Podcasts about Sloan Digital Sky Survey

Have you ever wondered how data from the telescopes that peer into our universe ends up in the hands of the astronomers who interpret it? To find out, Dr. Charles Liu and co-host Allen Liu welcome Robert Sparks, currently from the NSF's NOIRLab, but previously Fermi Lab and the Sloan Sky Survey. The National Optical InfraRed Astronomy Research Lab is responsible for operating the National Science Foundation's ground based, nighttime optical and near infrared astronomy for the United States. Robert describes their Community Science Data Center which ties all the data from all their telescopes together to make it available for astronomers around the world to use in their research. As always, though, we start off with the day's joyfully cool cosmic thing, a project coming out of NOIRLab called 88 Constellations. Robert, who spearheaded the project, explains how the final, incredibly detailed image combined classic constellations and new, modern additions and covered the entire sky. One of his favorite parts of the project? Learning about the constellations in the southern hemisphere that doesn't get to see that often, like the Southern Cross. Chuck, Allen and Robert share some of their experiences stargazing down below, and yes, you know Chuck takes the opportunity to sing us a little Crosby, Stills and Nash! You'll also hear which constellation is the smallest in the southern hemisphere, Crux (the Southern Cross) or Delphinus. Then it's on to audience questions. Our first comes from Amirah, who asks, “Blue stars are hotter than red stars, so does that mean blue light bulbs are hotter than red light bulbs? Why would something's color matter about how hot something is?” The short answer: yes (pre-LED, that is!) Robert's long answer involves black body radiation, the electromagnetic spectrum, and red giant carbon stars. Rob shares stories from a career that bridges astronomy and particle physics, including how he got his hands on some original scintillator material from particle detectors at Fermi Lab. (Check out The LIUniverse on Patreon for a scintillating deep dive into…well, scintillation!) The next audience question, from Bryan, is particularly relevant to the discussion: How do astronomy and physics work together? In many, ways, as Robert and Chuck explain. Allen shares the story of the discovery of the element Helium, which was first discovered in the Sun by astronomers, hence its name. You'll also get to hear about Robert's 38-year-long career in improv comedy – and get to watch him (and his cat) act out scenes prompted by Chuck. Finally, we've got one last audience question from Jerry, who says, “I live really far away from the city and I don't have a telescope. What's the best way for me to do astronomy research?” Robert, who grew up in Iowa, tells Jerry about citizen science astronomy projects he can get involved like those at The Zooniverse. You'll hear about how, while working at a program there known as the Galaxy Zoo, a Dutch schoolteacher named Hanny Van Arkel discovered a weird light echo from a quasar that is now known as “Hanny's Voorwep” (Hanny's Object).   If you'd like to find out more about NOIRLab, the National Optical InfraRed Astronomy Research Lab, check out their website. To keep up with Robert Sparks, you can follow him @halfastro on Bluesky, Threads, Flikr, and Instagram. We hope you enjoy this episode of The LIUniverse, and, if you do, please support us on Patreon.   Credits for Images Used in this Episode: Mauna Kea observatories in Hawaii – Credit: Wikicommons/Alan L. Kitt Peak National Observatory (KPNO) in Arizona. – Credit: KPNO/NOIRLab/NSF/AURA/T. Slovinský 3-D view of the largest structures in the Universe via data from the Sloan Digital Sky Survey. – Credit: NASA/University of Chicago and Adler Planetarium and Astronomy Museum 88 Constellation sky-scape video compiled using images from the best and darkest locations around the globe: Germany (Waldenburg), Spain (Tenerife, La Palma), Namibia and Chile. – Credit: NOIRLab/NSF/AURA/E. Slawik/M. Zamani The constellation Crux (Southern Cross) – Credit: E. Slawik/NOIRLab/NSF/AURA/M. Zamani The constellation Delphinus – Credit: E. Slawik/NOIRLab/NSF/AURA/M. Zamani Illustration of the spectrum of electromagnetic energy, highlighting the portions detected by NASA's Hubble, Spitzer, and Webb space telescopes – Credit NASA Event captured by the Super Kamiokande detector – Credit: Tomasz Barszczak/Super-Kamiokande collaboration Visualization of two colliding galaxies that merge into a single elliptical galaxy over a period spanning two billion years – Credits: NCSA, NASA, B. Robertson, L. Hernquist Helium spectral lines which appear in the visible spectrum at about 400-700 nanometers. – Credit: Creative Commons/ McZusatz Hanny's Voorwep, A Space Oddity – Credit: NASA, ESA, W. Keel (University of Alabama), and the Galaxy Zoo Team   #TheLIUniverse #CharlesLiu #AllenLiu #SciencePodcast #AstronomyPodcast  #NOIRLab #NSF #FermiLab #SloanDigitalSkySurvey #88Constellations #GalaxyZoo #TheZooniverse #blackbodyradiation #electromagneticspectrum #redgiants #carbonstars #particlephysics #scintillatormaterial #particledetectors #scintillation #HannysVoorwep

The Milky Way's origins have puzzled scientists since we first realized its one of countless galaxies in our universe. Find out how scientists have applied information from the Gaia Space Observatory and the Sloan Digital Sky Survey to uncover two of our galaxy's earliest star streams. --- Send in a voice message: https://podcasters.spotify.com/pod/show/david-morton-rintoul/message

In Folge 96 schauen wir wieder mal kurz, was auf dem Mond los ist. Danach diskutieren wir über den Sinn von Weltraumtouristen und die peinliche Tatsache, dass mehr Österreicher im Weltall waren, die “Franz” heißen, als Österreicher, die Österreicherinnen sind. Nach einem kurzen Blick auf eine unerwartete Regenbogenradiogalaxie kommt das Hauptthema an die Reihe: Ruth erzählt von der unerwarteten Entdeckung eines gewaltigen Rings aus Galaxien. Keiner weiß, warum der da ist; er passt in keine unserer kosmologischen Theorien - bzw. höchstens in sehr spekulative die nahelegen, dass unser Universum vielleicht ganz anders ist als wir dachten. Bei Evi geht es um “Rebel Moon” und extrasolare Monde und am Ende diskutieren wir noch kurz über die Deutsche Bahn und Werbung im Podcast. Ach ja! Nominiert uns für den Ö3-Podcast-Award: https://oe3.orf.at/podcastaward/stories/3038638/ Wenn ihr uns unterstützen wollt, könnt ihr das hier tun: https://www.paypal.com/paypalme/PodcastDasUniversum. Oder hier: https://steadyhq.com/de/dasuniversum. Oder hier: https://www.patreon.com/dasuniversum.

This is John Barentine's second appearance and we still haven't exhausted the conversation. How do we solve the light pollution problem? John has some ideas. Use reason and science and, as is John's mission, give people the transformational experience of the night sky. How do we help that happen? By implementing the existing knowledge and technology of the lighting industry that knows how to make that a reality NOW! John Barentine is the Principal Consultant at Dark Sky Consulting, LLC, and was formerly the Director of Public Policy for the International Dark-Sky Association. He earned a Ph.D. in astronomy from the University of Texas at Austin, and previously held staff positions at the National Solar Observatory, Apache Point Observatory, and the Sloan Digital Sky Survey. Throughout his career, he has been involved in education and outreach efforts to help increase the public understanding of science. He is a member of the American Astronomical Society and the International Astronomical Union, and is a Fellow of the Royal Astronomical Society. The asteroid (14505) Barentine is named in his honor. His interests outside of astronomy and light pollution research include history, art and architecture, politics, law and current events. 

EPISODE 1850: In this KEEN ON show, Andrew talks to David J. Helfand, author of THE UNIVERSAL TIMEKEEPERS, about the power of atomic science to unveil the mysteries of unreachably remote time and spaceDavid J. Helfand has served on the Columbia faculty for forty-five years, nearly half that time as Chair of the Department of Astronomy. He has also spent three years at the University of Cambridge, most recently as the Sackler Distinguished Visiting Astronomer, and earlier was a visiting scientist at the Danish Space Research Institute. He has mentored 22 PhD students in high energy astrophysics projects ranging from supernova remnants and neutron stars to the cosmic X-ray background and various areas of radio astronomy. He was a principal in two large radio surveys using the VLA, the FIRST survey of the 10,000-square-degree Sloan Digital Sky Survey footprint, and the MAGPIS survey of the Galactic plane that complements the Spitzer GLIMPSE IR survey. Most of his pedagogical efforts have been aimed at teaching science to non-science majors; in 2004, Columbia's 250th year, he finally succeeded in implementing a vision he began working on in 1982 that has all Columbia first-year students taking his science course, Frontiers of Science, as part of the University's famed Core Curriculum. He received the University's 2001 Presidential Teaching Award and the 2002 Great Teacher Award from the Society of Columbia Graduates.In 2005, he became involved in the effort to create Canada's first independent, non-profit university, Quest University Canada. He was a Visiting Tutor in the University's inaugural semester and served as President & Vice-Chancellor from the Fall of 2008 through 2015. From 2011-2014, Prof. Helfand served as President of the American Astronomical Society and was named a Society Legacy Fellow in 2020. His is currently Chair of the Boards of the American Institute of Physics and of AIP Publishing. He is also a member of the Executive Committee of the Board of Science Counts, an organization formed to communicate with the public about the importance and impact of publicly funded fundamental research. His first book, entitled “A Survival Guide to the Misinformation Age”, provides essential tools any informed citizen must have to combat the tsunami of mis- and dis-information that threatens to drown all rational approaches to personal decision-making and the formation of good public policy.Named as one of the "100 most connected men" by GQ magazine, Andrew Keen is amongst the world's best known broadcasters and commentators. In addition to presenting KEEN ON, he is the host of the long-running How To Fix Democracy show. He is also the author of four prescient books about digital technology: CULT OF THE AMATEUR, DIGITAL VERTIGO, THE INTERNET IS NOT THE ANSWER and HOW TO FIX THE FUTURE. Andrew lives in San Francisco, is married to Cassandra Knight, Google's VP of Litigation & Discovery, and has two grown children.

Watch this episode and you'll feel the hope and positivity emanating from your screen from Aparna and John. Michael discusses, with Aparna and John, humanity's lost connection with the sky, forgotten sky stories and traditions from many cultures, and even the lighting industry's little corner of the climate change problem, which we could effectively tackle RIGHT NOW, if there was only the willpower to do so. Aparna and John haven't lost hope. Aparna Venkatesan is an astronomer in the Department of Physics and Astronomy, and co-Director of the Tracy Seeley Center for Teaching Excellence, at the University of San Francisco. She works on studies of the first stars and quasars in the universe, and is also actively involved in projects in cultural astronomy and space policy. She currently serves as co-Chair of the American Astronomical Society's Committee to Protect Astronomy and the Space Environment (COMPASSE). Professor Venkatesan has been recognized internationally for her research and DEI leadership, featured widely in the media, and received numerous prizes and awards. She is deeply committed to increasing the retention of underrepresented groups in astronomy and STEM, and is active in developing scientific partnerships with Indigenous communities worldwide. Connect with Aparna: https://www.usfca.edu/faculty/aparna-venkatesan John Barentine is the Principal Consultant at Dark Sky Consulting, LLC, and was formerly the Director of Public Policy for the International Dark-Sky Association. He earned a Ph.D. in astronomy from the University of Texas at Austin, and previously held staff positions at the National Solar Observatory, Apache Point Observatory, and the Sloan Digital Sky Survey. Throughout his career, he has been involved in education and outreach efforts to help increase the public understanding of science. He is a member of the American Astronomical Society and the International Astronomical Union, and is a Fellow of the Royal Astronomical Society. The asteroid (14505) Barentine is named in his honor. His interests outside of astronomy and light pollution research include history, art and architecture, politics, law and current events. 

Merger Signatures are Common, but not Universal, In Massive, Recently-Quenched Galaxies at z~0 7 by Margaret Verrico et al. on Wednesday 30 November We present visual classifications of merger-induced tidal disturbances in 143 $rm{M}_* sim 10^{11}rm{M}_odot$ post-starburst galaxies at z$sim$0.7 identified in the SQuIGG$vec{L}$E Sample. This sample spectroscopically selects galaxies from the Sloan Digital Sky Survey that have stopped their primary epoch of star formation within the past $sim$500 Myrs. Visual classifications are performed on Hyper Suprime Cam (HSC) i-band imaging. We compare to a control sample of mass- and redshift-matched star-forming and quiescent galaxies from the Large Early Galaxy Census and find that post-starburst galaxies are more likely to be classified as disturbed than either category. This corresponds to a factor of $3.6^{+2.9}_{-1.3}$ times the disturbance rate of older quiescent galaxies and $2.1^{+1.9}_{-.73}$ times the disturbance rate of star-forming galaxies. Assuming tidal features persist for $lesssim500$ Myr, this suggests merging is coincident with quenching in a significant fraction of these post-starbursts. Galaxies with tidal disturbances are younger on average than undisturbed post-starburst galaxies in our sample, suggesting tidal features from a major merger may have faded over time. This may be exacerbated by the fact that, on average, the undisturbed subset is fainter, rendering low surface brightness tidal features harder to identify. However, the presence of ten young ($lesssim150$ Myr since quenching) undisturbed galaxies suggests that major mergers are not the only fast physical mechanism that shut down the primary epoch of star formation in massive galaxies at intermediate redshift. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16532v1

Merger Signatures are Common, but not Universal, In Massive, Recently-Quenched Galaxies at z~0 7 by Margaret Verrico et al. on Wednesday 30 November We present visual classifications of merger-induced tidal disturbances in 143 $rm{M}_* sim 10^{11}rm{M}_odot$ post-starburst galaxies at z$sim$0.7 identified in the SQuIGG$vec{L}$E Sample. This sample spectroscopically selects galaxies from the Sloan Digital Sky Survey that have stopped their primary epoch of star formation within the past $sim$500 Myrs. Visual classifications are performed on Hyper Suprime Cam (HSC) i-band imaging. We compare to a control sample of mass- and redshift-matched star-forming and quiescent galaxies from the Large Early Galaxy Census and find that post-starburst galaxies are more likely to be classified as disturbed than either category. This corresponds to a factor of $3.6^{+2.9}_{-1.3}$ times the disturbance rate of older quiescent galaxies and $2.1^{+1.9}_{-.73}$ times the disturbance rate of star-forming galaxies. Assuming tidal features persist for $lesssim500$ Myr, this suggests merging is coincident with quenching in a significant fraction of these post-starbursts. Galaxies with tidal disturbances are younger on average than undisturbed post-starburst galaxies in our sample, suggesting tidal features from a major merger may have faded over time. This may be exacerbated by the fact that, on average, the undisturbed subset is fainter, rendering low surface brightness tidal features harder to identify. However, the presence of ten young ($lesssim150$ Myr since quenching) undisturbed galaxies suggests that major mergers are not the only fast physical mechanism that shut down the primary epoch of star formation in massive galaxies at intermediate redshift. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16532v1

The dark side of galaxy stellar populations II: The dependence of star formation histories on halo mass and on the scatter of the main sequence by Laura Scholz-Diaz et al. on Wednesday 23 November Nearby galaxies are the end result of their cosmological evolution, which is predicted to be influenced by the growth of their host dark matter halos. This co-evolution potentially leaves signatures in present-day observed galaxy properties, which might be essential to further understand how the growth and properties of galaxies are connected to those of their host halos. In this work, we study the evolutionary histories of nearby galaxies both in terms of their host halos and the scatter of the star-forming main sequence by investigating their time-resolved stellar populations using absorption optical spectra drawn from the Sloan Digital Sky Survey. We find that galaxy star formation histories depend on the masses of their host halos, and hence they shape the evolution of the star-forming main sequence over cosmic time. Additionally, we also find that the scatter around the z=0 star-forming main sequence is not (entirely) stochastic, as galaxies with currently different star formation rates have experienced, on average, different star formation histories. Our findings suggest that dark matter halos might play a key role in modulating the evolution of star formation in galaxies, and thus of the main sequence, and further demonstrate that galaxies at different evolutionary stages contribute to the observed scatter of this relation. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.11779v1

Reconstructing and Classifying SDSS DR16 Galaxy Spectra with Machine-Learning and Dimensionality Reduction Algorithms by Felix Pat et al. on Wednesday 23 November Optical spectra of galaxies and quasars from large cosmological surveys are used to measure redshifts and infer distances. They are also rich with information on the intrinsic properties of these astronomical objects. However, their physical interpretation can be challenging due to the substantial number of degrees of freedom, various sources of noise, and degeneracies between physical parameters that cause similar spectral characteristics. To gain deeper insights into these degeneracies, we apply two unsupervised machine learning frameworks to a sample from the Sloan Digital Sky Survey data release 16 (SDSS DR16). The first framework is a Probabilistic Auto-Encoder (PAE), a two-stage deep learning framework consisting of a data compression stage from 1000 elements to 10 parameters and a density estimation stage. The second framework is a Uniform Manifold Approximation and Projection (UMAP), which we apply to both the uncompressed and compressed data. Exploring across regions on the compressed data UMAP, we construct sequences of stacked spectra which show a gradual transition from star-forming galaxies with narrow emission lines and blue spectra to passive galaxies with absorption lines and red spectra. Focusing on galaxies with broad emission lines produced by quasars, we find a sequence with varying levels of obscuration caused by cosmic dust. The experiments we present here inform future applications of neural networks and dimensionality reduction algorithms for large astronomical spectroscopic surveys. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.11783v1

Reconstructing and Classifying SDSS DR16 Galaxy Spectra with Machine-Learning and Dimensionality Reduction Algorithms by Felix Pat et al. on Tuesday 22 November Optical spectra of galaxies and quasars from large cosmological surveys are used to measure redshifts and infer distances. They are also rich with information on the intrinsic properties of these astronomical objects. However, their physical interpretation can be challenging due to the substantial number of degrees of freedom, various sources of noise, and degeneracies between physical parameters that cause similar spectral characteristics. To gain deeper insights into these degeneracies, we apply two unsupervised machine learning frameworks to a sample from the Sloan Digital Sky Survey data release 16 (SDSS DR16). The first framework is a Probabilistic Auto-Encoder (PAE), a two-stage deep learning framework consisting of a data compression stage from 1000 elements to 10 parameters and a density estimation stage. The second framework is a Uniform Manifold Approximation and Projection (UMAP), which we apply to both the uncompressed and compressed data. Exploring across regions on the compressed data UMAP, we construct sequences of stacked spectra which show a gradual transition from star-forming galaxies with narrow emission lines and blue spectra to passive galaxies with absorption lines and red spectra. Focusing on galaxies with broad emission lines produced by quasars, we find a sequence with varying levels of obscuration caused by cosmic dust. The experiments we present here inform future applications of neural networks and dimensionality reduction algorithms for large astronomical spectroscopic surveys. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.11783v1

The dark side of galaxy stellar populations II: The dependence of star formation histories on halo mass and on the scatter of the main sequence by Laura Scholz-Diaz et al. on Tuesday 22 November Nearby galaxies are the end result of their cosmological evolution, which is predicted to be influenced by the growth of their host dark matter halos. This co-evolution potentially leaves signatures in present-day observed galaxy properties, which might be essential to further understand how the growth and properties of galaxies are connected to those of their host halos. In this work, we study the evolutionary histories of nearby galaxies both in terms of their host halos and the scatter of the star-forming main sequence by investigating their time-resolved stellar populations using absorption optical spectra drawn from the Sloan Digital Sky Survey. We find that galaxy star formation histories depend on the masses of their host halos, and hence they shape the evolution of the star-forming main sequence over cosmic time. Additionally, we also find that the scatter around the z=0 star-forming main sequence is not (entirely) stochastic, as galaxies with currently different star formation rates have experienced, on average, different star formation histories. Our findings suggest that dark matter halos might play a key role in modulating the evolution of star formation in galaxies, and thus of the main sequence, and further demonstrate that galaxies at different evolutionary stages contribute to the observed scatter of this relation. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.11779v1

The SDSS-Gaia View of the Color-Magnitude Relation for Blue Horizontal-Branch Stars by Fabrícia O. Barbosa et al. on Monday 10 October We present an updated sample of blue horizontal-branch (BHB) stars selected from the photometric and spectroscopic data from Sloan Digital Sky Survey and its associated project Sloan Extension for Galactic Understanding and Exploration (SEGUE). With this data, we selected candidates for A-type stars in the color-color space and then a mixture modeling technique was implemented in order to distinguish between BHB and main-sequence/blue-straggler stars based on their surface gravity values ($log rm{g}$) estimated by the SEGUE Stellar Parameter Pipeline. Our robust approach allows us to attribute individual probabilities of each star truly being in the BHB stage. Hence, our method is advantageous in comparison to previous SEGUE BHB selections that adopted simple $log rm{g}$ cuts. We also revisit the color-magnitude relation for these stars and propose two calibrations, based on updated distances for Galactic globular clusters, to estimate absolute magnitudes with $(g-r)_0$ and $(u-r)_0$ colors. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.02820v2

Searching for velocity-dependent dark matter annihilation signals from extragalactic halos by Eric J. Baxter et al. on Sunday 18 September We consider gamma-ray signals of dark matter annihilation in extragalactic halos in the case where dark matter annihilates from a $p$-wave or $d$-wave state. In these scenarios, signals from extragalactic halos are enhanced relative to other targets, such as the Galactic Center or dwarf spheroidal galaxies, because the typical relative speed of the dark matter is larger in extragalactic halos. We perform a mock data analysis of gamma rays produced by dark matter annihilation in halos detected by the Sloan Digital Sky Survey. We include a model for uncorrelated galactic and extragalactic gamma ray backgrounds, as well as a simple model for backgrounds due to astrophysical processes in the extragalactic halos detected by the survey. We find that, for models which are still allowed by other gamma ray searches, searches of extragalactic halos with the current Fermi exposure can produce evidence for dark matter annihilation, though it is difficult to distinguish the $p$-wave and $d$-wave scenarios. With a factor $10times$ larger exposure, though, discrimination of the velocity-dependence is possible. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2205.02386v2

A Catalog of Quasar Properties from Sloan Digital Sky Survey Data Release 16 by Qiaoya Wu et al. on Sunday 11 September We present a catalog of continuum and emission line properties for 750,414 broad-line quasars included in the Sloan Digital Sky Survey Data Release 16 quasar catalog (DR16Q), measured from optical spectroscopy. These quasars cover broad ranges in redshift ($0.1lesssim zlesssim 6$) and luminosity ($44lesssim log (L_{rm bol}/{rm erg,s^{-1}})lesssim 48$), and probe lower luminosities than an earlier compilation of SDSS DR7 quasars. Derived physical quantities such as single-epoch virial black hole masses and bolometric luminosities are also included in this catalog. We present improved systemic redshifts and realistic redshift uncertainties for DR16Q quasars using the measured line peaks and correcting for velocity shifts of various lines with respect to the systemic velocity. About 1%, 1.4%, and 11% of the original DR16Q redshifts deviate from the systemic redshifts by $|Delta V|>1500,{rm km,s^{-1}}$, $|Delta V|in [1000,1500],{rm km,s^{-1}}$, and $|Delta V|in [500,1000],{rm km,s^{-1}}$, respectively; about $1900$ DR16Q redshifts were catastrophically wrong ($|Delta V|>10,000,{rm km,s^{-1}}$). We demonstrate the utility of this data product in quantifying the spectral diversity and correlations among physical properties of quasars with large statistical samples. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.03987v1

The number of possible places in a galaxy for life as we know it to develop depends on the number of stars which have planets, the presence of necessary elements such as iron, oxygen, nitrogen, and carbon, and the freedom from nearby supernova which could sterilize an otherwise habitable planet. The good news, the Sloan Digital Sky Survey in New Mexico has reported the discovery more than 150,000 galaxies which are rich with the three life enabling properties. The bad news is we will get monologues and not dialogs since it will take 9 million years for radio waves from the closest one to reach us and another 9 million years for our answer to make the trip back.

John Barentine is the founder of Dark Sky Consulting. He joins me in this episode to talk about returning the darkness to the night sky. John holds a Ph.D. in astronomy and has worked for the National Solar Observatory, Apache Point Observatory, and the Sloan Digital Sky Survey. He formerly worked as the Director of Public Policy for the International Dark Sky Association. He even has an asteroid named in his honor, known as (14505) Barentine! Check out the link for his three books below. Visit NightSkyTourist.com/28 for more information about this episode. LINKS IN THIS EPISODE Dark Sky Consulting: https://www.darkskyconsulting.com Books by John Barentine: https://www.johncbarentine.com/books.html International Dark Sky Association: https://www.darksky.org “Saving the Dark” documentary: http://savingthedark.com SPREAD THE WORD Help us reach more people by subscribing to the podcast, leaving a review, and sharing it with others. GET TO KNOW US MORE Visit NightSkyTourist.com to read our great blog articles, check out our resource page, and sign up for our newsletters. Our monthly newsletter has content that is exclusive for subscribers. SHARE YOUR QUESTION We want to hear your questions. They could even become part of a future Q&A. Record your question in a voice memo on your smartphone and email it to us at Hello@NightSkyTourist.com. COMMENTS OR QUESTIONS Email us at Hello@NightSkyTourist.com.

In this special “Meet the Expert” episode, two distinguished guests from Johns Hopkins University discuss their pioneering approach of applying methodologies, initially developed for astronomy, to the assessment of biomarkers of tumor microenvironment (TME). The guests are Dr. Janis Taube, director of Dermatopathology at Hopkins, and a co-Director of the TME Core at the Bloomberg-Kimmel Institute of Immunotherapy, and Dr. Alex Szalay, Bloomberg Distinguished Professor of Astronomy and Computer Science at Hopkins and the architect for the Science Archive of the Sloan Digital Sky Survey. The fascinating discussion focuses on an innovative multiplex imaging platform that they co-developed (AstroPath) for multidimensional assessment of spatially resolved interactions at the single-cell level of lung cancer and melanoma. See acast.com/privacy for privacy and opt-out information.

The mysteries of outer space have long fascinated scientists and academics, but an innovative research project has put ordinary people at the helm of exploring our cosmos. To celebrate World Space Week, Professor Bob Nicol and Professor Daniel Thomas join the Life Solved podcast to talk about Galaxy Zoo, a citizen-science project part-funded by the University of Portsmouth. Across a decade, 73,000 enthusiasts joined forces to classify galaxies in their spare time, leading to blossoming communities as well as advances in our understanding of the formation and interrelation of galaxies. What's more, these findings have led to breakthroughs in machine learning and the development of artificial intelligence, and inspired Zooniverse: the world's largest portal for people-powered research. FIND OUT MORE You can find out more about this work and other research at the University of Portsmouth website: https://www.port.ac.uk/research/research-projects You can find out more about Galaxy Zoo here on the Zooniverse portal:https://www.zooniverse.org/projects/zookeeper/galaxy-zoo/ Zooniverse is an incredible portal where 2.3 million people are taking part in research: https://www.zooniverse.org/projects Explore data from the Sloan Digital Sky Survey here: https://www.sdss.org Find out more about Professors Daniel Thomas and Bob Nichol here: https://researchportal.port.ac.uk/en/persons/daniel-thomas(f3c7db43-37c4-4f84-b9d4-f982a50ef9ad).html https://www.port.ac.uk/about-us/structure-and-governance/our-people/our-staff/bob-nichol https://twitter.com/robertcnichol?lang=en See acast.com/privacy for privacy and opt-out information.

There is no Nobel prize for astronomy, so the Kyoto Prize for Astronomy and Astrophysics may be the highest international recognition an astronomer can receive. Princeton University professor of astronomy Jim Gunn is the most recent recipient. Jim recently joined Mat Kaplan for a deep conversation about the wonder and beauty of deep space, about the Sloan Digital Sky Survey that Jim co-created and led, and much more. Is there an asteroid with Mat Kaplan’s name on it? That question is at the heart of the new space trivia contest from Bruce Betts.  Discover more at https://www.planetary.org/planetary-radio/james-gunn-sdss See omnystudio.com/listener for privacy information.

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

Alison Coil of UC San Diego's Center for Astrophysics and Space Sciences and Professor of Physics hosts a rare, candid conversation with James Gunn, considered the father of the unprecedented Sloan Digital Sky Survey, which to date has observed some 300 million objects, creating the most comprehensive 3D map of the universe. They discuss his experiences starting the SDSS and his future exploits in deep-sky observations. Includes his Kyoto Prize acceptance address delivered in Kyoto on the occasion of his being honored with the prestigious award. Series: "Kyoto Prize Symposium" [Science] [Show ID: 36809]

RumSnak ser denne gang nærmere på galakser - store samlinger af milliarder af stjerner, støv, gas og meget andet, ligesom vores egen Mælkevej. Man ved ikke nøjagtig hvor mange galakser der findes i Universet - men man skyder på flere hundrede milliarder galakser, som altså hver især har milliarder af stjerner. Samlinger af galakser, det man kalder galaksehobe, er de største strukturer man kender til i universet. Men vi skal også snævre fokus bare en lille smule ind, og se nærmere på galaksernes centre. Vi har talt med Mikkel Theiss Kristensen, der for tiden holder til på Hull University i England, og som forsker i galakser, nærmere bestemt det man kalder aktive galaksekerner. Der bliver dog også tid til en håndfuld korte nyheder - denne gang blandt andet om Europa-billeder, satellit-solskærme og NASA-affyringer. LINKS NYHEDER Genbehandlede fotos af Jupiters måne Europa (https://www.space.com/jupiter-moon-europa-chaos-terrain-detailed-photos.html) NASA planlægger affyring den 27. maj med SpaceX-grej (https://www.spacedaily.com/reports/NASA_SpaceX_target_historic_spaceflight_despite_pandemic_999.html) Stjerner danser om sorte huller (https://www.eso.org/public/news/eso2006/) NASA giver 1 milliard dollars til udvikling af nye Månelandere (https://www.theverge.com/2020/4/30/21242837/nasa-spacex-blue-origin-dynetics-human-lunar-landers) SpaceX’s Starlink-satellitter skal have solskærme (https://www.spacedaily.com/reports/SpaceX_develops_new_sunshade_to_make_Starlink_satellites_less_visible_from_Earth_999.html) GALAKSER Mikkel Theiss Kristensen (https://www.linkedin.com/in/mikkel-kristensen-479256132/) Den Store Danske med fin artikel om galakser (http://denstoredanske.dk/It,_teknik_og_naturvidenskab/Astronomi/Galakser/galakse) Hubble Deep Field - vilde billeder af Universets mange galakser (https://en.wikipedia.org/wiki/Hubble_Deep_Field) Om de aktive galaksekerner (https://en.wikipedia.org/wiki/Active_galactic_nucleus) Mikkel får bla. data fra Sloan Digital Sky Survey, når han ikke observerer selv (https://en.wikipedia.org/wiki/Sloan_Digital_Sky_Survey)

The National Science Foundation has merged all of its ground based astronomy facilities as of October 1, 2019.  These facilities include Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, the Gemini Observatory, the Community Science Data Center and the Large Synoptic Survey Telescope. In this podcast, NSF’s OIR Lab Deputy Director Dr. Beth Willman discusses the launch of the new organization. Dr. Beth Willman is Deputy Director of NSF’s National Optical-Infrared Astronomy Research Laboratory. https://nationalastro.org/ @NatOIRLab BIO: Rob Sparks is a Science Education Specialist at the National Optical Astronomy Observatory. A lifelong astronomy enthusiast, he earned a B.A. in physics at Grinnell College and his M.S. at Michigan State University. He taught high school physics, math and astronomy for 11 years at schools on St. Croix, Florida and Wisconsin. He spent the 2001-2002 school year working on the Sloan Digital Sky Survey as a recipient of the Fermilab Teacher Fellowship. He spent the summer of 2003 at the National Radio Astronomy Observatory as part of the Research Experience for Teachers. He has been working as a NASA Astrophysics Ambassador since 2002.    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.

Father Lawrence Machia, OSB, is a Benedictine monk at St. Vincent College and Archabbey in Latrobe, PA. The public can view his 2019 Society of Catholic Scientists presentation on You Tube. Father Machia’s talk made reference to Galileo’s letter to Benedetto Castelli. Dr. Daniel Vanden Berk is an associate professor of physics at St. Vincent College. Fr. Machia and Dr. Vanden Berk, both very interested in astronomy, have worked together on designing planetarium shows on the St. Vincent campus. They have always seen the complementarity of science and religion, faith and reason, in contrast to many people’s rejection of religion based on supposed conflicts with scientific, rational, experiential learning. Dr. Vanden Berk was intrigued at an early age by the “Cosmos”- series presented on PBS by Carl Sagan, but the program posited a conflict between science and faith. Among Dr. Vanden Berk’s astronomical adventures: working on the Sloan Digital Sky Survey. He has worked with the Fermi National Accelerator Laboratory, processing data captured by the Digital Sky Survey. Episode timeline: 3:00 Machia's time in college, science to theology 5:00 Machia's beginning to discern a religious vocation 8:00 St. Vincent College and the archabbey 10:00 Pre-novitiate and novitiate 12:00 Vows 15:00 Why TSSM, following on from Lawrence's plans to finish and continue his physics education 16:00 Begin vanden Berk 18:00 Sci-fi influences 20:00 He and his wife's discernment process 22:00 Daniel's early career, the early Hubble mission 24:00 Sky surveys 26:00 Texas sky survey

Humans have been studying the stars for thousands of years, but astrophysicist Juna Kollmeier is on a special mission: creating the most detailed 3-D maps of the universe ever made. Journey across the cosmos as she shares her team's work on the Sloan Digital Sky Survey, imaging millions of stars, black holes and galaxies in unprecedented detail. If we maintain our pace, she says, we can map every large galaxy in the observable universe by 2060. "We've gone from arranging clamshells to general relativity in a few thousand years," she says. "If we hang on 40 more, we can map all the galaxies." Hosted on Acast. See acast.com/privacy for more information.

Люди изучали звёзды в течение тысячелетий, но астрофизик Джуна Коллмайер выполняет специальную миссию: она создаёт самые подробные трёхмерные карты Вселенной. Она приглашает нас в космическое путешествие и рассказывает о работе своей команды в Sloan Digital Sky Survey, показывая миллионы звёзд, чёрных дыр и галактик в беспрецедентных подробностях. По её словам, если учёные продолжат свою работу, то к 2060 году смогут создать карту каждой большой галактики в наблюдаемой Вселенной. «Мы перешли от моллюсков к общей теории относительности за несколько тысяч лет, — говорит она. — Если мы продержимся ещё сорок, мы сможем нанести на карту все галактики».

Los humanos han estado estudiando las estrellas durante miles de años, pero la astrofísica Juna Kollmeier tiene una misión especial: crear los mapas en 3D más detallados del universo. Viaja a través del cosmos mientras comparte el trabajo de su equipo en Sloan Digital Sky Survey, con imágenes de millones de estrellas, agujeros negros y galaxias con detalles sin precedentes. Si mantenemos nuestro ritmo, dice, podemos mapear cada gran galaxia en el universo observable para el año 2060. "Hemos pasado de organizar las conchas a la relatividad general en unos pocos miles de años", dice ella. "Si nos aferramos a 40 más, podemos mapear todas las galaxias".

Os seres humanos estudam as estrelas há milhares de anos, mas a astrofísica Juna Kollmeier está em uma missão especial: criar os mapas 3D mais detalhados do Universo já feitos. Viaje pelo cosmos enquanto ela compartilha o trabalho da equipe dela no Sloan Digital Sky Survey, formando imagens de milhões de estrelas, buracos negros e galáxias em detalhes sem precedentes. Se mantivermos o ritmo, diz ela, poderemos mapear todas as grandes galáxias do Universo observável até 2060. "Passamos da organização de conchas para a relatividade geral em alguns milhares de anos", diz ela. "Se esperarmos mais 40, poderemos mapear todas as galáxias."

Humans have been studying the stars for thousands of years, but astrophysicist Juna Kollmeier is on a special mission: creating the most detailed 3-D maps of the universe ever made. Journey across the cosmos as she shares her team's work on the Sloan Digital Sky Survey, imaging millions of stars, black holes and galaxies in unprecedented detail. If we maintain our pace, she says, we can map every large galaxy in the observable universe by 2060. "We've gone from arranging clamshells to general relativity in a few thousand years," she says. "If we hang on 40 more, we can map all the galaxies."

In this podcast extra episode, released during Pride month, we return to this April’s European Week of Astronomy and Space Science where we spoke to Dr Ashley Spindler to find out more about: Galaxy evolution, the evolution of galaxy structures and star formation from the MaNGA project using Sloan Digital Sky Survey data South East Physics Network placement opportunities for post graduate students The challenges and obstacles that still exist for the LGBT community in the workplace and education efforts to make science environments more open and welcoming to all people. Ashley can also be found at @Ashley_Nova_ on Twitter.

Stream Episodes on demand from www.bitesz.com or www.spacetimewithstuartgary.com (both mobile friendly) * Magnetic bridge linking galaxies Astronomers have detected a magnetic field associated with the Magellanic Bridge, the filament of gas stretching 75,000 light-years between the Milky Way Galaxy’s nearest galactic neighbours -- the Large and Small Magellanic Clouds. The findings provide the first ever detection of a magnetic field in the bridge and may provide clues to how it’s formed. *New clues about the origins of brown dwarfs Astronomers have discovered a spectacular extended jet blasting almost a lightyear out from a young brown dwarf. The discovery provides new insights into the origins of brown dwarfs, supporting the emerging picture that these sub stellar objects form in the same way stars do. *Astronomers produce the largest map of the Universe ever made Astronomers with the Sloan Digital Sky Survey have created the first map of the large-scale structure of the universe based entirely on the positions of quasars. The new findings are consistent with Albert Einstein’s theory of general relativity. *India launches locally built satellite India has launched a new locally built telecommunications satellite. The successful flight shows India’s growing space capabilities -- both building and launching its own spacecraft.  If you're enjoying SpaceTime, please help out by sharing and telling your friends. The best recommendation I can get is one from you. Thank you... #astronomy #space #science #technology #news #astrophysics #NASA Learn more about your ad choices. Visit megaphone.fm/adchoices Support this show http://supporter.acast.com/spacetime. See acast.com/privacy for privacy and opt-out information.

Astrophiz 27 out now on iTunes and Soundcloud. Our first feature interview after our fabulous summer break is with Dr Amanda Bauer, who has just been appointed as the new Head of Education and Public Outreach at the Large Synoptic Survey Telescope which is high up in the mountains in Chile in South America. Amanda has worked at the Max Planck Institute and on the famous Sloan Digital Sky Survey and she now specialises in Galactic Evolution and Astronomical Outreach. Dr Ian Musgrave in our regular feature, ‘What’s up Doc?’ tells us what to look for in the night sky this week using naked eye, binoculars or telescopes. Comet 45P and Vesta observations. In the news: Our Milky Way is being pushed and pulled around every which way, Orphan Black Holes and a ‘Red Nova’ predicted for 2022.

Wed, 16 Dec 2015 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/19038/ https://edoc.ub.uni-muenchen.de/19038/1/Huber_Markus_B.pdf Huber, Markus B. dd

Sam Harris speaks with MIT cosmologist Max Tegmark about the foundations of science, our current understanding of the universe, the risks of future breakthroughs in artificial intelligence, and other topics. Max Tegmark is a professor of physics who has published more than two hundred technical papers and been featured in dozens of science documentaries. His work with the Sloan Digital Sky Survey on galaxy clustering shared the first prize in Science magazine’s “Breakthrough of the Year: 2003.” He is the author of Our Mathematical Universe. For more information about his work, please visit his MIT website and the Future of Life Institute. Episodes that have been re-released as part of the Best of Making Sense series may have been edited for relevance since their original airing.

In this dissertation, we consider the origin of thermonuclear supernovae, known by their observational classification as type Ia (hereafter SNe Ia). In particular, we develop an entirely new means to test the ``single-degenerate'' hypothesis, in which the progenitors of these tremendous explosions are suggested to be hot and luminous accreting white dwarfs. We then strongly constrain the role of any such ``hot-mode'' SN Ia progenitor channel using both a population-based argument and an individual case study, before concluding with some more general considerations of nebulae ionized by accreting white dwarfs. Type Ia supernovae have now been the subject of intensive study for decades, particularly in light of their role as standard(-izable) candles in measuring cosmological distances. However, there remains no consensus model for the evolutionary channel(s) by which they originate. In the so-called ``double-degenerate'' scenario, a binary pair of white dwarfs shed angular momentum through gravitational-wave radiation, until they inspiral and merge, triggering an explosion. Alternatively, in the classic picture of the single-degenerate scenario, a white dwarf accretes hydrogen-rich material from some main sequence or red giant companion, and grows through nuclear burning of this material at its surface until reaching sufficient mass to trigger an explosion. This suggests that single-degenerate progenitors should be extremely luminous sources in the EUV and soft X-ray bands during the accretion phase (lasting $sim 10^{5}$--$10^{6}$ years). For this reason, such objects are generally associated with observed ``supersoft X-ray sources'' (SSSs). Previous efforts to detect or constrain the role of any such channel have focused on detecting these objects directly in the soft X-ray band (photon energies in the range 0.3 -- 0.7 keV), either on an individual basis or as the combined emission of a diffuse population. Such an approach has yielded important constraints, but only if white dwarfs accrete principally at very high temperatures (T $sim$ $5times 10^{5}$K). However, observed SSSs are understood to lie in a broad range of temperatures, with a possible range of at least $2 times 10^{5}$--$10^{6}$K, and some theoretical models suggest even lower temperatures are possible. This necessitates the development of an alternative, complimentary test which can constrain the luminosity of accreting white dwarfs across a wider range of photospheric temperatures. In this work, we demonstrate that if the single-degenerate model is correct, then accreting, nuclear-burning white dwarfs should provide the dominant source of ionizing radiation in passively-evolving galaxies, roughly 40% of which are known to host extended low-ionization emission-line regions (so-called ``retired'' galaxies, i.e. emission-line galaxies without either a central AGN or significant ongoing star formation). Therefore, one can search for the presence of any high-temperature single-degenerate progenitor population in these galaxies by looking for emission lines characteristic of ionization by very high-temperature ($10^{5}$ K -- $10^{6}$ K) sources. In particular, we find that recombination lines of He II, and forbidden lines of [N I] and [O I], provide the most sensitive diagnostics in retired galaxies to assess the role of accreting white dwarfs as SN Ia progenitors in any ``{bf hot}-mode'' (T $gtrsim 1.2times 10^{5}$K) accretion regime. Following this, we limit the contribution of any high-temperature single-degenerate channel to the SN Ia rate at relatively early delay-times (1 Gyr $leq$ t $leq$ 4 Gyr) to $

The determination of photometric redshifts is essential for many subjects in cosmology and extragalactic astronomy, like the large scale structure of the Universe, gravitational lensing, or galaxy evolution. If the spectral energy distribution (SED) of a galaxy is measured with high enough spectral resolution, the redshift can be easily derived through the absorption and emission lines which are created by the elements in the galaxy. However, currently more telescopes are equipped with large cameras with charged coupled devices (CCDs) that observe the sky through optical filters. With these photometric observations it is possible to detect much fainter astronomical objects than with spectroscopy. Furthermore, photometric observations are less time consuming and cheaper in comparison, wherefore they are preferentially used for observations of statistical meaningful cosmological volumes. Nonetheless, photometric data, which are often gained by observations through broadband filters, are not as precisely resolved as spectra. Therefore one does not have information about the accurate position in wavelength of spectral lines, but only about the overall shape of the SED. This is the reason why so-called photometric redshifts have to be derived by statistical means. One approach to estimate the redshift through photometry alone are template fitting methods which compare the fluxes predicted by model spectra with the observations. After that, a likelihood analysis is performed with which a probability density function P(z) and the most probable value of z can be derived. To achieve high accuracies with photometric redshift template fitting techniques, the model spectra as well as their corresponding prior probabilities have to be chosen carefully. In this work I use photometric and spectroscopic data of luminous red galaxies from the Sloan Digital Sky Survey (SDSS). I analyze the precision of photometric redshifts estimated with model SEDs specifically designed to match the set of luminous red galaxies of SDSS-II at redshifts z ≤ 0.5 in color and I compare them with published results. These models were created without information on their properties at wavelengths shorter than the SDSS u band. However, the galaxy UV characteristics derived from the model SEDs match those of other observations. Furthermore, I investigate the SED properties derived from the best fitting models with respect to spectroscopic data as functions of redshift and luminosity. At lower redshifts less luminous galaxies from our sample on average show increased signs of star formation in comparison to galaxies with higher luminosities. This is supported by analyses of the line strengths in the spectra. Moreover, star formation activity increases with increasing redshift which is caused by the aging of the galaxy population from higher to lower redshifts. I also generate model spectra for red galaxies from the SDSS-III located at even higher redshifts 0.45 ≤ z ≤ 0.9. For this I modify the shape of theoretical spectra to match the data of the analyzed galaxies to a better extent. The multidimensional space defined by the colors and the absolute magnitude of the galaxies is reduced to two dimensions through a self-organizing map. The map is then partitioned by a k-means algorithm which identifies clusters in the data. From the cluster cells I select model spectra which represent the galaxies from within the same cell. A selection of the models is then used as a template set for photometric redshift estimation. I find that our models improve the redshift accuracy in comparison to the results published by SDSS.

Paul Crowther provides an overview of the different types of galaxy, plus galaxy clusters and the three dimensional structure of the local Universe , enhanced by stunning images from NASA spacecraft, and the Sloan Digital Sky Survey

Galaxy Zoo is a Citizen Science project, part of the Zooniverse, which asks the public to classify the morphology of galaxies using images taken by Hubble and the Sloan Digital Sky Survey.

Galaxy Zoo is a Citizen Science project, part of the Zooniverse, which asks the public to classify the morphology of galaxies using images taken by Hubble and the Sloan Digital Sky Survey.

The introduction of a so-called dark sector in cosmology resolved many inconsistencies between cosmological theory and observation, but it also triggered many new questions. Dark Matter (DM) explained gravitational effects beyond what is accounted for by observed luminous matter and Dark Energy (DE) accounted for the observed accelerated expansion of the universe. The most sought after discoveries in the field would give insight into the nature of these dark components. Dark Matter is considered to be the better established of the two, but the understanding of its nature may still lay far in the future. This thesis is concerned with explaining and eliminating the discrepancies between the current theoretical model, the standard model of cosmology, containing the cosmological constant Λ as the driver of accelerated expansion and Cold Dark Matter (CDM) as main source of gravitational effects, and available observational evidence pertaining to the dark sector. In particular, we focus on the small, galaxy-sized scales and below, where N-body simulations of cosmological structure in the ΛCDM universe predict much more structure and therefore much more power in the matter power spectrum than what is found by a range of different observations. This discrepancy in small scale power manifests itself for example through the well known "dwarf-galaxy problem'" (e.g. Klypin, 1999), the density profiles and concentrations of individual haloes (Donato, 2009) as well as the properties of voids (Tikhonov, 2009). A physical process that would suppress the fluctuations in the dark matter density field might be able to account for these discrepancies. Free-streaming dark matter particles dampen the overdensities on small scales of the initial linear matter density field. This corresponds to a suppression of power in the linear matter power spectrum and can be modeled relatively straightforwardly for an early decoupled thermal relic dark matter particle. Such a particle would be neutrino-like, but heavier; an example being the gravitino in the scenario, where it is the Lightest Supersymmetric Particle and it decouples much before neutrinos, but while still relativistic. Such a particle is not classified as Hot Dark Matter, like neutrinos, because it only affects small scales as opposed to causing a suppression at all scales. However, its free-streaming prevents the smallest structures from gravitationally collapsing and does therefore not correspond to Cold Dark Matter. The effect of this Warm Dark Matter (WDM) may be observable in the statistical properties of cosmological Large Scale Structure. The suppression of the linear matter density field at high redshifts in the WDM scenario can be calculated by solving the Boltzmann equations. A fit to the resulting linear matter power spectrum, which describes the statistical properties of this density field in the simple thermal relic scenario is provided by Viel (2004). This linear matter power spectrum must then be corrected for late-time non-linear collapse. This is rather difficult already in the standard cosmological scenario, because exact solutions the the evolution of the perturbed density field in the nonlinear regime cannot be found. The widely used approaches are to the 'halofit' method of Smith (2002), which is essentially a physically motivated fit to the results of numerical simulations or using the even more physical, but slightly less accurate halo model. However, both of these non-linear methods were developed assuming only CDM and are therefore not necessarily appropriate for the WDM case. In this thesis, we modify the halo model (see also Smith, 2011) in order to better accommodate the effects of the smoothed WDM density field. Firstly, we treat the dark matter density field as made up of two components: a smooth, linear component and a non-linear component, both with power at all scales. Secondly, we introduce a cut-off mass scale, below which no haloes are found. Thirdly, we suppress the mass function also above the cut-off scale and finally, we suppress the centres of halo density profiles by convolving them with a Gaussian function, whose width depends on the WDM relic thermal velocity. The latter effect is shown to not be significant in the WDM scenario for the calculation of the non-linear matter power spectrum at the scales relevant to the present and near future capabilities of astronomical surveys in particular the Euclid weak lensing survey. In order to determine the validity of the different non-linear WDM models, we run cosmological simulations with WDM (see also Viel, 2012) using the cutting edge Lagrangian code Gadget-2 (Springel, 2005). We provide a fitting function that can be easily applied to approximate the non-linear WDM power spectrum at redshifts z = 0.5 - 3.0 at a range of scales relevant to the weak lensing power spectrum. We examine the simple thermal relic scenario for different WDM masses and check our results against resolution issues by varying the size and number of simulation particles. We finally briefly discuss the possibility that the effects of WDM on the matter power spectrum might resemble the analogous, but weaker and larger scale effects of the free-streaming of massive neutrinos. We consider this with the goal of re-examining the Sloan Digital Sky Survey data (as in Thomas, 2010). We find that the effects of the neutrinos might just differ enough from the effects of WDM to prevent the degeneracy of the relevant parameters, namely the sum of neutrino masses and the mass of the WDM particle.

Lawrence Berkeley National Laboratory physicist and dark energy hunter David Schlegel chats with Sabin Russell, former San Francisco Chronicle reporter turned Berkeley Lab science writer. David Schlegel is an astrophysicist at the Lawrence Berkeley National Laboratory and the principal investigator of Baryon Oscillation Spectroscopic Survey (BOSS), the largest of four night-sky surveys being conducted as part of the Sloan Digital Sky Survey (SDSS). Series: "Lawrence Berkeley National Laboratory " [Science] [Show ID: 22550]

Lawrence Berkeley National Laboratory physicist and dark energy hunter David Schlegel chats with Sabin Russell, former San Francisco Chronicle reporter turned Berkeley Lab science writer. David Schlegel is an astrophysicist at the Lawrence Berkeley National Laboratory and the principal investigator of Baryon Oscillation Spectroscopic Survey (BOSS), the largest of four night-sky surveys being conducted as part of the Sloan Digital Sky Survey (SDSS). Series: "Lawrence Berkeley National Laboratory " [Science] [Show ID: 22550]

Lawrence Berkeley National Laboratory physicist and dark energy hunter David Schlegel chats with Sabin Russell, former San Francisco Chronicle reporter turned Berkeley Lab science writer. David Schlegel is an astrophysicist at the Lawrence Berkeley National Laboratory and the principal investigator of Baryon Oscillation Spectroscopic Survey (BOSS), the largest of four night-sky surveys being conducted as part of the Sloan Digital Sky Survey (SDSS). Series: "Lawrence Berkeley National Laboratory " [Science] [Show ID: 22550]

Lawrence Berkeley National Laboratory physicist and dark energy hunter David Schlegel chats with Sabin Russell, former San Francisco Chronicle reporter turned Berkeley Lab science writer. David Schlegel is an astrophysicist at the Lawrence Berkeley National Laboratory and the principal investigator of Baryon Oscillation Spectroscopic Survey (BOSS), the largest of four night-sky surveys being conducted as part of the Sloan Digital Sky Survey (SDSS). Series: "Lawrence Berkeley National Laboratory " [Science] [Show ID: 22550]

The Sloan Digital Sky Survey Captures the UniverseLearn more about your ad choices. Visit megaphone.fm/adchoices

Chris Lintott of the University of Oxford discusses The Galaxy Zoo, an internet-based program for enlisting the help of amateur astronomers in cataloguing other galaxies.

Chris Lintott of the University of Oxford discusses The Galaxy Zoo, an internet-based program for enlisting the help of amateur astronomers in cataloguing other galaxies.

Chris Lintott of the University of Oxford discusses The Galaxy Zoo, an internet-based program for enlisting the help of amateur astronomers in cataloguing other galaxies.

Abstract: I present galaxy clustering results from the Sloan Digital Sky Survey that reveal the signature of acoustic oscillations of the photon-baryon fluid in the first million years of the Universe. The scale of this feature can be computed and hence the detection in the galaxy clustering serves as a standard ruler, giving a geometric distance to a redshift of 0.35. I will discuss the implications of this measurement for the composition of the universe, including dark energy and spatial curvature. I will close with a discussion of the prospects for future redshift surveys to use the acoustic peak to map the expansion history of the universe. February 1, 2007

The cosmic large scale structure is of special relevance for testing current cosmological theories about the origin and evolution of the Universe. Throughout cosmic history, it evolved from tiny quantum fluctuations, generated during the early epoch of inflation, to the filamentary cosmic web presently observed by our telescopes. Observations and analyses of this large scale structure will hence test this picture, and will provide valuable information on the processes of cosmic structure formation as well as they will reveal the cosmological parameters governing the dynamics of the Universe. Beside measurements of the cosmic microwave backround, galaxy observations are of particular interest to modern precision cosmology. They are complementary to many other sources of information, such as cosmic microwave background experiments, since they probe a different epoch. Galaxies report the cosmic evolution over an enormous period ranging from the end of the epoch of reionization, when luminous objects first appeared, till today. For this reason, galaxy surveys are excellent probes of the dynamics and evolution of the Universe. Especially the Sloan Digital Sky Survey is one of the most ambitious surveys in the history of astronomy. It provides measurements of 930,000 galaxy spectra as well as the according angular and redshift positions of galaxies over an area which covers more than a quarter of the sky. This enormous amount of precise data allows for an unprecedented access to the three dimensional cosmic matter distribution and its evolution. However, observables, such as positions and properties of galaxies, provide only an inaccurate picture of the cosmic large scale structure due to a variety of statistical and systematic observational uncertainties. In particular, the continuous cosmic density field is only traced by a set of discrete galaxies introducing statistical uncertainties in the form of Poisson distributed noise. Further, galaxy surveys are subject to a variety of complications such as instrumental limitations or the nature of the observation itself. The solution to the underlying problem of characterizing the large scale structure in the Universe therefore requires a statistical approach. The main theme of this PhD-thesis is the development of new Bayesian data analysis methods which provide a complete statistical characterization and a detailed cosmographic description of the large scale structure in our Universe. The required epistemological concepts, the mathematical framework of Bayesian statistics as well as numerical considerations are thoroughly discussed. On this basis two Bayesian data analysis computer algorithms are developed. The first of which is called ARES (Algorithm for REconstruction and Sampling). It aims at the joint inference of the three dimensional density field and its power-spectrum from galaxy observations. The ARES algorithm accurately treats many observational systematics and statistical uncertainties, such as the survey geometry, galaxy selection effects, blurring effects and noise. Further, ARES provides a full statistical characterization of the three dimensional density field, the power-spectrum and their joint uncertainties by exploring the high dimensional space of their joint posterior via a very efficient Gibbs sampling scheme. The posterior is the probability of the model given the observations and all other available informations. As a result, ARES provides a sampled representation of the joint posterior, which conclusively characterizes many of the statistical properties of the large scale structure. This probability distribution allows for a variety of scientific applications, such as reporting any desired statistical summary or testing of cosmological models via Bayesian model comparison or Bayesian odds factors. The second computer algorithm, HADES (Hamiltonian Density Estimation and Sampling), is specifically designed to infer the fully evolved cosmic density field deep into the non-linear regime. In particular, HADES accurately treats the non-linear relationship between the observed galaxy distribution and the underlying continuous density field by correctly accounting for the Poissonian nature of the observables. This allows for very precise recovery of the density field even in sparsely sampled regions. HADES also provides a complete statistical description of the non-linear cosmic density field in the form of a sampled representation of a cosmic density posterior. Beside the possibility of reporting any desired statistical summary of the density field or power-spectrum, such representations of the according posterior distributions also allow for simple non-linear and non-Gaussian error propagation to any quantity finally inferred from the analysis results. The application of HADES to the latest Sloan Digital Sky Survey data denotes the first fully Bayesian non-linear density inference conducted so far. The results obtained from this procedure represent the filamentary structure of our cosmic neighborhood in unprecedented accuracy.

Trencséni Márton: Sloan Digital Sky Survey

Our current understanding of structure formation in the Universe seems to be well described by a hierarchical scenario, in which small units assemble first to produce more massive systems. In recent years, much observational evidence has been accumulated, indicating that star formation proceeded instead in an antihierarchical fashion. Constraining the age and chemical composition of the stellar populations in galaxies should help shed light on this apparent dichotomy between mass assembly and star formation activity. The integrated spectra of galaxies contain valuable clues about the ages and metallicities of the stars producing the light. However, at first order, they are affected in a similar way by age and metallicity. Studies of more refined spectral diagnostics, such as individual stellar absorption features, are thus needed to provide more stringent constraints on these parameters. This method has been limited so far to small samples of elliptical galaxies, using population synthesis models with limited spectral resolution and restricted coverage in stellar effective temperatures. The objective of this thesis is the interpretation of the optical spectra of large samples of nearby galaxies in terms of the light-weighted metallicity, age and mass of their stellar populations. I have developed a new method to simultaneously derive median-likelihood estimates of each physical parameter and the associated confidence intervals. The method, based on a recent highresolution population synthesis code with full temperature coverage, consists in comparing each observed spectrum with a comprehensive library of star formation histories. The constraints are set by the simultaneous fit of an optimally selected set of spectral absorption features. I have applied this method to a sample of 200,000 galaxies from the Sloan Digital Sky Survey, including galaxies with any star formation history, from quiescent early-type to actively star forming galaxies. Thanks to the unprecedented statistics, I could give an accurate description of the galaxy distribution in the full physical parameters space. The relation between stellar metallicity, age and stellar mass shows a rapid transition from low-mass, young, metal-poor to high-mass, old, metal-rich galaxies at a stellar mass of 3×10^10 solar masses, the same characteristic scale of several observed bi-modalities in galaxy properties. The stellar metallicity-mass relation is interpreted as a manifestation of galactic winds, which are more efficient in removing metals from the shallow potential well of low-mass galaxies. I then explored the implications of the above relations to re-assess the physical origin of observed scaling relations of elliptical galaxies, linking their luminous and dynamical mass to the properties of their stellar populations. The relations are driven by an increase in metallicity, age and element abundance ratios with galaxy mass. The scatter is contributed by a similar amount by both age and metallicity. The increasing spread towards younger ages at low stellar masses indicates that low-mass ellipticals either formed their stars later or have a more extended star formation history. This hints at a shift in stellar growth towards less massive galaxies in recent epochs. The large ranges in observational and physical properties covered by SDSS galaxies make it a representative sample of the local Universe. I could thus derive the total mass density of metals and baryons locked up in stars today. I have also studied how metals and stellar mass are distributed as a function of various galaxy properties. The galaxies containing the bulk of the total stellar mass (massive, bulge-dominated galaxies with old stellar populations) are also those that contribute the largest fraction of metals, as expected from the mass-metallicity relation. These quantities set the fundamental constraints at the present epoch of the cosmic star formation and chemical enrichment histories. The more detailed knowledge of the relations between galaxy physical parameters allows a more direct comparison with predictions from semi-analytic models of galaxy formation and evolution. Moreover, the more robust constraints represent an important calibration at redshift zero for similar studies at higher redshifts.

Taking a census of all the luminous objects in one-quarter of the visible cosmos is a hefty accounting job. It takes a specially-built telescope on task every clear night for eight years, wielding one of the biggest digital cameras on the planet. Over a hundred million stars, galaxies, and quasars have been tallied so far. Meet the astronomical observers and theorists set on divining the three-dimensional structure and origins of the Universe from these unprecedented scores of data.

Die moderne Astrophysik steht vor der Herausforderung, neueste Beobachtungen mit den theoretischen und numerischen Modellen der Galaxienentstehung und -entwicklung zu konfrontieren. So hofft man, die wichtigsten physikalischen Prozesse und ihre Zeitskalen identifizieren zu koennen. In dieser Arbeit nehmen wir eine komplette, helligkeits--limitierte Auswahl von 1862 Galaxien aus der Sloan Digital Sky Survey (SDSS), um eine Anzahl von globalen und strukturellen Parametern zu untersuchen. Diese Auswahl beinhaltet helle Objekte mit einer r--Band Helligkeit von < 15.9 im nahen Universum mit einer Rotverschiebung von z < 0.12. Sie enthaelt elliptische, Spiral- und irregulaere Galaxien. Photometrische Daten sind fuer die u, g, r, i und z--Baender angegeben und von 1588 Galaxien wurden nachtraeglich Spektra genommen. Die `Bulge' Komponente der Galaxien wird mit Sersic und de Vaucouleurs Modellen modelliert, waehrend die Scheibenkomponente mit einer exponentiellen Verteilung modelliert wird. Die Messung des Lichtanteils in `Bulge' und Scheibenkomponente gibt Aufschluss ueber die Effizienz des hierarchischen Strukturbildungsprozesses. In Kapitel 3 zeigen wir, dass der mittlere Anteil des Lichts aus der Scheibe stark mit der totalen absoluten Helligkeit der Galaxie zunimmt. Unabhaengige r und i Band Analysen ergeben einen sehr aehnlichen Trend. Zum ersten Mal schaetzen wir den volumengemittelten Anteil des Lichts aus der Scheibenkomponente von Galaxien ab und stellen fest, dass ungefaehr (55 +- 2) % des gesamten Lichts im lokalen Universum aus Scheiben kommt. Wir ermitteln auch die Leuchtkraftfunktion fuer reine 'Bulges', also fuer Strukturen ohne Scheibenanteil, die nicht einfache Spheroide sind. In Kapitel 4 studieren wir die Abhaengigkeiten von visuellen und quantitativen morphologischen Klassifikationskriterien mit dem Ziel sauberere Galaxienkataloge zu erstellen, besonders bei hohen Rotverschiebungen, wo die Klassifikation schwierig ist. Wir finden, dass Galaxienfarben, effektive Oberflaechenhelligkeit, Masse/Licht Anteil, und Asymmetrie Parameter einen Mehrparameter Raum aufspannen, in der alle Galaxien je nach morphologischem Typ eindeutig positioniert sind. In Kapitel 5 beobachten wir einen klaren Trend, mit dem die Skalenlaenge der Scheiben mit ihrer Helligkeit zunimmt, und dieser Trend ist unabhaengig vom photometrischen Band und der morphologischen Klasse. Es existiert auch eine klare Abhaengigkeit zwischen dem effektiven Radius des `Bulge' und seiner Helligkeit, aber die Steigung dieser Relation aendert sich mit dem morphologischem Typ. Sie ist steiler fuer fruehere Typus, was uns zu der Schlussfolgerung fuehrt, dass die Skalenlaenge weniger von der Morphologie abhaengt als die Skalenlaenge des `Bulges'. Dies legt nahe, dass `Bulges' in fruehen und spaeteren Galaxien in unterschiedlichen Prozessen gebildet werden. Wir finden auch eine Korrelation zwischen den strukturellen Parametern von Scheiben und `Bulges', insbesondere zwischen effektivem Radius der `Bulges' und der Skalenlaenge der Scheiben in Systemen fruehen Typus. Wir interpretieren dies als Beweisstueck zugunsten von saekularen Evolutionsmodellen.

Galaxy formation is one of the most fascinating topics of modern cosmology. Since time immemorial, people have desired to understand the origin, motion and evolution of planets, stars and, more recently, galaxies and the Universe as a whole. Great advances in astronomy always have had impact on philosophy and redefined the self-understanding of mankind within the Universe. The first milestone on the long road of discoveries was undoubtedly the formulation of the laws of gravity and mechanics in 1687 by Newton. Einstein's extension of these laws in the years 1905 and 1913 led to a revolutionised understanding of space and time. In 1929 Hubble established the expanding Universe which subsequently led to the postulation of the hot Big Bang by Lemaitre (1934). Zwicky (1933) found that most of matter in the Universe is dark. The nature of this matter, interacting only through gravity and perhaps through the weak interaction, is still a mystery. Finally, Penzias and Wilson (1965) discovered the cosmic microwave background radiation, not only confirming the theory of the Big Bang, but also - as was observed later - revealing the origin of structure in the Universe. Today, cosmology and especially galaxy formation are fast paced exciting scientific fields. Surveys like the Sloan Digital Sky Survey will soon provide a catalogue of about 500 million galaxies with an unprecedent wealth of data. Deep observations with 8 or 10 m telescopes or with the Hubble Space telescope allow to observe objects in their very early evolutionary stages. In addition to this, the dramatic increase in computer power now allows us to carry out numerical experiments on galaxies and even on the large scale structure of the Universe. The latter is possible because of the extraordinary fact that as a result of microwave background observations the properties of the Universe some 300,000 years after the Big Bang are well known. As ordinary matter makes up only about ten percent of the total matter in the Universe, it can be neglected in simulations in a first approximation. An initial density field can then be evolved under the sole influence of gravity. The result of such simulations may be combined with semi-analytic models for the baryonic physics associated with galaxy formation. Gravity is a long range force, and it turns out that length scales of 100 Mpc or more have to be included in large scale structure simulations in order to obtain results that are representative for the Universe as a whole. The sizes of galaxies, however, are three to four orders of magnitude smaller than this so that numerical resolution has always been a concern in simulations which try to include galaxy formation. A clever and powerful trick alleviates this problem. After a low-resolution simulation has been performed, a small region of interest is selected and the simulation is run again, this time concentrating most of the computational effort on the small region, allowing the resolution to be increase dramatically without losing tidal influences from the large cosmological volume. This technique - called resimulation - is the driving force behind all the simulations that were performed for this thesis. After having run about 1500 supercomputer jobs it is clear that this technique is extremely powerful and allows the faithful simulation of objects that are far into the regime of non-linear evolution while taking into account the full cosmological context. In the first chapter of this work we briefly introduce aspects of the observable Universe and discuss the relevant theoretical background for this thesis. In the second chapter we use high-resolution simulations of structure formation to investigate the influence of the local environment of dark matter haloes on their properties. We run a series of four re-simulations of a typical, carefully selected representative region of the Universe so that we can explicitly check for convergence of the numerical results. In our highest resolution simulation we are able to resolve dark matter haloes as small as the one of the large Magellanic cloud. We propose a new method to estimate the density in the environment of a collapsed object and find weak correlations of the spin parameter and the concentration parameter with the local halo density. We find no such correlation for the halo shapes, the formation time and the last major merging event. In a second step we produce catalogues of model galaxies using a semi-analytic model of galaxy formation. We find correlations between the bulge-to-disk luminosity and the B-V colour index with the local environment. In chapter three we compare observations of the internal structure and kinematics of the eleven known satellites of the Milky Way with simulations of the formation of its dark halo in a LambdaCDM universe. Earlier work by Moore et al. 1999 and Klypin et al. 1999 claimed the cosmological concordance model of the Universe, the LambdaCDM model, to disagree with observations. The so-called "substructure-problem" is one of the two major challenges for this model and has attracted much attention. In order to remove the discrepancy, changes of the cosmological model have been proposed. We reinvestigate the substructure-problem using our ultra-high resolution simulations. For a galaxy-sized dark matter halo, our mass resolution is the highest resolution ever achieved. In contrast to the work of Moore et al. 1999 and Klypin et al. 1999, we find excellent agreement. The observed kinematics are exactly those predicted for stellar populations with the observed spatial structure orbiting within the most massive "satellite" substructures in our simulations. Less massive substructures have weaker potential wells than those hosting the observed satellites. If there is a halo substructure "problem", it consists in understanding why halo substructures have been so inefficient in making stars. We find that suggested modifications of dark matter properties (e.g. self-interacting or warm dark matter) may well spoil the good agreement found for standard Cold Dark Matter. If the dark matter in the Universe is made of weakly self-interacting particles, they may self-annihilate and emit gamma-rays. The detection of the gamma-ray signal would finally, after seventy years since its discovery, shed light on the nature of the dark matter. In chapter four we use our ultra-high resolution numerical simulations to estimate directly the annihilation flux from the central region of the Milky Way and from dark matter substructures in its halo. Such estimates remain uncertain because of their strong dependence on the structure of the densest regions of the halo. Our numerical experiments suggest, however, that less direct calculations have typically overestimated the emission from the centre of the Milky Way and from its halo's substructure. We find an overall enhancement of at most a factor of a few with respect to a smooth halo of standard NFW structure. For an observation outside the region around the galactic centre where the diffuse galactic gamma-ray background is dominant, GLAST can probe a large region of possible MSSM models. This result is independent of the exact structure of the innermost region of the Galaxy. Our analysis shows that the flux from the inner galaxy exceeds the expected contribution from the brightest substructure by a large factor. Nevertheless, for certain MSSM models substructure halos might be detectable with GLAST.