulations. Our results show an observed population with median values of spectral index $Gamma=1.94_{-0.39}^{+0.31}$, column density log $N_H/rm{cm}^{-2}=20.7_{-0.5}^{+1.2}$ ($21.6_{-0.9}^{+0.7}$ considering upper limits) and intrinsic, de-absorbed, 2-10 keV luminosity log $L_X/rm{erg,s}^{-1}=44.0_{-1.0}^{+0.7}$, in the redshift range 0-4. Correcting for observational biases, we derive the intrinsic, model-independent, fraction of AGN that are obscured ($22leqrm{log},N_H/rm{cm}^{-2}43$. This work constrains the AGN obscuration and spectral shape of the still uncertain high-luminosity and high-redshift regimes (log $L_X/rm{erg,s}^{-1}>45.5$, $z>3$), where the obscured AGN fraction rises to $64pm12%$. The total, obscured, and unobscured X-ray luminosity functions (XLFs) are determined out to $z=4$. We report a luminosity and density evolution of the total XLF, with obscured AGN dominating at all luminosities at $z>2$ and unobscured sources prevailing at log $L_X/rm{erg,s}^{-1}>45$ at lower redshifts. Our results agree with the evolutionary models in which the bulk of AGN activity is triggered by gas-rich environments and in a downsizing scenario. Also, the black hole accretion density is found to evolve similarly to the star formation rate density, confirming the co-evolution scenario between AGN and host galaxy, but suggesting different time scales in their growing history. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.08030v1
Swift and XMM-Newton observations of an RS CVn type eclipsing binary SZ Psc: Superflare and coronal properties by Subhajeet Karmakar et al. on Sunday 16 October We present an in-depth study of a large and long duration ($>$1.3 days) X-ray flare observed on an RS CVn type eclipsing binary system SZ Psc using observations from Swift observatory. In the 0.35$-$10 keV energy band, the peak luminosity is estimated to be 4.2$times$10$^{33}$ erg s$^{-1}$. The quiescent corona of SZ Psc was observed $sim$5.67 d after the flare using Swift observatory, and also $sim$1.4 yr after the flare using the XMM-Newton satellite. The quiescent corona is found to consist of three temperature plasma: 4, 13, and 48 MK. High-resolution X-ray spectral analysis of the quiescent corona of SZ Psc suggests that the high first ionization potential (FIP) elements are more abundant than the low-FIP elements. The time-resolved X-ray spectroscopy of the flare shows a significant variation in the flare temperature, emission measure, and abundance. The peak values of temperature, emission measure, and abundances during the flare are estimated to be 199$pm$11 MK, 2.13$pm$0.05 $times 10^{56}$ cm$^{-3}$, 0.66$pm$0.09 Z$_{odot}$, respectively. Using the hydrodynamic loop modeling, we derive the loop length of the flare as 6.3$pm$0.5 $times 10^{11}$ cm, whereas the loop pressure and density at the flare peak are derived to be 3.5$pm$0.7 $times 10^{3}$ dyne cm$^{-2}$ and 8$pm$2 $times 10^{10}$ cm$^{-3}$, respectively. The total magnetic field to produce the flare is estimated to be 490$pm$60 G. The large magnetic field at the coronal height is supposed to be due to the presence of an extended convection zone of the sub-giant and the high orbital velocity. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.07170v1
A Swift X-ray view of the SMS4 sample -- X-ray properties of 31 quasars and radio galaxies by Alessandro Maselli et al. on Sunday 16 October We present Swift observations of 31 sources from the SMS4 catalog, a sample of 137 bright radio sources in the Southern Hemisphere. All these sources had no Chandra or XMM-Newton observations: 24 of these were observed with Swift through a dedicated proposal in 2015, and data for the remaining seven were retrieved from the Swift archive. The reduction and analysis of data collected by the Swift X-ray Telescope (XRT) led to 20 detections in the 0.3--10 keV band. We provide details of the X-ray emission in this band for these 20 detections, as well as upper limits for the remaining 11 SMS4 sources. When statistics allowed, we investigated the extent of the X-ray emission, the hardness ratio, and we carried out a spectral analysis. We matched the 20 X-ray detected sources with infrared (AllWISE, CatWISE2020) and optical (GSC 2.3.2, DES DR2) catalogs to establish associations with infrared and optical sources, and compared our results with previously published counterparts in these bands. Requiring a detection in both the infrared and the optical bands to establish a candidate counterpart for our X-ray detections, we obtain reliable counterparts for 18 sources, while the remaining two sources need further investigation to establish firm identifications. We find that ~35% of all the SMS4 sources lie below the lower limit of 10.9 Jy for the flux density at 178 MHz. We present the list of 56 SMS4 sources that in 2022 March remain to be observed in the X-rays with narrow-field instruments. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2208.04763v2
Swift and XMM-Newton observations of an RS CVn type eclipsing binary SZ Psc: Superflare and coronal properties by Subhajeet Karmakar et al. on Sunday 16 October We present an in-depth study of a large and long duration ($>$1.3 days) X-ray flare observed on an RS CVn type eclipsing binary system SZ Psc using observations from Swift observatory. In the 0.35$-$10 keV energy band, the peak luminosity is estimated to be 4.2$times$10$^{33}$ erg s$^{-1}$. The quiescent corona of SZ Psc was observed $sim$5.67 d after the flare using Swift observatory, and also $sim$1.4 yr after the flare using the XMM-Newton satellite. The quiescent corona is found to consist of three temperature plasma: 4, 13, and 48 MK. High-resolution X-ray spectral analysis of the quiescent corona of SZ Psc suggests that the high first ionization potential (FIP) elements are more abundant than the low-FIP elements. The time-resolved X-ray spectroscopy of the flare shows a significant variation in the flare temperature, emission measure, and abundance. The peak values of temperature, emission measure, and abundances during the flare are estimated to be 199$pm$11 MK, 2.13$pm$0.05 $times 10^{56}$ cm$^{-3}$, 0.66$pm$0.09 Z$_{odot}$, respectively. Using the hydrodynamic loop modeling, we derive the loop length of the flare as 6.3$pm$0.5 $times 10^{11}$ cm, whereas the loop pressure and density at the flare peak are derived to be 3.5$pm$0.7 $times 10^{3}$ dyne cm$^{-2}$ and 8$pm$2 $times 10^{10}$ cm$^{-3}$, respectively. The total magnetic field to produce the flare is estimated to be 490$pm$60 G. The large magnetic field at the coronal height is supposed to be due to the presence of an extended convection zone of the sub-giant and the high orbital velocity. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.07170v1
The Planck clusters in the LOFAR sky III LoTSS-DR2: Dynamic states and density fluctuations of the intracluster medium by X. Zhang et al. on Sunday 16 October The footprint of LoTSS-DR2 covers 309 PSZ2 galaxy clusters, 83 of which host a radio halo and 26 host a radio relic(s). It provides us an excellent opportunity to statistically study the properties of extended cluster radio sources, especially their connection with merging activities. We aim to quantify cluster dynamic states to investigate their relation with the occurrence of extended radio sources. We also search for connections between intracluster medium (ICM) turbulence and nonthermal characteristics of radio halos in the LoTSS-DR2. We analyzed XMM-Newton and Chandra archival X-ray data and computed concentration parameters and centroid shifts that indicate the dynamic states of the clusters. We also performed a power spectral analysis of the X-ray surface brightness (SB) fluctuations to investigate large-scale density perturbations and estimate the turbulent velocity dispersion. The power spectral analysis results in a large scatter density fluctuation amplitude. We therefore only found a marginal anticorrelation between density fluctuations and cluster relaxation state, and we did not find a correlation between density fluctuations and radio halo power. Nevertheless, the injected power for particle acceleration calculated from turbulent dissipation is correlated with the radio halo power, where the best-fit unity slope supports the turbulent (re)acceleration scenario. Two different acceleration models, transit-time damping and adiabatic stochastic acceleration, cannot be distinguished due to the large scatter of the estimated turbulent Mach number. We introduced a new quantity $[kTcdot Y_X]_{r_mathrm{RH}}$, which is proportional to the turbulent acceleration power assuming a constant Mach number. This quantity is strongly correlated with radio halo power, where the slope is also unity. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.07284v1
Oxygen and iron in interstellar dust: an X-ray investigation by I. Psaradaki et al. on Wednesday 12 October Understanding the chemistry of the interstellar medium (ISM) is fundamental for the comprehension of the Galactic and stellar evolution. X-rays provide an excellent way to study the dust chemical composition and crystallinity along different sight-lines in the Galaxy. In this work we study the dust grain chemistry in the diffuse regions of the interstellar medium in the soft X-ray band (
The Jet Opening Angle and Event Rate Distributions of Short Gamma-ray Bursts from Late-time X-ray Afterglows by Alicia Rouco Escorial et al. on Wednesday 12 October We present a comprehensive study of 29 short gamma-ray bursts (SGRBs) observed $approx 0.8-60$ days post-burst using $Chandra$ and $XMM-Newton$. We provide the inferred distributions of SGRB jet opening angles and true event rates to compare against neutron star merger rates. We perform uniform analysis and modeling of their afterglows, obtaining 10 opening angle measurements and 19 lower limits. We report on two new opening angle measurements (SGRBs 050724A and 200411A) and eight updated values, obtaining a median value of $langle theta_{rm j} rangle approx 6.1^{circ}$ [-3.2$^{circ}$,+9.3$^{circ}$] (68% confidence on the full distribution) from jet measurements alone. For the remaining events, we infer $theta_{rm j}gtrsim 0.5-26^{circ}$. We uncover a population of SGRBs with wider jets of $theta_{rm j} gtrsim 10^{circ}$ (including two measurements of $theta_{rm j} gtrsim 15^{circ}$), representing $sim 28%$ of our sample. Coupled with multi-wavelength afterglow information, we derive a total true energy of $langle E_{rm true, tot} rangle approx 10^{49}-10^{50}$,erg which is consistent with MHD jet launching mechanisms. Furthermore, we determine a range for the beaming-corrected event rate of $mathfrak{R}_{rm true} approx360-1800$ Gpc$^{-3}$ yr$^{-1}$, set by the inclusion of a population of wide jets on the low end, and the jet measurements alone on the high end. From a comparison with the latest merger rates, our results are consistent with the majority of SGRBs originating from binary neutron star mergers. However, our inferred rates are well above the latest neutron star-black hole merger rates, consistent with at most a small fraction of SGRBs originating from such mergers. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.05695v1
Spectral Evolution of Ultraluminous X-ray Pulsar NGC 300 ULX-1 by Mason Ng et al. on Wednesday 12 October We report on results from a one-year soft X-ray observing campaign of the ultraluminous X-ray pulsar NGC 300 ULX-1 by the Neutron star Interior Composition Explorer (NICER) during 2018--2019. Our analysis also made use of data from Swift/XRT and XMM-Newton in order to model and remove contamination from the nearby eclipsing X-ray binary NGC 300 X-1. We constructed and fitted a series of 5-day averaged NICER spectra of NGC 300 ULX-1 in the 0.4--4.0 keV range to evaluate the long-term spectral evolution of the source, and found that an absorbed power-law model provided the best fit overall. Over the course of our observations, the source flux (0.4--4.0 keV; absorbed) dimmed from $2times10^{-12}$ to below $10^{-13}{rm,erg,s^{-1},cm^{-2}}$ and the spectrum softened, with the photon index going from $Gammaapprox1.6$ to $Gammaapprox2.6$. We interpret the spectral softening as reprocessed emission from the accretion disk edge coming into view while the pulsar was obscured by the possibly precessing disk. Some spectral fits were significantly improved by the inclusion of a disk blackbody component, and we surmise that this could be due to the pulsar emerging in between obscuration episodes by partial covering absorbers. We posit that we observed a low-flux state of the system (due to line-of-sight absorption) punctuated by the occasional appearance of the pulsar, indicating short-term source variability nested in longer-term accretion disk precession timescales. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.05678v1
Multi-wavelength study of the galactic PeVatron candidate LHAASO J2108+5157 by S. Abe et al. on Wednesday 12 October LHAASO J2108+5157 is one of the few known unidentified Ultra-High-Energy (UHE) gamma-ray sources with no Very-High-Energy (VHE) counterpart, recently discovered by the LHAASO collaboration. We observed LHAASO J2108+5157 in the X-ray band with XMM-Newton in 2021 for a total of 3.8 hours and at TeV energies with the Large-Sized Telescope prototype (LST-1), yielding 49 hours of good quality data. In addition, we analyzed 12 years of Fermi-LAT data, to better constrain emission of its High-Energy (HE) counterpart 4FGL J2108.0+5155. We found an excess (3.7 sigma) in the LST-1 data at energies E > 3 TeV. Further analysis in the whole LST-1 energy range assuming a point-like source, resulted in a hint (2.2 sigma) of hard emission which can be described with a single power law with photon index Gamma = 1.6 +- 0.2 between 0.3 - 100 TeV. We did not find any significant extended emission which could be related to a Supernova Remnant (SNR) or Pulsar Wind Nebula (PWN) in the XMM-Newton data, which puts strong constraints on possible synchrotron emission of relativistic electrons. The LST-1 and LHAASO observations can be explained as inverse Compton dominated leptonic emission of relativistic electrons with cutoff energy of 100+70-30 TeV. The low magnetic field in the source imposed by the X-ray upper limits on synchrotron emission is compatible with a hypothesis of a TeV halo. Furthermore, the spectral properties of the HE counterpart are consistent with a hypothesis of Geminga-like pulsar, which would be able to power the VHE-UHE emission. LST-1 and Fermi-LAT upper limits impose strong constraints on hadronic scenario of pi-0 decay dominated emission from accelerated protons interacting with nearby molecular clouds, requiring hard spectral index, which is incompatible with the standard diffusive acceleration scenario. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.00775v3
TRAPUM upper limits on pulsed radio emission for SMC X-ray pulsar J0058-7218 by E. Carli et al. on Tuesday 11 October The TRAPUM collaboration has used the MeerKAT telescope to conduct a search for pulsed radio emission from the young Small Magellanic Cloud pulsar J0058-7218 located in the supernova remnant IKT 16, following its discovery in X-rays with XMM-Newton. We report no significant detection of dispersed, pulsed radio emission from this source in three 2-hour L-band observations using the core dishes of MeerKAT, setting an upper limit of 7.0 {mu}Jy on its mean flux density at 1284 MHz. This is nearly 7 times deeper than previous radio searches for this pulsar in Parkes L-band observations. This suggests that the radio emission of PSR J0058-7218 is not beamed towards Earth or that PSR J0058-7218 is similar to a handful of Pulsar Wind Nebulae systems that have a very low radio efficiency, such as PSR B0540-6919, the Large Magellanic Cloud Crab pulsar analogue. We have also searched for bright, dispersed, single radio pulses and found no candidates above a fluence of 93 mJy ms at 1284 MHz. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.04785v1
TRAPUM upper limits on pulsed radio emission for SMC X-ray pulsar J0058-7218 by E. Carli et al. on Tuesday 11 October The TRAPUM collaboration has used the MeerKAT telescope to conduct a search for pulsed radio emission from the young Small Magellanic Cloud pulsar J0058-7218 located in the supernova remnant IKT 16, following its discovery in X-rays with XMM-Newton. We report no significant detection of dispersed, pulsed radio emission from this source in three 2-hour L-band observations using the core dishes of MeerKAT, setting an upper limit of 7.0 {mu}Jy on its mean flux density at 1284 MHz. This is nearly 7 times deeper than previous radio searches for this pulsar in Parkes L-band observations. This suggests that the radio emission of PSR J0058-7218 is not beamed towards Earth or that PSR J0058-7218 is similar to a handful of Pulsar Wind Nebulae systems that have a very low radio efficiency, such as PSR B0540-6919, the Large Magellanic Cloud Crab pulsar analogue. We have also searched for bright, dispersed, single radio pulses and found no candidates above a fluence of 93 mJy ms at 1284 MHz. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.04785v1
Multi-wavelength study of the galactic PeVatron candidate LHAASO J2108+5157 by S. Abe et al. on Tuesday 11 October LHAASO J2108+5157 is one of the few known unidentified Ultra-High-Energy (UHE) gamma-ray sources with no Very-High-Energy (VHE) counterpart, recently discovered by the LHAASO collaboration. We observed LHAASO J2108+5157 in the X-ray band with XMM-Newton in 2021 for a total of 3.8 hours and at TeV energies with the Large-Sized Telescope prototype (LST-1), yielding 49 hours of good quality data. In addition, we analyzed 12 years of Fermi-LAT data, to better constrain emission of its High-Energy (HE) counterpart 4FGL J2108.0+5155. We found an excess (3.7 sigma) in the LST-1 data at energies E > 3 TeV. Further analysis in the whole LST-1 energy range assuming a point-like source, resulted in a hint (2.2 sigma) of hard emission which can be described with a single power law with photon index Gamma = 1.6 +- 0.2 between 0.3 - 100 TeV. We did not find any significant extended emission which could be related to a Supernova Remnant (SNR) or Pulsar Wind Nebula (PWN) in the XMM-Newton data, which puts strong constraints on possible synchrotron emission of relativistic electrons. The LST-1 and LHAASO observations can be explained as inverse Compton dominated leptonic emission of relativistic electrons with cutoff energy of 100+70-30 TeV. The low magnetic field in the source imposed by the X-ray upper limits on synchrotron emission is compatible with a hypothesis of a TeV halo. Furthermore, the spectral properties of the HE counterpart are consistent with a hypothesis of Geminga-like pulsar, which would be able to power the VHE-UHE emission. LST-1 and Fermi-LAT upper limits impose strong constraints on hadronic scenario of pi-0 decay dominated emission from accelerated protons interacting with nearby molecular clouds, requiring hard spectral index, which is incompatible with the standard diffusive acceleration scenario. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.00775v2
A deep study of A399-401: An application for wide-field facet calibration by J. M. G. H. J. de Jong et al. on Monday 10 October We examine the particle acceleration mechanism in the Mpc-scale bridge between Abell 399 and Abell 401 and assess in particular if the synchrotron emission originates from first-order or second-order Fermi re-acceleration. We use deep (~40 hours) LOw-Frequency ARray (LOFAR) observations from Abell 399 and Abell 401 and apply improved direction-dependent calibration to produce deep radio images at three different resolutions at 144 MHz. With a point-to-point analysis we find in the bridge trends between the radio emission from our new maps and X-ray emission from an XMM Newton observation. By analyzing our observations and results, we argue that second-order Fermi re-acceleration is currently the most favoured process to explain the emission from the radio bridge, where past AGN activity may be responsible for the supply of fossil plasma needed for in-situ re-acceleration. The radio halos from Abell 401 and Abell 399 are also consistent with a second-order Fermi re-acceleration model. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.13930v3
SWIFT J0503 7-2819: A nearly synchronous intermediate polar below the period gap? by Nikita Rawat et al. on Sunday 25 September Based on the X-ray observations from XMM-Newton and Swift, and optical observations from Transiting Exoplanet Survey Satellite (TESS) and AAVSO, we present temporal and spectral properties of probable intermediate polar SWIFT J0503.7-2819. The X-ray light curve shows two distinctive features, where possibly the second pole seems to be active during the middle of the XMM-Newton observations. Present analysis confirms and also refines the previously reported orbital period of SWIFT J0503.7-2819 as 81.65$pm$0.04 min. The X-ray and optical variations of this target have been found to occur at the period of $sim$ 65 min, which we propose as the spin period of the white dwarf (WD). The energy-dependent modulation at this period, which are due to the photoelectric absorption in the accretion flow, also assures this conjecture. Two temperature thermal plasma model well explains the X-ray spectra with temperatures of $sim$ 150 eV and $sim$ 18.5 keV, which is absorbed by a dense material with an average equivalent hydrogen column density of 3.8 $times$ 10$^{22}$ cm$^{-2}$ that partially covers $sim$ 27% of the X-ray source. An attempt is made to understand the accretion flow in this system using the present data of SWIFT J0503.7-2819. If the proposed spin period is indeed the actual period, then SWIFT J0503.7-2819 could be the first nearly synchronous intermediate polar below the period gap. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.11141v1
SWIFT J0503 7-2819: A nearly synchronous intermediate polar below the period gap? by Nikita Rawat et al. on Sunday 25 September Based on the X-ray observations from XMM-Newton and Swift, and optical observations from Transiting Exoplanet Survey Satellite (TESS) and AAVSO, we present temporal and spectral properties of probable intermediate polar SWIFT J0503.7-2819. The X-ray light curve shows two distinctive features, where possibly the second pole seems to be active during the middle of the XMM-Newton observations. Present analysis confirms and also refines the previously reported orbital period of SWIFT J0503.7-2819 as 81.65$pm$0.04 min. The X-ray and optical variations of this target have been found to occur at the period of $sim$ 65 min, which we propose as the spin period of the white dwarf (WD). The energy-dependent modulation at this period, which are due to the photoelectric absorption in the accretion flow, also assures this conjecture. Two temperature thermal plasma model well explains the X-ray spectra with temperatures of $sim$ 150 eV and $sim$ 18.5 keV, which is absorbed by a dense material with an average equivalent hydrogen column density of 3.8 $times$ 10$^{22}$ cm$^{-2}$ that partially covers $sim$ 27% of the X-ray source. An attempt is made to understand the accretion flow in this system using the present data of SWIFT J0503.7-2819. If the proposed spin period is indeed the actual period, then SWIFT J0503.7-2819 could be the first nearly synchronous intermediate polar below the period gap. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.11141v1
X-ray spectral and timing analysis of the Compton Thick Seyfert 2 galaxy NGC 1068 by Indrani Pal et al. on Wednesday 21 September We present the timing and spectral analysis of the Compton Thick Seyfert 2 active galactic nuclei NGC 1068 observed using {it NuSTAR} and {it XMM-Newton}. In this work for the first time we calculated the coronal temperature ($rm{kT_{e}}$) of the source and checked for its variation between the epochs if any. The data analysed in this work comprised of (a) eight epochs of observations with {it NuSTAR} carried out during the period December 2012 to November 2017, and, (b) six epochs of observations with {it XMM-Newton} carried out during July 2000 to February 2015. From timing analysis of the {it NuSTAR} observations, we found the source not to show any variations in the soft band. However, on examination of the flux at energies beyond 20 keV, during August 2014 and August 2017 the source was brighter by about 20% and 30% respectively compared to the mean flux of the three 2012 {it NuSTAR} observations as in agreement with earlier results in literature. From an analysis of {it XMM-Newton} data we found no variation in the hard band (2 $-$ 4 keV) between epochs as well as within epochs. In the soft band (0.2 $-$ 2 keV), while the source was found to be not variable within epochs, it was found to be brighter in epoch B relative to epoch A. By fitting physical models we determined $rm{kT_{e}}$ to range between 8.46$^{+0.39}_{-0.66}$ keV and 9.13$^{+0.63}_{-0.98}$ keV. From our analysis, we conclude that we found no variation of $rm{kT_{e}}$ in the source. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.10261v1
CHEX-MATE: pressure profiles of 6 galaxy clusters as seen by SPT and Planck by Filippo Oppizzi et al. on Tuesday 20 September Pressure profiles are sensitive probes of the thermodynamic conditions and the internal structure of galaxy clusters. The intra-cluster gas resides in hydrostatic equilibrium within the Dark Matter gravitational potential. However, this equilibrium may be perturbed, e.g. as a consequence of thermal energy losses, feedback and non-thermal pressure supports. Accurate measures of the gas pressure over the cosmic times are crucial to constrain the cluster evolution as well as the contribution of astrophysical processes. In this work we presented a novel algorithm to derive the pressure profiles of galaxy clusters from the Sunyaev-Zeldovich (SZ) signal measured on a combination of Planck and South Pole Telescope (SPT) observations. The synergy of the two instruments made it possible to track the profiles on a wide range of spatial scales. We exploited the sensitivity to the larger scales of the Planck High-Frequency Instrument to observe the faint peripheries, and the higher spatial resolution of SPT to solve the innermost regions. We developed a two-step pipeline to take advantage of the specifications of each instrument. We first performed a component separation on the two data-sets separately to remove the background (CMB) and foreground (galactic emission) contaminants. Then we jointly fitted a parametric pressure profile model on a combination of Planck and SPT data. We validated our technique on a sample of 6 CHEX-MATE clusters detected by SPT. We compare the results of the SZ analysis with profiles derived from X-ray observations with XMM-Newton. We find an excellent agreement between these two independent probes of the gas pressure structure. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.09601v1
Constraining leptonic emission scenarios for the PeVatron candidate HESS J1702-420 with deep XMM-Newton observations by L. Giunti et al. on Tuesday 20 September The unidentified TeV source HESS J1702-420 has recently been proposed as a new hadronic PeVatron candidate, based on the discovery of a small-scale emission sub-region with extremely hard gamma-ray spectrum up to 100 TeV (named HESS J1702-420A). Given the difficulty to discriminate between a hadronic or leptonic origin of the TeV emission, based on the H.E.S.S. measurement alone, we opted for a multi-wavelength approach. A deep X-ray observation was carried out using the XMM-Newton satellite, with the goal of probing a possible association with a hidden leptonic accelerator. No evidence of a clear counterpart for HESS J1702-420A was found in the X-ray data. After excluding an association with all nearby X-ray point sources, we derived strict upper limits on the diffuse X-ray emission and average magnetic field in the HESS J1702-420A region. We additionally report the serendipitous discovery of a new extended X-ray source, whose association with HESS J1702-420A is not obvious but cannot be ruled out either. A set of scripts dedicated to the multi-wavelength modeling of X-ray and gamma-ray data, based on Gammapy, Naima and Xspec, was developed in the context of this work and is made publicly available along with this paper. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.09566v1
Correlated variability of the reflection fraction with the X-ray flux and spectral index for Mkn 478 by Samuzal Barua et al. on Monday 19 September The X-ray spectrum of Mkn 478 is known to be dominated by a strong soft excess which can be described using relativistic blurred reflection. Using observations from {it XMM-Newton}, {it AstroSat} and {it Swift}, we show that for the long-term ($sim$ years) and intermediate-term (days to months) variability, the reflection fraction is anti-correlated with the flux and spectral index, which implies that the variability is due to the hard X-ray producing corona moving closer to and further from the black hole. Using flux-resolved spectroscopy of the {it XMM-Newton} data, we show that the reflection fraction has the same behaviour with flux and index on short time-scales of hours. The results indicate that both the long-term and short-term variability of the source is determined by the same physical mechanism of strong gravitational light bending causing enhanced reflection and low flux as the corona moves closer to the black hole. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.08969v1
Multi-probe analysis of the galaxy cluster CL J1226 9+3332: Hydrostatic mass and hydrostatic-to-lensing bias by M. Muñoz-Echeverría et al. on Sunday 18 September The precise estimation of the mass of galaxy clusters is a major issue for cosmology. Large galaxy cluster surveys rely on scaling laws that relate cluster observables to their masses. From the high resolution observations of ~ 45 galaxy clusters with NIKA2 and XMM-Newton instruments, the NIKA2 SZ Large Program should provide an accurate scaling relation between the thermal Sunyaev-Zel'dovich effect and the hydrostatic mass. In this paper, we present an exhaustive analysis of the hydrostatic mass of the well known galaxy cluster CL J1226.9+3332, the highest-redshift cluster in the NIKA2 SZ Large Program at z = 0.89. We combine the NIKA2 observations with thermal Sunyaev-Zel'dovich data from NIKA, Bolocam and MUSTANG instruments and XMM-Newton X-ray observations and test the impact of the systematic effects on the mass reconstruction. We conclude that slight differences in the shape of the mass profile can be crucial when defining the integrated mass at R500, which demonstrates the importance of the modeling in the mass determination. We prove the robustness of our hydrostatic mass estimates by showing the agreement with all the results found in the literature. Another key information for cosmology is the bias of the masses estimated assuming hydrostatic equilibrium hypothesis. Based on the lensing convergence maps from the Cluster Lensing And Supernova survey with Hubble (CLASH) data, we obtain the lensing mass estimate for CL J1226.9+3332. From this we are able to measure the hydrostatic-to-lensing mass bias for this cluster, that spans from 1 - bHSE/lens ~ 0.7 to 1, presenting the impact of data-sets and mass reconstruction models on the bias. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.07460v1
Multi-probe analysis of the galaxy cluster CL J1226 9+3332: Hydrostatic mass and hydrostatic-to-lensing bias by M. Muñoz-Echeverría et al. on Sunday 18 September The precise estimation of the mass of galaxy clusters is a major issue for cosmology. Large galaxy cluster surveys rely on scaling laws that relate cluster observables to their masses. From the high resolution observations of ~ 45 galaxy clusters with NIKA2 and XMM-Newton instruments, the NIKA2 SZ Large Program should provide an accurate scaling relation between the thermal Sunyaev-Zel'dovich effect and the hydrostatic mass. In this paper, we present an exhaustive analysis of the hydrostatic mass of the well known galaxy cluster CL J1226.9+3332, the highest-redshift cluster in the NIKA2 SZ Large Program at z = 0.89. We combine the NIKA2 observations with thermal Sunyaev-Zel'dovich data from NIKA, Bolocam and MUSTANG instruments and XMM-Newton X-ray observations and test the impact of the systematic effects on the mass reconstruction. We conclude that slight differences in the shape of the mass profile can be crucial when defining the integrated mass at R500, which demonstrates the importance of the modeling in the mass determination. We prove the robustness of our hydrostatic mass estimates by showing the agreement with all the results found in the literature. Another key information for cosmology is the bias of the masses estimated assuming hydrostatic equilibrium hypothesis. Based on the lensing convergence maps from the Cluster Lensing And Supernova survey with Hubble (CLASH) data, we obtain the lensing mass estimate for CL J1226.9+3332. From this we are able to measure the hydrostatic-to-lensing mass bias for this cluster, that spans from 1 - bHSE/lens ~ 0.7 to 1, presenting the impact of data-sets and mass reconstruction models on the bias. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.07460v1
X-ray Intraday Variability of HBL Blazars with XMM-Newton by P. U. Devanand et al. on Tuesday 13 September We present an extensive study on the X-ray intraday variability of ten TeV-emitting high synchrotron peaked blazars (HBLs): 1ES 0229+200, 1ES 0414+009, PKS 0548-322, 1ES 1101-232, 1H 1219+301, H 1426+428, Mrk 501, 1ES 1959+650, PKS 2005-489, and 1ES 2344+514 made with twenty-five XMM-Newton pointed observations during its operational period. Intraday variability has been estimated in three energy bands: soft (0.3--2 keV), hard (2--10 keV) and total (0.3--10 keV). Although seven out of these ten TeV HBLs exhibited some intraday variability at three-sigma levels no major variations exceeding six percent were detected. We explored the spectral properties of the sample by extracting the hardness ratio from the soft and hard bands; no significant variations in the hardness ratio were observed in any source. We performed power spectral density analyses on the variable light-curves by fitting power-laws, yielding slopes lying in the range from 1.11 to 2.93 for different HBLs. We briefly discuss possible emission mechanisms and carry out rough estimates for magnetic fields, electron Lorentz factors and emission region sizes for seven of these HBLs. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.05515v1
Interstellar absorption and dust scattering by Elisa Costantini et al. on Tuesday 13 September The study of the interstellar medium (ISM) in the X-rays has entered a golden age with the advent of the X-ray observatories XMM-Newton and Chandra. High-energy resolution allowed to study dust spectroscopic features with unprecedented detail. At the same time, the X-ray imaging capabilities offered a new perspective of dust scattering halos. Both spectroscopy and imaging rely on a simple geometry, where a distant X-ray source, usually a bright X-ray binary system, lies behind a multi-layered ISM. X-ray binaries can be found in different regions in the Galaxy, providing the unique chance to study the ISM in distinct environments. In the following we will describe how X-rays can be used as a tool to study gas and dust along the line of sight, revealing elemental abundances and depletion. The study of interstellar dust spectroscopic and imaging features can be used to extract the chemical and physical properties of the intervening dust, as well as its distribution along the line of sight. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.05261v1
The Great Flare of 2021 November 19 on AD Leo Simultaneous XMM-Newton and TESS observations by B. Stelzer et al. on Monday 12 September We present a detailed analysis of a superflare on the active M dwarf star AD Leonis. The event presents a rare case of a stellar flare observed simultaneously in X-rays (with XMM-Newton) and in optical (with the Transiting Exoplanet Survey Satellite, TESS). The radiated energy both in the 0.2-12 keV X-ray band ($1.26 pm 0.01 cdot 10^{33}$ erg) and the bolometric value ($E_{F,bol} = 5.57 pm 0.03 cdot 10^{33}$ erg) put this event at the lower end of the superflare class. The exceptional photon statistics deriving from the proximity of AD Leo has enabled measurements in the 1-8 AA GOES band for the peak flux (X1445 class) and integrated energy ($E_{F,GOES} = 4.30 pm 0.05 cdot 10^{32}$ erg), making possible a direct comparison with data on flares from our Sun. From extrapolations of empirical relations for solar flares we estimate that a proton flux of at least $10^5,{cm^{-2} s^{-1} sr^{-1}}$ accompanied the radiative output. With a time lag of 300s between the peak of the TESS white-light flare and the GOES band flare peak as well as a clear Neupert effect this event follows very closely the standard (solar) flare scenario. Time-resolved spectroscopy during the X-ray flare reveals, in addition to the time evolution of plasma temperature and emission measure, a temporary increase of electron density and elemental abundances, and a loop that extends in the corona by 13% of the stellar radius ($4 cdot 10^9$ cm). Independent estimates of the footprint area of the flare from TESS and XMM-Newton data suggest a high temperature of the optical flare (25000 K), but we consider more likely that the optical and X-ray flare areas represent physically distinct regions in the atmosphere of AD Leo. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.05068v1
Two decades of X-ray observations of the isolated neutron star RX J1856 5-3754: detection of thermal and non-thermal hard X-rays and refined spin-down measurement by Davide De Grandis et al. on Sunday 11 September The soft X-ray pulsar RX J1856.5-3754 is the brightest member of a small class of thermally-emitting, radio-silent, isolated neutron stars. Its X-ray spectrum is almost indistinguishable from a blackbody with $kT^inftyapprox 60$ eV, but evidence of harder emission above $sim 1$ keV has been recently found. We report on a spectral and timing analysis of RX J1856.5-3754 based on the large amount of data collected by XMM-Newton in 2002--2022, complemented by a dense monitoring campaign carried out by NICER in 2019. Through a phase-coherent timing analysis we obtained an improved value of the spin-down rate $dot{nu}=-6.042(4)times10^{-16}$ Hz s$^{-1}$, reducing by more than one order magnitude the uncertainty of the previous measurement, and yielding a characteristic spin-down field of $1.47times10^{13}$ G. We also detect two spectral components above $sim1$ keV: a blackbody-like one with $kT^infty=138pm13$ eV and emitting radius $31_{-16}^{+8}$ m, and a power law with photon index $Gamma=1.4_{-0.4}^{+0.5}$. The power-law 2--8,keV flux, $(2.5_{-0.6}^{+0.7})times10{-15}$ erg cm$^{-2}$ s$^{-1}$, corresponds to an efficiency of $10^{-3}$, in line with that seen in other pulsars. We also reveal a small difference between the $0.1$--$0.3$ keV and $0.3$--$1.2$ keV pulse profiles, as well as some evidence for a modulation above $1.2$ keV. These results show that, notwithstanding its simple spectrum, eighteen still has a non-trivial thermal surface distribution and features non-thermal emission as seen in other pulsars with higher spin-down power. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.03874v1
Two decades of X-ray observations of the isolated neutron star RX J1856 5-3754: detection of thermal and non-thermal hard X-rays and refined spin-down measurement by Davide De Grandis et al. on Sunday 11 September The soft X-ray pulsar RX J1856.5-3754 is the brightest member of a small class of thermally-emitting, radio-silent, isolated neutron stars. Its X-ray spectrum is almost indistinguishable from a blackbody with $kT^inftyapprox 60$ eV, but evidence of harder emission above $sim 1$ keV has been recently found. We report on a spectral and timing analysis of RX J1856.5-3754 based on the large amount of data collected by XMM-Newton in 2002--2022, complemented by a dense monitoring campaign carried out by NICER in 2019. Through a phase-coherent timing analysis we obtained an improved value of the spin-down rate $dot{nu}=-6.042(4)times10^{-16}$ Hz s$^{-1}$, reducing by more than one order magnitude the uncertainty of the previous measurement, and yielding a characteristic spin-down field of $1.47times10^{13}$ G. We also detect two spectral components above $sim1$ keV: a blackbody-like one with $kT^infty=138pm13$ eV and emitting radius $31_{-16}^{+8}$ m, and a power law with photon index $Gamma=1.4_{-0.4}^{+0.5}$. The power-law 2--8,keV flux, $(2.5_{-0.6}^{+0.7})times10{-15}$ erg cm$^{-2}$ s$^{-1}$, corresponds to an efficiency of $10^{-3}$, in line with that seen in other pulsars. We also reveal a small difference between the $0.1$--$0.3$ keV and $0.3$--$1.2$ keV pulse profiles, as well as some evidence for a modulation above $1.2$ keV. These results show that, notwithstanding its simple spectrum, eighteen still has a non-trivial thermal surface distribution and features non-thermal emission as seen in other pulsars with higher spin-down power. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.03874v1
X-ray Absorption and Reprocessing in the z sim 2 5 Lensed Quasar 2MASS J1042+1641 by D. J. Walton et al. on Thursday 08 September We present new broadband X-ray observations of the $z sim 2.5$ lensed quasar 2MASS J1042+1641, combining $XMM$-$Newton$, $Chandra$ and $NuSTAR$ to provide coverage of the X-ray spectrum over the 0.3$-$40 keV bandpass in the observed frame, corresponding to the $sim$1$-$140 keV band in the rest-frame of 2MASS J1042+1641. The X-ray data show clear evidence for strong (but still Compton-thin) X-ray absorption, $N_{rm{H}} sim 3-4 times 10^{23}$ cm$^{-2}$, in addition to significant reprocessing by Compton-thick material that must lie away from our line-of-sight to the central X-ray source. We test two different interpretations for the latter: first that the reprocessing occurs in a classic AGN torus, as invoked in unification models, and second that the reprocessing occurs in the accretion disc. Both models can successfully reproduce the observed spectra, and both imply that the source is viewed at moderately low inclinations ($i < 50^{circ}$) despite the heavy line-of-sight absorption. Combining the X-ray data with infrared data from $WISE$, the results seen from 2MASS J1042+1641 further support the recent suggestion that large X-ray and IR surveys may together be able to identify good lensed quasar candidates in advance of detailed imaging studies. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.03381v1
The multi-epoch X-ray tale of I Zwicky 1 outflows by Daniele Rogantini et al. on Wednesday 07 September The narrow-line Seyfert 1 galaxy I Zwicky 1 shows a unique and complex system of ionised gas in outflow, which consists of an ultra-fast wind and a two-component warm absorber. In the last two decades, XMM-Newton monitored the source multiple times enabling the study of the long-term variability of the various outflows. Plasma in photoionisation equilibrium with the ionising source responds and varies accordingly to any change of the ionising luminosity. However, detailed modelling of the past RGS data has shown no correlation between the plasma ionisation state and the ionising continuum, revealing a complex long-term variability of the multi-phase warm absorber. Here, we present a new observation of I Zwicky 1 by XMM-Newton taken in early 2020 characterised by a lower X-ray flux state. The soft X-ray spectrum from the RGS reveals the two components of the warm absorber with $log xi sim -1.0$ and $log xi sim 1.7$. Comparing our results with the previous observations, the ionisation state of the two absorbing gas components is continuously changing, following the same unpredictable behaviour. The new results strengthen the scenario in which the ionisation state of the warm absorber is driven by the density of the gas rather than the ionising luminosity. In particular, the presence of a radiation driven, inhomogeneous clumpy outflow may explain both the variability in ionisation throughout the years and the line-locked N V system observed in the UV band. Finally, the EPIC-pn spectrum reveals an ultra-fast wind with an outflow velocity of $sim 0.26c$ and ionisation parameter of $log xi sim 3.8$. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.02747v1
Spectral variability in NGC 1042 ULX1 by Tanuman Ghosh et al. on Tuesday 06 September We report X-ray spectral variability in an ultraluminous X-ray source NGC 1042 ULX1, using archival XMM-NEWTON and recent NuSTAR observations. In long-term evolution, the source has shown a trend of variation in spectral hardness. The variability in different XMM-NEWTON observations is prominent above $sim 1$ keV. Cool thermal disk component with a characteristic temperature of $sim 0.2$ keV manifests that the spectral state of NGC 1042 ULX1 in all epochs is similar to that of the ultraluminous state sources. An apparent anti-correlation between luminosity and powerlaw index demonstrates that the source becomes spectrally harder when it is in a brighter state. That is conceivably related to stronger Comptonization when the accretion rate is higher or due to a change in the occultation of the disk geometry. Typical hard ultraluminous type spectra indicate that NGC 1042 ULX1 is a low inclination system in general. Spectral properties suggest that, like many other ULXs which show spectral curvature around $sim 6-10$ keV, NGC 1042 ULX1 could be another stellar-mass super-Eddington accretor. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.02458v1
Shocks in the outflow of the RS Oph 2021 eruption observed with X-ray gratings by Marina Orio et al. on Tuesday 06 September The 2021 outburst of the symbiotic recurrent nova RS Oph was observed with the Chandra High Energy Transmission Gratings (HETG) on day 18 after optical maximum and with XMM-Newton and its Reflection Grating Spectrographs (RGS) on day 21, before the supersoft X-ray source emerged and when the emission was due to shocked ejecta. The absorbed flux in the HETG 1.3-31 Angstrom range was 2.6 x 10(-10) erg/cm(-2)/s, three orders of magnitude lower than the gamma-ray flux measured on the same date. The spectra are well fitted with two components of thermal plasma in collisional ionization equilibrium, one at a temperature ~0.75 keV, and the other at temperature in the 2.5-3.4 keV range. With the RGS we measured an average flux 1.53 x 10(-10) erg/cm(-2)/s in the 5-35 Angstrom range, but the flux in the continuum and especially in the lines in the 23-35 Angstrom range decreased during the 50 ks RGS exposure by almost 10%, indicating short term variability on hours' time scale. The RGS spectrum can be fitted with three thermal components, respectively at plasma temperature between 70 and 150 eV, 0.64 keV and 2.4 keV. The post-maximum epochs of the exposures fall between those of two grating spectra observed in the 2006 eruption on days 14 and 26: they are consistent with a similar spectral evolution, but in 2021 cooling seems to have been more rapid. Iron is depleted in the ejecta with respect to solar values, while nitrogen is enhanced. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.02123v1
Magnetars... resten van overleden sterren, waar we het in het verleden al wel eens over hebben gehad (https://www.nporadio2.nl/podcasts/zimmerman-in-space/5718/44-magnetars-miljoenen-keren-sterker-dan-de-sterkste-magneten-op-aarde). Maar wat weten we eigenlijk over het binnenste van magnetars? Een recente ontdekking laat mogelijk wat meer licht over deze kwestie schijnen. De eerdere aflevering over magnetars: https://www.nporadio2.nl/podcasts/zimmerman-in-space/5718/44-magnetars-miljoenen-keren-sterker-dan-de-sterkste-magneten-op-aarde NICER telescoop: https://heasarc.gsfc.nasa.gov/docs/nicer/ XMM-Newton telescoop van ESA: https://xmm-tools.cosmos.esa.int/external/xmm_news/20th_Anniversary/ Sterrenbeeld Schild: https://nl.wikipedia.org/wiki/Schild_(sterrenbeeld) Wat is - denken we - de dwarsdoorsnede van een neutronenster: https://skyandtelescope.org/astronomy-news/whats-inside-neutron-stars/ Het gierenmuseum: https://www.maisondesvautours.fr/
The 365 Days of Astronomy, the daily podcast of the International Year of Astronomy 2009
https://www.youtube.com/watch?v=8Y266jhhteQ From February 5, 2019. Astronomers working with the NASA's Chandra X-Ray Observatory and ESA's XMM-Newton have developed a technique to watch quasars and track the expansion of the Universe over the last 9 billion years. What they found is that the mysterious dark energy that's currently accelerating the expansion of the Universe doesn't appear to be a fixed amount. It's changing, and appears to be increasing over time. If true, it's a groundbreaking discovery in cosmology, and it could just fortell the end of the Universe. We've added a new way to donate to 365 Days of Astronomy to support editing, hosting, and production costs. Just visit: https://www.patreon.com/365DaysOfAstronomy and donate as much as you can! Share the podcast with your friends and send the Patreon link to them too! Every bit helps! Thank you! ------------------------------------ Do go visit http://www.redbubble.com/people/CosmoQuestX/shop for cool Astronomy Cast and CosmoQuest t-shirts, coffee mugs and other awesomeness! http://cosmoquest.org/Donate This show is made possible through your donations. Thank you! (Haven't donated? It's not too late! Just click!) ------------------------------------ The 365 Days of Astronomy Podcast is produced by the Planetary Science Institute. http://www.psi.edu Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org.
Neurologist Suzanne O'Sullivan demystifies psychosomatic illnesses. Then, learn how scientists saw behind a black hole. Additional resources from neurologist Suzanne O'Sullivan Pick up "The Sleeping Beauties And Other Stories of Mystery Illness" here: https://www.penguinrandomhouse.com/books/606597/the-sleeping-beauties-by-suzanne-osullivan/ NHS page: https://www.uclh.nhs.uk/our-services/find-consultant/dr-suzanne-osullivan Follow @Suz_OSullivan on Twitter: https://twitter.com/Suz_OSullivan Scientists saw behind a black hole for the first time by Briana Brownell Wilkins, D. R., Gallo, L. C., Costantini, E., Brandt, W. N., & Blandford, R. D. (2021). Light bending and X-ray echoes from behind a supermassive black hole. Nature, 595(7869), 657–660. https://doi.org/10.1038/s41586-021-03667-0 XMM-Newton sees light echo from behind a black hole. (2021). Esa.int. https://www.esa.int/ESA_Multimedia/Images/2021/07/XMM-Newton_sees_light_echo_from_behind_a_black_hole Sophie, S. (2021, August 3). Astronomers spot light from behind a black hole for the first time — proving Einstein right, again. Cbsnews.com. https://www.cbsnews.com/news/supermassive-black-hole-light-behind-einstein/ Patel, N. V. (2021, July 28). Astronomers have spotted x-rays from behind a supermassive black hole. MIT Technology Review; MIT Technology Review. https://www.technologyreview.com/2021/07/28/1030233/x-rays-behind-supermassive-black-hole/ Shah, S. (2021). Scientists spot light behind a black hole for the first time | Engadget. Engadget; Engadget. https://www.engadget.com/black-hole-light-behind-092317917.html Follow Curiosity Daily on your favorite podcast app to learn something new every day withCody Gough andAshley Hamer. Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers. See omnystudio.com/listener for privacy information.
The 365 Days of Astronomy, the daily podcast of the International Year of Astronomy 2009
Once again, science has proved Einstein's theories correct. This time, observations taken with ESA's XMM-Newton and NASA's NuSTAR space telescopes have seen x-ray flashes bent from behind a black hole. Plus, so many exoplanet stories (Beth was left in charge) and this week's What's Up. We've added a new way to donate to 365 Days of Astronomy to support editing, hosting, and production costs. Just visit: https://www.patreon.com/365DaysOfAstronomy and donate as much as you can! Share the podcast with your friends and send the Patreon link to them too! Every bit helps! Thank you! ------------------------------------ Do go visit http://astrogear.spreadshirt.com/ for cool Astronomy Cast and CosmoQuest t-shirts, coffee mugs and other awesomeness! http://cosmoquest.org/Donate This show is made possible through your donations. Thank you! (Haven't donated? It's not too late! Just click!) The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. http://www.astrosphere.org/ Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org.
Once again, science has proved Einstein's theories correct. This time, observations taken with ESA's XMM-Newton and NASA's NuSTAR space telescopes have seen x-ray flashes bent from behind a black hole. Plus, so many exoplanet stories (Beth was left in charge) and this week's What's Up.
Depuis 40 ans, des aurores polaires émettrices de rayons X sont observées sur Jupiter sans être pleinement comprises. Mais aujourd'hui, grâce à des observations conjointes effectuées avec le télescope spatial européen XMM-Newton et la sonde américaine Juno, leur origine vient d'être déterminée. Une étude parue dans Science Advances sous le titre Revealing the source of Jupiter's x-ray auroral flares.
SpaceTime with Stuart Gary | Astronomy, Space & Science News
The Astronomy, Technology and Space Science News Podcast.SpaceTime Series 24 Episode 56*Blue Origin to start sending tourists to space in JulyBlue Origin will send its first people including at least one tourist to space on July 20.*XMM-Newton helping to unravel the mystery of ultra-luminous X-ray sources.A new study using the European Space Agency’s XMM-Newton space telescope may be on track to solving the mystery of so called ultra-luminous X-ray sources.*A new deep space dish for the New Norcia ground stationThe Australian Space Agency and its European counterpart have signed a deal to build a new 35-metre deep space antenna at the European Space Agency’s New Norcia ground station.*China another spy satelliteChina has launched another military spy satellite as it continues its build up for what Beijing describes as preparations for war.*The Science ReportLoneliness associated with an increased risk of cancerAir pollution found to impact the cognitive performance of men.A quantum entanglement study has disproved the Heisenberg uncertainty principle.Long-term spaceflight causing changes in the structure of astronaut’s eyes.Alex on Tech: Intel launches its new 11th-generation Core H series processor.Your support is needed...SpaceTime is an independently produced podcast (we are not funded by any government grants, big organisations or companies), and we’re working towards becoming a completely listener supported show...meaning we can do away with the commercials and sponsors. We figure the time can be much better spent on researching and producing stories for you, rather than having to chase sponsors to help us pay the bills.That's where you come in....help us reach our first 1,000 subscribers...at that level the show becomes financially viable and bills can be paid without us breaking into a sweat every month. Every little bit helps...even if you could contribute just $1 per month. It all adds up.By signing up and becoming a supporter at the $5 or more level, you get immediate access to over 230 commercial-free, double, and triple episode editions of SpaceTime plus extended interview bonus content. You also receive all new episodes on a Monday rather than having to wait the week out. Subscribe via Patreon or Supercast....and share in the rewards. Details at Patreon www.patreon.com/spacetimewithstuartgary or Supercast - https://bitesznetwork.supercast.tech/Details at https://spacetimewithstuartgary.com or www.bitesz.com Sponsor Details:This episode of SpaceTime is brought to you with the support of NordVPN…The world’s leading VPN provider. Making your online data unreadable to others.Check them out and get our big discount offer, plus help support SpaceTime… visit https://nordvpn.com/stuartgary or use the coupon code STUARTGARY at checkout. Thank you… For more SpaceTime visit https://spacetimewithstuartgary.com (mobile friendly).For enhanced Show Notes including photos to accompany this episode:
This highly detailed image of the Crab Nebula combines data from telescopes spanning nearly the entire breadth of the electromagnetic spectrum. The picture includes data from five different telescopes: the Spitzer Space Telescope (infrared) in yellow; the Karl G. Jansky Very Large Array (radio) in red; Hubble Space Telescope (visible) in green; XMM-Newton (ultraviolet) in blue; and Chandra X-ray Observatory (X-ray) in purple. Notice that the green color is all we can (could) see with our own eyes. The rest is invisible to natural human sight. Friends of the Show get all Premium Content! Thank you to my newest Friends of the Show: George S; Valerie K; Erin K; Stacy C; and Dori S, for loving and lifting me! LOVE the Word® is a Bible study method based on Mary's own practice: lectio without the Latin. Get the book based on Sonja's method in the right margin, How to Pray Like Mary. L - Listen (Receive the Word via audio or video.) O - Observe (Connect the passage to your life and recent events.) Read this article to learn how college students are living out the call to solidarity as CRS Student Ambassadors. How can you work to educate others about issues that impact our brothers and sisters at home and around the world? or Explore quantum mechanics here. From the Examination of Conscience in Light of Social Teaching Do you believe that “we are all really responsible for all”? If so, how does this challenge you? How can you join with others to take concrete steps—big or small—to help build a society of solidarity? Does the way I spend my time reflect a genuine concern for others? Is solidarity incorporated into my prayer and spirituality? Do I lift up vulnerable people throughout the world in my prayer, or is it reserved for only my personal concerns? Am I attentive only to my local neighbors or also those across the globe? Do I see all members of the human family as my brothers and sisters? V - Verbalize (Pray about your thoughts and emotions.) Remembering that He loves you and that you are in His presence, talk to God about the particulars of your O – Observe step. You may want to write your reflections in your LOVE the Word® journal. Or, get a free journal page and guide in the right-hand margin. E - Entrust (May it be done to me according to your word!) Lord, Creator, and Father of all people, sensitize me to the suffering of others so that I can overcome indifference and build up a civilization of love and solidarity. Amen + Show Notes Topics Discussed: Catholic social justice principle #6, solidarity and connectedness Quantum mechanics and God Pope Benedict XVI, Charity in Truth (Caritas in Veritate) St. Catherine of Sienna's Dialogue St. Thomas Aqunias' Summa on being (existence), evil, and angels Overview: Minutes 00:12:00 - Solidarity as oneness, the science behind oneness Minutes 12:01-24:00 - Quantum mechanics and God Minutes 24:01-36:00 - Love as the connecting energy, Matthew 18:21-34 and the parable of the unforgiving servant Minutes 36:01-48:00 - Gratitude and forgiveness as ways to act in solidarity with all Additional Resources: More on Solidarity from the Bible and Church documents United States Conference of Catholic Bishops, Seven Themes of Catholic Social Teaching Book, Amazon: Compendium of the Social Doctrine of the Church, Pontifical Council for Justice and Peace and USCCB Bible Study Evangelista is on the Laudate app! Facebook Discussion Community We're talking about solidarity over on the Bible Study Evangelista Facebook Discussion page. Come chat with us. Read the Transcript You can download a complete, word-for-word transcript of this show, here.
La galaxie du Feu d'Artifice (alias NGC 6946) a encore frappé ! Cette galaxie célèbre pour sa richesse en supernovas était observée avec le télescope spatial NuSTAR associé à XMM-Newton pour étudier ses sources X ultra-lumineuses, lorsqu'une nouvelle source X inconnue est apparue non loin du centre de la galaxie, puis a disparu aussi vite qu'elle était apparue. Elle pourrait avoir plusieurs origines... Une étude parue dans The Astrophysical Journal.
Astronomers working with the NASA's Chandra X-Ray Observatory and ESA's XMM-Newton have developed a technique to watch quasars and track the expansion of the Universe over the last 9 billion years. What they found is that the mysterious dark energy that's currently accelerating the expansion of the Universe doesn't appear to be a fixed amount. It's changing, and appears to be increasing over time. If true, it's a groundbreaking discovery in cosmology, and it could just fortel the end of the Universe.Support Universe Today Podcast
Astronomers working with the NASA’s Chandra X-Ray Observatory and ESA’s XMM-Newton have developed a technique to watch quasars and track the expansion of the Universe over the last 9 billion years. What they found is that the mysterious dark energy that’s currently accelerating the expansion of the Universe doesn’t appear to be a fixed amount. It’s changing, and appears to be increasing over time. If true, it’s a groundbreaking discovery in cosmology, and it could just fortel the end of the Universe.
Des astrophysiciens viennent de découvrir, grâce aux données des télescopes spatiaux XMM-Newton et Chandra, 3 pulsars qui produisent une émission de rayons X pulsée, et qui colle parfaitement avec les prédictions théoriques. Cette émission est également liée à l'émission de rayons gamma.
365 amas de galaxies, plus de 26000 noyaux actifs de galaxies, c'est le résultat de la moisson foisonnante de la deuxième livraison du grand relevé XXL du télescope spatial européen XMM-Newton, qui permet de contraindre le modèle cosmologique standard.
Os presentamos una curiosa iniciativa que ha combinado la creatividad de científicos, periodistas y publicistas: un spray anti monstruos que evita los miedos de los niños a la oscuridad, los fantasmas, dormir solo... También os contamos detalles sobre la placa tectónica de las Filipinas. TITULAR 1. La estación de la Agencia Espacial Europea en Cebreros, Ávila, se une al homenaje a Stephen Hawking La Agencia Espacial Europea ha emitido desde la estación abulense la música del compositor griego Vangelis en honor a Stephen Hawking. Los científicos han dirigido la antena hacia el agujero negro más cercano conocido mientras se enterraban las cenizas de Hawking. En la grabación también se podía escuchar la voz del científico británico. TITULAR 2: El secreto de la longevidad del roble podría residir en las mutaciones de su sistema inmunitario. Científicos de la Universidad de Burdeos y de la Universidad de Gerona han estudiado el genoma del roble común y han descubierto que la expansión de genes resistentes a enfermedades es el secreto de árboles como el roble. Gracias a duplicaciones selectivas de genes, estas plantas logran sobrevivir a nuevas plagas y enfermedades. TITULAR 3: Curiosity capta imágenes de la tormenta de polvo en Marte Curiosity ha estado estudiando el suelo marciano en el cráter Gale del planeta rojo durante la tormenta que ha dejado a Opportunity fuera de juego. Este fenómeno ha ofrecido una ventana de oportunidad sin precedentes para analizar apreguntas como ¿por qué algunas tormentas de polvo marcianas duran meses y se vuelven masivas, mientras que otras se mantienen pequeñas y duran solo una semana? TITULAR 4: Un observatorio de rayos X encuentra material intergaláctico desaparecido Solo un 5% de nuestro universo está constituido por materia ‘ordinaria'. Hace décadas que los astrónomos buscan dónde se esconden en el cosmos más de la mitad de los bariones, partículas como los neutrones y protones, y con la ayuda del observatorio espacial XMM-Newton de rayos X los han encontrado. Un grupo de señales de oxígeno en el gas intergaláctico caliente entre nosotros. TITULAR 5: Gales detecta un caso de viruela bovina, una enfermedad muy frecuente… en el s.XVIII Un adolescente que reside entre la frontera de Wrexham-Cheshire (Reino Unido) ha sido diagnosticado con viruela bovina, una enfermedad muy frecuente durante el siglo XVIII, pero cuya incidencia ha disminuido de forma drástica —según los especialistas en salud pública de Gales, el último caso se habría producido en la región hace 10-15 años—, manteniéndose aislado en gatos o elefantes. TITULAR 6: Antes de nacer las estrellas ya saben dónde brillarán La astronomía ha observado que en los cúmulos las estrellas más masivas se encuentran más cercanas. ¿Esto sucede antes o después de que se conviertan en estrellas? Un estudio responde a esta pregunta determinando que cuando se forman grandes cúmulos las estrellas más masivas se concentran entre ellas en base a una formación primigenia estructurada de forma previa.
A new study using Chandra and XMM-Newton data reveals that the auroras at Jupiter's poles behave independently.
"Imaginez chausser des lunettes qui vous font voir le monde… autrement ! C’est ce qu’ont fait les astronomes avec des ballons, des fusées et aujourd’hui des télescopes spatiaux, pour se libérer de la barrière de l’atmosphère. L’astronomie des rayons X dévoile un univers plus violent, plus énergétique qu’en lumière visible. Avec ces lunettes, les scientifiques explorent des régions de l’espace très chaudes dans lesquelles règnent des conditions extrêmes. Ce sont les centres des galaxies, les supernovae – ces étoiles qui explosent et fabriquent la matière qui nous compose - , ou encore les voisinages des trous noirs. A l’aide des observations du satellite européen XMM-Newton et de l’américain Chandra visite guidée des feux d’enfer du cosmos, au cœur de ces creusets stellaires et galactiques. En 3 parties - partie 3 Rediffusion de l'émission de 2007
"Imaginez chausser des lunettes qui vous font voir le monde… autrement ! C’est ce qu’ont fait les astronomes avec des ballons, des fusées et aujourd’hui des télescopes spatiaux, pour se libérer de la barrière de l’atmosphère. L’astronomie des rayons X dévoile un univers plus violent, plus énergétique qu’en lumière visible. Avec ces lunettes, les scientifiques explorent des régions de l’espace très chaudes dans lesquelles règnent des conditions extrêmes. Ce sont les centres des galaxies, les supernovae – ces étoiles qui explosent et fabriquent la matière qui nous compose - , ou encore les voisinages des trous noirs. A l’aide des observations du satellite européen XMM-Newton et de l’américain Chandra visite guidée des feux d’enfer du cosmos, au cœur de ces creusets stellaires et galactiques. En 3 parties - partie 2 Rediffusion de l'émission de 2007
"Imaginez chausser des lunettes qui vous font voir le monde… autrement ! C’est ce qu’ont fait les astronomes avec des ballons, des fusées et aujourd’hui des télescopes spatiaux, pour se libérer de la barrière de l’atmosphère. L’astronomie des rayons X dévoile un univers plus violent, plus énergétique qu’en lumière visible. Avec ces lunettes, les scientifiques explorent des régions de l’espace très chaudes dans lesquelles règnent des conditions extrêmes. Ce sont les centres des galaxies, les supernovae – ces étoiles qui explosent et fabriquent la matière qui nous compose - , ou encore les voisinages des trous noirs. A l’aide des observations du satellite européen XMM-Newton et de l’américain Chandra visite guidée des feux d’enfer du cosmos, au cœur de ces creusets stellaires et galactiques. En 3 parties - partie 1 Rediffusion de l'émission de 2007
This week we talk about Trappist-1 and it's seven planets, Winston Churchill's lost exoplanet paper, Michael Foale, the UK's working Spaceport by 2020, XMM-Newton and the brightest pulsar, and all the latest news in space exploration and astronautics. Support Space exploration and join the BIS at www.bis-space.com the oldest space advocacy organisation in the world. Subscribe to the Interplanetary podcast on iTunes itunes.apple.com/gb/podcast/inter…ast/id1097505801 Click subscribe to the Interplanetary podcast on Stitcher www.stitcher.com/podcast/interplanetary-podcast Hosts: Matt Russell and Jamie Franklin Music: Matt Russell / Iam7 Additional Narration: George Russell www.interplanetary.org.uk @interplanetypod
Le pulsar X le plus brillant vient d'être débusqué dans la galaxie NGC 5907 située à 50 millions d'années-lumière. Sa luminosité est plus de 1000 fois plus forte que ce qui paraissait possible pour un pulsar de ce type. Cette découverte a été effectuée par le télescope européen XMM-Newton.
Conversación sobre las misiones de astronomía de la Agencia Espacial Europea, ¿cómo operar un telescopio en es espacio?¿Qué son los datos científicos? Hablamos sobre las misiones Gaia, XMM Newton, Hershel, Planck, etc. El invitado, Bruno Merin, es el coordinador científico de los archivos de astronomía de la Agencia Espacial Europea. También hablamos acerca de exoplanetas, de nuestro sistema solar e incluso de ExoMars y su problema de aterrizaje en Marte.
Deux objets d'un nouveau type viennent d'être découverts par une équipe internationale d'astronomes. Ces objets produisent des intenses éruptions en rayons X qui augmentent de près d'un facteur 100 en seulement 1 minute puis retournent à leur niveau initial après une heure. Ces sources X ultralumineuses inconnues ont été observées avec Chandra et XMM-Newton et leur découverte fait l'objet d'une publication dans la revue Nature cette semaine.
First discovered in observations from Chandra and XMM-Newton over a decade ago, this object has some interesting properties.
Voilà une belle découverte qu'on n'attendait pas : la halo de gaz chaud de notre galaxie tourne à la même vitesse que le disque galactique. On pensait jusqu'ici qu'il était quasi statique... On doit cette découverte à trois astrophysiciens américains qui ont exploité des données enregistrées par le télescope spatial européen XMM-Newton.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 05/05
Galaxienhaufen sind die größten und massivstem gravitativ gebundenen Objekte im Universum, die Zeit hatten, zu kollabieren und virialisieren. Das Intracluster-Medium (ICM) innerhalb Galaxienhaufen ist ein Plasma, das durch Röntgenstrahlung sichtbar ist. Galaxien in Galaxienhaufen sind durch optische Strahlung zu sehen, sie sind hauptsächlich rot und haben eine niedrige Sternbildungsrate. Neu akkretierte Galaxien können blauere Farben und eine höhere Sternbildungsrate aufweisen und werden durch Interaktion mit dem ICM röter. Wachstum von Galaxienhaufen findet durch sporadisches Verschmelzen mit anderen Galaxienhaufen und Gruppen statt, oder durch gleichmäßige Akkretion von Galaxien aus dem Milieu. Um die Hauptfrage »ergänzen sich Röntgen- und optische Messungen von Galaxienhaufen, oder zeigen sie dasselbe?« zu beantworten, haben wir eine Studie durchgeführt, bei der die Verteilung von Galaxien und ICM in Galaxienhaufen verglichen wurden. Im Besonderen, haben wir untersucht, ob optische Daten zusätzliche Information wegen der dynamische Befindlichkeit von einzelnen Galaxienhaufen liefern, die nicht aus Röntgendaten allein hervorgehen können. Surveys in Röntgen und optischer Strahlung sind in den nächsten Jahrzehnten zu erwarten, die Daten von viel weiteren Gebieten des Universums liefern werden. Diese Daten können, mit den Methoden, die wir hier vorlegen, untersucht werden. Wir benutzten Weitwinkelbeobachtungen des MPG/ESO 2.2 m Telescopes und Röntgenbeobachtungen von XMM-Newton, um die Distribution von Galaxien innerhalb Galaxienhaufen mit der Distribution des ICM zu vergleichen. Wir haben gefunden, dass die 1D Radialdistribution der roten Galaxien zu der des ICM zusammenpasst, aber die blauen Galaxien folgen einem flacheren Profil. Mit 2D Abbildungen der Galaxienhaufen, haben wir gefunden dass die roten Galaxien sehr ähnlich verteilt sind, wie das ICM, aber fast jeder Galaxienhaufen hat unvirialisierte rote Subklumpen. Blaue Galaxien anderseits haben zu wenig Zeit zum virialisiern bevor sie rot werden, weil sie ihre sternbildendes Gas innerhalb einer Übergangszeit durch ICM-Staudruckstripping verliern. Röntgenbeobachtungen sind besser für die Bestimmung des Verschmelzungsverlaufes von Galaxienhaufen, weil sie die Kennzeichen von Verschmelzung für eine kürzere Zeit zeigen. Wir haben mehrere Subklumpen von roten Galaxien entdeckt, die scheinen auf einfallenden Trajektorien in Galaxienhaufen zu sein und noch merkliche Mengen von Röntgenemittierendem Gas zu haben.
ASTRO-H : sous ce nom qui évoque un dessin animé japonais, se cache l'un des plus beaux outils des astrophysiciens. ASTRO-H est un télescope spatial de nouvelle génération, spécialisé dans l'observation des rayons X. Il va compléter, voire supplanter, dès l'année prochaine les trois principaux télescopes à rayons X en activité que sont les américains Chandra et NUSTAR et l'européen XMM-Newton.
A team of astronomers has used Chandra X-ray Observatory and XMM-Newton to study a large group of galaxy clusters with a surprising result.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 04/05
The morphological analysis of galaxy clusters in X-rays allows a reliable determination of their dynamical state. Substructures on (sub-)Mpc scale influence the gravitational potential of a cluster and manifest themselves in the X-ray surface brightness distribution as secondary peaks or overall irregular shape. They lead to deviations from the hydrostatic equilibrium and spherical shape, two assumptions which are widely used in galaxy cluster studies to derive global astrophysical properties. Analyzing the X-ray morphology of clusters thus yields valuable information, provided that the employed substructure measures are well-tested and well-calibrated. In this work, the X-ray morphology of galaxy clusters is quantified using three common substructure parameters (power ratios, center shift and the asymmetry parameter), which are subsequently employed to study the disturbed cluster fraction as a function of redshift. To ensure a reliable application of these substructure parameters on a variety of X-ray images, a detailed parameter study is conducted. It focuses on the performance and reliability of the parameters for varying data quality using simulated and observed X-ray images. In particular, when applying them to X-ray images with low photon counts such as observations of distant clusters or survey data, it is important to know the characteristics of the parameters. Comparing the three substructure measures, the center shift parameter is most robust against Poisson noise and allows a reliable determination of the clusters' dynamical state even for low-count observations. Power ratios, especially the hexapole P3/P0, and the asymmetry parameter, on the other hand, are severely affected by noise, which results in spuriously high substructure signals. Furthermore, this work presents methods to minimize the noise bias. The results of the parameter study provide a step forward in the morphological analysis of high-redshift clusters and are employed in the framework of this thesis to quantify the evolution of the disturbed cluster fraction. The sample used for this analysis comprises 78 low-z (z < 0.3) and 51 high-z (0.3 < z < 1.08) galaxy clusters with varying photon statistics. The low-redshift objects were observed with the XMM-Newton observatory, contain a high number of photon counts and are part of several well-known and representative samples. For z > 0.3, the high-redshift subsets of the 400d2 and SPT survey catalog are used. These objects were mainly observed with the Chandra observatory and have low photon counts. To ensure a fair comparison, which is independent of the data quality, the photon statistics of the low- and high-redshift observations are aligned before performing the morphological analysis. In agreement with the hierarchical structure formation model, a mild positive evolution with redshift, i.e. a larger fraction of clusters with disturbed X-ray morphologies at higher redshift, is found. Owing to the low photon counts and small number of high-redshift observations, the statistical significance of this result is low. For two of the three substructure parameters (power ratios and center shift) the findings are also consistent within the significance limits with no evolution, but a negative evolution of the disturbed cluster fraction can be excluded for all parameters.
Das Röntgen-Weltraumteleskop XMM-Newton ist nicht nur eine wichtige Mission für die Wissenschaft, sie ist auch eine der technisch erfolgreichsten und langlebigsten Missionen der ESA überhaupt. Obwohl der Satellit jetzt schon länger im Betrieb ist als geplant, könnten bestimmte Maßnahmen die Laufzeit sogar noch deutlich verlängern. Mit Hilfe von XMM-Newton können Wissenschaftler mit sehr zielgerichtet und mit hoher Präzision ferne Sterne und Galaxien im Frequenzbereich der Röntgen-Strahlung untersuchen. Nachdem der Satellit ROSAT als Pionier der Röntgenastronomie eine Landkarte der Röntgenstrahlung im Universum geliefert hat, hebt XMM-Newton die Forschung in diesem Bereich auf eine neue Stufe. Im Gespräch mit Tim Pritlove berichtet der für den Flugbetrieb von XMM-Newton zuständige Spacecraft Operations Manager Marcus Kirsch über Ziele und Aufgaben des Röntgen-Weltraumteleskops und erzählt auch von den großen Herausforderungen, vor dem das Team stand, als der Satellit einmal eine Woche nicht mehr zu erreichen war.
AstronomyCast 276: XMM Newton, by Fraser Cain & Dr. Pamela Gay
Observational constraints on the average radial distribution profile of AGN in distant galaxy clusters can provide important clues on the triggering mechanisms of AGN activity in dense environments and are essential for a completeness evaluation of cluster selection techniques in the X-ray and mm wavebands. The aim of this work is a statistical study with XMM-Newton of the presence and distribution of X-ray AGN in the large-scale structure environments of 22 X-ray luminous galaxy clusters in the redshift range 0.9 < z less than or similar to 1.6 compiled by the XMM-Newton Distant Cluster Project (XDCP). To this end, the X-ray point source lists from detections in the soft band (0.35-2.4 keV) and full band (0.3-7.5 keV) were stacked in cluster-centric coordinates and compared to average background number counts extracted from three independent control fields in the same observations. A significant full-band (soft-band) excess of similar to 78 (67) X-ray point sources is found in the cluster fields within an angular distance of 8' (4 Mpc) at a statistical confidence level of 4.0 sigma (4.2 sigma), corresponding to an average number of detected excess AGN per cluster environment of 3.5 +/- 0.9 (3.0 +/- 0.7). The data point towards a rising radial profile in the cluster region (r < 1Mpc) of predominantly low-luminosity AGN with an average detected excess of about one point source per system, with a tentative preferred occurrence along the main cluster elongation axis. A second statistically significant overdensity of brighter soft-band-detected AGN is found at cluster-centric distances of 4'-6' (2-3 Mpc), corresponding to about three times the average cluster radius R-200 of the systems. If confirmed, these results would support the idea of two different physical triggering mechanisms of X-ray AGN activity in dependence of the radially changing large-scale structure environment of the distant clusters. For high-z cluster studies at lower spatial resolution with the upcoming eROSITA all-sky X-ray survey, the results suggest that cluster-associated X-ray AGN may impose a bias in the spectral analysis of high-z systems, while their detection and flux measurements in the soft band may not be significantly affected.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 04/05
The aim of this thesis is to characterize the properties of the integrated spectrum of active galactic nuclei(AGNs), such as the ubiquity of the Fe Kα emission in AGNs, the dependence of the spectral parameters(e.g. the power law photon index and the Fe Kα equivalent width etc.) on the X-ray luminosity and redshift, and mean properties (including the line profile) of the Fe Kα line which can be addressed via stacking in the source rest-frame. I selected 2646 point sources observed with XMM-Newton at high galactic latitude (|BII| > 25 degrees) and with the sum of EPIC-PN and EPIC-MOS 0.2–12 keV counts greater than 1000. Redshifts were obtained for 919 sources from the Nasa’s Extragalactic Database. In order to prepare a clean sample, I retained only reliable sources (those for which the detection and the spectral products do not show obvious problems). I also excluded sources classified as HII regions, groups/clusters, star-forming/starburst galaxies. The final sample consists of 507 AGNs. To examine the ubiquity of the Fe Kα emission in AGNs and the dependence of the spectral parameters on the X-ray luminosity and redshift, I employed the observed-frame stacking technique, in which individual source spectra were summed in the observed-frame to compute the integrated spectra in different redshift and luminosity bins over the range 0 < z < 5. Detailed analysis of these spectra used appropriately normalized background spectra and exposure time weighted response and ancillary files. I find that the narrow Fe Kα line at 6.4 keV is significantly detected up to z = 1. The line equivalent width decreases with increasing the X-ray luminosity in the 2–10 keV band (“Iwasawa-Taniguchi effect”). The anticorrelation is characterized by the relation log(EW_Fe) = (1.66 ± 0.09) + (−0.43 ± 0.07) log(LX,44), where EW_Fe is the rest-frame equivalent width of the neutral Fe Kα line in eV and LX,44 is the 2–10 keV X-ray luminosity in units of 10^44 erg/s. The equivalent width is nearly independent of redshift up to z ∼ 0.8 with an average value of 101 ± 40 (rms dispersion) eV in the luminosity range 43.5 ≤ log LX ≤ 44.5. This analysis also confirms the hardening of the spectral indices at low luminosities, implying a dependence of obscuration on luminosity. To derive the mean properties of the Fe Kα line in the source rest-frame, I refined the final sample of 507 AGNs and selected 248 AGNs with the EPIC-PN net 2–10 keV rest-frame counts ≥200 and power law photon indices in the range 1.5–2.2. I computed the integrated spectrum of these 248 AGNs in the source rest-frame using two different rest-frame stacking procedures. I carried out a detailed spectral analysis of these integrated spectra using various models comprising simple/complex continuum and Fe Kα line components. I find that the average Fe Kα line profile in our sample is best represented by a combination of a narrow and a broad line. The equivalent widths of the narrow and broad components are ∼30 eV and ∼100 eV, respectively. The broad line parameters such as its shape, equivalent width and its detection significance in the integrated spectrum of the 248 AGNs are observed to be very sensitive to the assumed continuum and adopted stacking method. However, despite having a well-defined sample with reasonable statistics (net counts ∼ 198000) in the integrated spectrum, I do not detect a clear extended red-wing, and the measured equivalent width of the broad feature is always lower than 170 eV, implying that most black holes are not maximally rotating.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 03/05
This dissertation presents the analysis of a large and deep XMM-Newton survey of the second large Local Group spiral galaxy M 31. The survey observations, taken between June 2006 and February 2008, together with re-analysed archival observations from June 2000 to July 2004 cover, for the first time, the whole D25 ellipse of M 31 with XMM-Newton down to a limiting luminosity of ~10^35 erg/s in the 0.2-4.5 keV band. The main goal of the thesis was a study of the different source populations of M 31 that can be observed in X-rays. Therefore a catalogue was created, which contains all 1948 sources detected in the 0.2-12.0 keV range. 961 of these sources were detected in X-rays for the first time. Source classification and identification was based on X-ray hardness ratios, spatial extent of the sources, and by cross correlating with catalogues in the X-ray, optical, infrared and radio wavelengths. An additional classification criterion was the long-term temporal variability of the sources in X-rays. This variability allows us to distinguish between X-ray binaries and active galactic nuclei. Furthermore, supernova remnant classifications of previous studies that did not use long-term variability as a classification criterion, could be validated. Including previous Chandra and ROSAT observations in the long-term variability study allowed me to detect additional transient or at least highly variable sources, which are good candidates for being X-ray binaries. Fourteen of the 40 supersoft source (SSS) candidates correlated with optical novae and therefore can be considered the supersoft emission of the optical novae. Among them is the first nova/SSS detected in a globular cluster of M 31. Correlations with previous ROSAT and Chandra studies revealed that only three SSSs are visible for at least one decade. This result underlines the strong long-term variability found for the class of SSSs. In addition the correlations demonstrated that strict selection criteria have to be applied to securely select SSSs. An investigation of the spatial distribution of the 25 supernova remnants (SNRs) and 37 SNR candidates showed that many of these sources are consistent with the location of the 10 kpc dust ring and other star forming regions in M 31. This connection between SNRs and star forming regions implies that most of the remnants are from type II supernovae. The brightest sources of M 31 belong to the class of X-ray binaries (XRBs). Ten low mass XRBs (LMXBs) and 26 LMXB candidates were identified based on their temporal variability. In addition 36 LMXBs and 17 LMXB candidates were identified due to correlations with globular clusters and globular cluster candidates. From the LMXBs located in globular clusters one is a black hole candidate and another a neutron star candidate. From optical and X-ray colour-colour diagrams, possible high mass XRB (HMXB) candidates were selected. Two of these candidates have an X-ray spectrum as is expected for an HMXB containing a neutron star primary. To investigate the logN-logS relations of sources in the field of M 31, a catalogue of sources detected in the 2.0-10.0 keV energy range was created. The slope of the logN-logS relation for the whole galaxy is consistent with the expectation for spiral galaxies (Colbert et al. 2004). Subtracting the background logN-logS relation, the region beyond the D25 ellipse still contains about 13 sources/deg^2 of M 31 with fluxes above the completeness limit of ~3.2x10^{-14} erg/cm^2/s (~2.3x10^36 erg/s at the distance of M 31). The radial dependence of the source distribution in M 31's disc can be well fitted with an exponential profile, for limiting fluxes of ~3.2x10^{-14} erg/cm^2/s and 10^{-13} erg/cm^2/s (~7.3x10^36 erg/s). About 60% of all sources with fluxes above 3.2x10^{-14} erg/cm^2/s are background sources. While the contribution of background sources lies at ~20% in the inner disc region, the fraction increases to >~80% in the outer areas of M 31. For the dust ring region, the slope of the logN-logS relation as well as the number of sources and their dependence on the star forming rate were consistent with the universal logN-logS relation predicted from theoretical considerations of HMXBs (Grimm et al. 2003). These findings propose that the dust ring region contains a population of HMXBs. A comparison of the number of X-ray binaries (XRBs) obtained from the logN-logS study to the ones listed in the source catalogue showed that many XRBs detected in the logN-logS study with fluxes between 10^{-13} erg/cm^2/s and 3.2x10^{-14} erg/cm^2/s, or (independent from the flux) those XRBs located in the inner disc of M 31, remain without XRB classification in the source catalogue. The results presented in this thesis gave us deeper insights in the properties of the population of X-ray sources in M 31. Nevertheless, about 65% of all sources detected in the field of M 31 can be classified as ``hard" sources only, i.e. it is not possible to decide whether these sources are X-ray binaries or Crab-like supernova remnants in M 31, or active galactic nuclei. Deeper observations in the X-ray and at other wavelengths are needed to classify these sources.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 02/05
Investigating X-ray luminous galaxy clusters at high redshift (z>~1) provides a challenging but fundamental constraint on evolutionary studies of the largest virialized structures in the Universe, the baryonic matter component in form of the hot intracluster medium (ICM), their galaxy populations, and the effects of the mysterious Dark Energy. The main aim of this thesis work is to establish the observational foundation for the XMM-Newton Distant Cluster Project (XDCP). This new generation serendipitous X-ray survey is focused on the most distant galaxy clusters at z>1, based on the selection of extended X-ray sources, their identification as clusters and redshift estimation via two-band imaging, and their final spectroscopic confirmation. As a first step, I have analyzed 80 deg^2 (469 fields) of deep XMM-Newton archival X-ray data with a new pipeline processing system and selected almost 1000 extended sources as galaxy cluster candidates, 75% of which could be identified as clusters or groups at z
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 02/05
Tue, 27 Nov 2007 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/8987/ https://edoc.ub.uni-muenchen.de/8987/1/Hui_Chung-Yue.pdf Hui, Chung Yue ddc:500, ddc:530, Fakultät für Physik
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 02/05
The study of the formation and growth of cosmic structures is one of the most fascinating and challenging fields of astrophysics. In the currently favoured cosmological model, the so-called LCDM cosmogony, dark matter structures grow hierarchically, with small clumps forming first at very early epochs. The merging of these dark matter halos in the following evolution leads to the formation of more massive objects with time, ultimately resulting in a complex cosmic web composed of filaments of dark matter and galaxies, rich galaxy clusters, and voids in between. While we have some knowledge how these dark matter structures evolve with cosmic time, the relationship between the "dark" and the "luminous" content of the Universe is still far from being fully understood and it poses many puzzling questions, both for observational and theoretical investigations. Galaxy clusters, the largest virialized objects in the Universe, are especially interesting for cosmological studies because they are ideal laboratories to study the physical processes relevant in structure formation, like those that shape the properties of galaxies, the intergalactic and intracluster media, and the active galactic nuclei (AGN) that originate from super-massive black holes (BHs) in cluster centres. The study of clusters is remarkably promising right now, both because of the wealth of new data from X-ray telescopes such as XMM-Newton and Chandra or from optical surveys such as SDSS, and also due to the increasing power of cosmological simulations as a theoretical tool. The latter can track the growth of cosmological structures far into the highly non-linear regime, and have recently become faithful enough to include for the first time physical processes such as AGN activity and its effect on galaxy evolution. Therefore the aim of this Thesis was to incorporate AGN heating process in fully self-consistent cosmological simulations of structure formation, and to constrain the relevance of this feedback mechanism for galaxy and galaxy cluster formation and evolution.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 02/05
Gegenstand der vorliegenden Arbeit war die Entwicklung und Analyse einer neuartigen abbildenden Optik mit dem Ziel, das räumliche Auflösungsvermögen im Röntgenband zwischen 1 keV und 20 keV auf wenigstens 1 mas zu verbessern. Aufgrund ihrer hohen Toleranz gegenüber Fertigungsfehlern besitzen transmissive Linsen das prinzipielle Potential zur beugungsbegrenzten Abbildung. Je nach Ausführung dürfen Abweichungen von mehreren 100 – 1000 nm gegenüber der idealen Formgebung auftreten. Im Gegensatz zur absorptionsbehafteten, massiven Version weist die diffraktive, profiloptimierte Fresnel-Linse auch in höheren Ordnungen eine Beugungseffizienz zwischen 40% und 100% auf. Der Kontamination der Bildebene durch Streustrahlung benachbarter Ordnungen ist ggf. durch eine ausreichende Zentralobstruktion zu begegnen, deren Radius dem doppelten Detektor-Halbmesser entspricht. Strahlenoptische Berechnungen weisen diffraktive Linsen als vergleichsweise tolerant gegenüber Aberrationen sphärischen wie winkelabhängigen Ursprungs aus. Typische Öffnungsverhältnisse f von (10^4 – 10^5) erlauben Verkippungen von bis zu 1°. Die Lichtstärke, definiert als Produkt von effektiver Sammelfläche und Bandpass, skaliert für Fresnel-Linsen ausschließlich linear mit der Brennweite, bleibt allerdings selbst für Fokaldistanzen von wenigen 100 km auf wenige cm^2 keV beschränkt. Mit der segmentierten Apertur lässt sich jedoch die Lichtstärke erhöhen, ohne das Prinzip der beugungsbegrenzten Abbildung und den klassischen Einzelfokus aufzugeben. Bei einer Ortsauflösung von 1 mm erreichen derlei inkohärent operierende Objektive eine Lichtstärke von über 1000 cm^2 keV. Unter Einsatz eines dem diffraktiven Bandpass adäquaten Kristallspektrographen bedarf es dazu tendenziell großer Radien von rund 10 m und typischer Brennweiten im Bereich einiger 100 km. Ferner wurden im Rahmen dieser Arbeit mutmaßlich erstmals Multiband-Objektive zur wissenschaftlich vorteilhaften Simultanfokussierung von bis zu drei Energiebändern implementiert. Bestehend aus Partial-Linsen unterschiedlicher Gitterfrequenz, erweisen sie sich der Monoband-Ausführung als bzgl. Auflösung, Brennweite und Lichtstärke prinzipiell ebenbürtig. Die Dispersionskorrektur mittels eines additiven refraktiven Linsenprofils erweitert den spektralen Bandpass auf dem Detektor direkt zugängliche 100 eV oder mehr. Mit der Absorption geht eine reduzierte Sammelfläche für kompakte Hybridlinsen einher. Trotzdem resultiert unter Beibehalt der Winkelauflösung für Materialien wie Li oder Be jenseits weniger keV eine gegenüber dem diffraktiven Analogon verbesserte Lichtstärke. Optimiert bzgl. Material und Energie, steigern derartige Achromaten die Nachweisempfindlichkeit um das bis zu 40-fache – entsprechend einer Lichtstärke von rund 100 cm^2 keV bei Brennweiten von 100 km oder mehr. Wiederum segmentiert, wirkt sich die Absorption vergleichsweise geringfügig auf die Winkelauflösung aus, die Sensitivität des dispersionskorrigierten Objektivs steigt gegenüber der diffraktiven Version unter sonst gleichen Bedingungen jetzt um bis zu zwei Größenordnungen. Bei gegebener Ortsauflösung von 0.75 mm ergeben sich für Li oberhalb von 6 keV und Be jenseits von 8 keV optimierte Lichtstärken zwischen 10^3 und 10^4 cm^2 keV, vergleichbar jenen der gegenwärtig aktiven Observatorien Chandra und XMM-Newton. Die Winkelschärfe skaliert invers mit der Fokaldistanz, für höchstens 1 mas ergeben sich Brennweiten von rund 100 – 1000 km. Plankonvexe Profile werden den zumeist kleinen Krümmungsradien der refraktiven Komponente hinsichtlich ihrer Aberrationen dritten Grades im allgemeinen nicht gerecht. Hingegen reduziert das aplanatische, nahezu bikonvexe Profil sowohl sphärische als auch winkelabhängige Bildfehler auf ihre diffraktiven Beiträge und legt daher im segmentierten Hybrid-Achromaten die Konstruktion symmetrischer, prismen-ähnlicher Bausteine nahe. Die mit der kohärenten Profilreduktion einhergehende Interferenz erfordert den Einsatz abbildender Spektrographen mit einer Auflösung nahe 1 eV. Vor allem optisch schwache Materialien wie z.B. Polycarbonat (C16H14O3) profitieren von der erhöhten Transparenz bei konstanter Orts- und Winkelauflösung; im Energieintervall zwischen 9 keV und 12 keV optimierte Beispielkonfigurationen liefern eine Lichtstärke von wenigstens rund 1000 cm^2 keV. Modelle aus Li und Be erreichen oberhalb von 4 keV bzw. 7 keV eine ähnliche Leistungsfähigkeit. Multiband-Hybridsysteme gestatten anders als diffraktiv simultan fokussierende Objektive die Detektion mittels konventioneller CCD. Die aus Li und Be bestehenden Konfigurationen bilden jeweils zwei Energiebänder gleichzeitig ab und erweisen sich bei einer Ortsauflösung im Sub-mm-Bereich sowie Brennweiten von wenigen 100 km als eine hinsichtlich ihrer Gesamt-Lichtstärke konkurrenzfähige Alternative zum Monoband-Teleskop: Man erhält im Idealfall 4000 cm^2 keV bis 7000 cm2 keV. Dialytische Modell-Teleskope, deren refraktive Komponente von der diffraktiven räumlich separiert ist, bieten zum einen die Option einer über mehrere keV durchstimmbaren, dispersionskorrigierten Optik. Unter Variation des Linsenabstandes ergibt sich ein nutzbares Energieintervall zwischen 6 keV und 14 keV. Die Lichtstärke nimmt dabei von 1000 cm^2 keV in zweiter bis auf 4000 cm^2 keV in dritter Dispersionsordnung zu. Kompakte Dialyten mit Durchmessern von 1 m besitzen das Potential zu einer Winkelauflösung von wenigen 10 Mikrobogensekunden sowie einer Lichtstärke von mehreren 1000 cm^2 keV. Der spektrale Bandpass solcher Modelle beträgt rund 1 keV oder mehr. Abschätzungen zum Signal-Rausch-Verhältnis zeigen, dass bei ausreichender Abschirmung des Detektors und moderatem Quellfluss mit einer signal- oder photonenlimitierten Beobachtungssituation zu rechnen ist. Dies gilt angesichts des diskreten Röntgen-Hintergrundes weitgehend auch dann, wenn mehrere Teleskope parallel geschaltet werden. Ergänzende Betrachtungen zu potentiellen astronomischen Beobachtungsobjekten zeigen, dass Koronae benachbarter Sterne, Jets von Röntgen-Doppelsternen und aktiven Galaxienkernen, Supernova-Überreste bzgl. ihrer Ausdehnung einer Auflösung von 1 mas genügen. Von großem Interesse dürften im Hinblick auf künftige Gravitationswellen-Experimente ferner Betrachtungen verschmelzender, supermassiver Schwarzer Löcher sein.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 02/05
In this thesis we analysed the deepest XMM-Newton observations of the Chandra Deep Field South and the Lockman Hole. These two reference fields for studies of different X-ray background source classes, provide a unique opportunity to study physical and evolutionary properties of distant normal and active galaxies, clusters of galaxies and even faint Galactic stars using statistically significant samples. The main goal of the work was a further improvement of the knowledge about X-ray properties of AGN and galaxies in the distant Universe using the statistical treatment of these large samples of detected sources.
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 02/05
Thu, 27 Oct 2005 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/4628/ https://edoc.ub.uni-muenchen.de/4628/1/Zhang_Yu-Ying.pdf Zhang, Yu-Ying ddc:530, ddc:500, Fa
Fakultät für Physik - Digitale Hochschulschriften der LMU - Teil 02/05
The X-ray properties of five Narrow-line Seyfert 1 galaxies (NLS1) are analysed and presented in this dissertation. The data were collected with XMM-Newton, and to date, are of the highest quality ever obtained. Themes which have evolved and appear fundamental in understanding NLS1 are: near- or super-Eddington accretion by a "small" supermassive black hole, partial covering, and reflection. Most of the objects presented in this dissertation can adopt these principles. The main results of this work are as follow. Two observations of 1H0707-495 and one observation of IRAS 13224-3809 show sharp, spectral drops above ~7 keV (Chapters 2 and 4). The sharpness of the features, and absence of iron fluorescent emission and Kbeta UTA absorption, challenge the possibility that the drops originate from photonionisation. If partial covering from a neutral absorber is adopted then outflows on the order of 0.05-0.15 c are required. On the other hand, if the sharp drops are associated with the blue wings of relativistically broadened Fe Kalpha lines (Chapters 2 and 5) then the interpretation requires light bending close to the black hole to explain the large equivalent widths and variability properties. Both interpretations require an iron overabundance (3-10 times solar), suggesting that supersolar metallicities may simply be characteristic of NLS1, probably due to strong starburst activity close to the nucleus. The general variability properties of NLS1 remain elusive, but advances have been made. All of the Seyferts and quasars discussed here showed rapid and extreme variability at some point during the observations. IRAS 13224-3809 exhibited some of the most remarkable variability (Chapter 3). Lags between the hard and soft energy bands were detected, suggesting that fluctuations at low energies instigated variability at higher energies. However, closer inspection revealed that the lags alternate: sometimes the hard band follows, while at other times it leads. Spectral variability was determined to be correlated with flux variations, but more interestingly was the finding that the spectral variability also lagged flux variations, resulting in flux-induced spectral variability. For over 120 ks (spread over two observations), 1H0707-495 persistently displayed flux variations by at least a factor of four. During the first observation, when 1H0707-495 was in its lowest flux state ever recorded, there was no significant spectral variability. The second observation, when the source was in a higher flux state, revealed strong spectral variability. Flux and spectral fluctuation were never found to be significantly correlated (Chapter 4). The quasar, PHL 1092, exhibited some of the most striking variability considering its high luminosity (Chapter 7). Indeed, an estimate of its radiative efficiency was in excess of that expected from a Schwarzschild black hole. Interestingly, the variability appeared to be entirely concentrated in the soft-excess, with the power-law component appearing quiescent. The closest example of class behaviour seen in the variability of the group was displayed by the two quasars I Zw 1 and NAB 0205+024 (Chapters 6 and 8, respectively). Both objects exhibited a hard X-ray flare which was concentrated at energies higher than ~2 keV and accompanied by spectral variability. A scenario in which the hard X-ray flare originates in the accretion disc corona, and then irradiates the disc itself seem most applicable here. I Zw 1 has been defined as the prototype NLS1 based on its optical properties. In the X-rays it appears anything but prototypical. Significant low-energy intrinsic absorption, a weak soft-excess, and evidence for multiple iron emission lines suggest that other processes are at work (Chapter 6). PHL 1092 exhibited deviations from a power-law fit in the 2-10 keV band (Chapter 7). The difference could be interpreted as an emission line enhanced by light bending close to a Kerr black hole. The complex variability could also be understood in terms of light bending; however, partial covering could not be definitively dismissed due to the modest-quality data. NAB 0205+024 portrayed a broad emission feature at ~5.8 keV which was inconsistent with expected emission from elements in that spectral region. The feature could be described as neutral iron emitted from a narrow annulus on the disc (Chapter 8). The presence of the hard X-ray flare, steep power-law slope, and redshifted iron line provide circumstantial support for the "thundercloud model" proposed by Merloni & Fabian (2001).
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