Podcasts about interferometer

fWotD Episode 2849: Virgo interferometer Welcome to Featured Wiki of the Day, your daily dose of knowledge from Wikipedia’s finest articles.The featured article for Friday, 21 February 2025 is Virgo interferometer.The Virgo interferometer is a large-scale scientific instrument near Pisa, Italy, for detecting gravitational waves. The detector is a Michelson interferometer, which can detect the minuscule length variations in its two 3-km (1.9 mi) arms induced by the passage of gravitational waves. The required precision is achieved using many systems to isolate it from the outside world, including keeping its mirrors and instrumentation in an ultra-high vacuum and suspending them using complex systems of pendula. Between its periodical observations, the detector is upgraded to increase its sensitivity. The observation runs are planned in collaboration with other similar detectors, including the two Laser Interferometer Gravitational-Wave Observatories (LIGO) in the United States and the Japanese Kamioka Gravitational Wave Detector (KAGRA), as cooperation between several detectors is crucial for detecting gravitational waves and pinpointing their origin.It was conceived and built when gravitational waves were only a prediction of general relativity. The project, named after the Virgo galaxy cluster, was first approved in 1992 and construction was completed in 2003. After several years of improvements without detection, it was shut down in 2011 for the "Advanced Virgo" upgrades. In 2015, the first observation of gravitational waves was made by the two LIGO detectors, while Virgo was still being upgraded. It resumed observations in early August 2017, making its first detection on 14 August (together with the LIGO detectors); this was quickly followed by the detection of the GW170817 gravitational wave, the only one also observed with classical methods (optical, gamma-ray, X-ray and radio telescopes) as of 2024.Virgo is hosted by the European Gravitational Observatory (EGO), a consortium founded by the French Centre National de la Recherche Scientifique (CNRS) and the Italian Istituto Nazionale di Fisica Nucleare (INFN). The broader Virgo Collaboration, gathering 940 members in 20 countries, operates the detector, and defines the strategy and policy for its use and upgrades. The LIGO and Virgo collaborations have shared their data since 2007, and with KAGRA since 2019, forming the LIGO-Virgo-KAGRA (LVK) collaboration.This recording reflects the Wikipedia text as of 00:51 UTC on Friday, 21 February 2025.For the full current version of the article, see Virgo interferometer on Wikipedia.This podcast uses content from Wikipedia under the Creative Commons Attribution-ShareAlike License.Visit our archives at wikioftheday.com and subscribe to stay updated on new episodes.Follow us on Mastodon at @wikioftheday@masto.ai.Also check out Curmudgeon's Corner, a current events podcast.Until next time, I'm long-form Ruth.

Did James Webb already reach its full potential or is there more to come from it? How does TESS compare to Kepler? Can we use Starlinks as a giant space-based interferometer? Can we rip a black hole apart to see what's inside? Answering all these questions and more in this week's Q&A!

Did James Webb already reach its full potential or is there more to come from it? How does TESS compare to Kepler? Can we use Starlinks as a giant space-based interferometer? Can we rip a black hole apart to see what's inside? Answering all these questions and more in this week's Q&A!

JWST has shown us what the modern infrared telescope is capable of. But it's not far-infrared. There are no space telescopes operating in that spectrum at the moment. But why? And what would we be able to see if we had one? Let's find out with Dr David Leisawitz, Chief at NASA Science Proposal Support Office.

JWST has shown us what the modern infrared telescope is capable of. But it's not far-infrared. There are no space telescopes operating in that spectrum at the moment. But why? And what would we be able to see if we had one? Let's find out with Dr David Leisawitz, Chief at NASA Science Proposal Support Office.

Ruby Payne-Scott is often called a pioneer in radio astronomy, but she was also a pioneer in advocating for women's rights. She was clearly brilliant, but her work was cut short by her desire to have a spouse and a family.  Erickson, Dorothy. “Payne-Scott, Ruby Violet (1912 - 1981).” THE ENCYCLOPEDIA OFWOMEN & LEADERSHIP IN TWENTIETH-CENTURY AUSTRALIA. https://www.womenaustralia.info/leaders/biogs/WLE0692b.htm M. Goss and Claire Hooker. “Payne-Scott, Ruby Violet (1912–1981).” Australian Dictionary of Biography, National Centre of Biography, Australian National University, https://adb.anu.edu.au/biography/payne-scott-ruby-violet-15036/text26233 Halleck, Rebecca. “Overlooked No More: Ruby Payne-Scott, Who Explored Space With Radio Waves.” New York Times. August 29, 2018. https://www.nytimes.com/2018/08/29/obituaries/ruby-payne-scott-overlooked.html “What is an Interferometer?” LIGO Caltech. https://www.ligo.caltech.edu/page/what-is-interferometer#:~:text=Interferometers%20are%20investigative%20tools%20used,%2Dmeter'%2C%20or%20interferometer. Marr, Jonathan M. et al. “Demonstrating the Principles of Aperture Synthesis with the Very Small Radio Telescope.” Bridgewater State University, Virtual Commons. Physics Faculty Publications. 2011. https://vc.bridgew.edu/cgi/viewcontent.cgi?article=1019&context=physics_fac#:~:text=In%20aperture%20synthesis%20a%20number,signals%20can%20also%20be%20added Robertson, Peter. “Pawsey, Joseph Lade (Joe) (1908–1962).” Australian Dictionary of Biography, National Centre of Biography, Australian National University. https://adb.anu.edu.au/biography/pawsey-joseph-lade-joe-11353/text2027 “Our History.” AWA Technology Services. http://www.awa.com.au/about-us/our-history/ “Hall (nee Payne Scott), Ruby Violet.” The Sydney Morning Herald. Obituaries. May 30, 1981. https://www.newspapers.com/image/122698551/?terms=Ruby%20Payne-Scott&match=1 Ward, Colin. “Ruby Payne-Scott [1912-1981].” CSIROpedia. March 23, 2011. https://csiropedia.csiro.au/payne-scott-ruby/ “Magnetism and Life.” For Worth Start Telegraph. March 29, 1936. https://www.newspapers.com/image/635960090/?terms=Ruby%20Payne%20Scott&match=1 Freeman, Joan. “A Passion for Physics: The Story of a Woman Physicist.” CRC Press. 1991. “Our History.” CSIRO. https://www.csiro.au/en/about/achievements/our-history Goss, W. M. and Richard McGee. “Under the Radar: The First The First Woman in Radio Astronomy: Ruby Payne-Scott.” Springer Science & Business Media. 2009. Goss, W. M. “Making Waves: The Story of Ruby Payne-Scott: Australian Pioneer Radio Astronomer.” Springer. 2013.  See omnystudio.com/listener for privacy information.

Historic Firsts: Arizona and the James Webb Telescope E31 On December 25, 2021, NASA launched the James Webb Space Telescope (JWST), the largest and most complex space telescope ever built. Four days later, Webb's massive sunshield deployed and within weeks, its primary mirror started unfurling. On August 12, 2022, Webb’s first images were released, and […] The post Historic Firsts: Arizona and the James Webb Telescope E31 appeared first on Business RadioX ®.

Over a billion lightyears ago, in the darkness of outer space, a collision of black holes sent out a fleet of invisible waves that were headed right toward planet Earth. The waves were so powerful they could ripple spacetime but most people on Earth didn't believe the waves were real. SPOILER ALERT: The waves are called gravitational waves and…they are real! Astrophysicist Dr. Wanda Díaz Merced tells the story of what happened when they hit Earth in 2015 and how scientists came to learn to use senses beyond eyesight to detect the waves. We also learn from Dr. Stavros Katsanevas about the building of a giant gravitational wave catcher called “The Interferometer.” This episode also explores how to persist in the face of doubt as we learn Wanda's tale of going blind and learning how to listen to the stars. Learn about the storytellers, listen to music, and dig deeper into the stories you hear on Terrestrials with activities you can do at home or in the classroom on our website, Terrestrialspodcast.org.  Watch the interferometer come to life, disco style, and find even MORE original Terrestrials fun on our Youtube. Badger us on Social Media: @radiolab and #TerrestrialsPodcast  More from Terrestrials  The Shovels: Dig Deeper For each episode of Terrestrials, we provide a selection of activity sheets, drawing prompts, musical lessons, and more. We call them “shovels” because we hope they will help you (and your friends, family, students, neighbors, etc) dig more deeply into the world! You can do them at home, in the classroom, outside, or in the privacy of your own mind. We hope you enjoy!If you want to share what you've made, ask an adult share it on social media using #TerrestrialsPodcast and make sure to tag @Radiolab Draw -  Use your ears to draw! In this very special drawing prompt, Wendy Mac and the DrawTogether team pull in an actual rockstar to play you various favorite sounds to draw. It's a feast for the mind, ears, and hands. Grab a pencil, pen, crayon, marker, anything, and check it out here! Play 🎶 - Learn how to play the chords to the song “UNIMAGINABLE” Do - Get crafty with a fun activity sheet!   This week's storyteller is Dr. Wanda Díaz Merced. Want to keep learning? Check out these resources to learn about the time-bending power that is the gravitational wave: Get to Wanda a little better; watch her TED talk!Take a tour of the world's first interferometer! (Free monthly tours in person in Richland, WA)Train yourself to use sound for signal detection in astronomy. Learn more about asteroseismology with the wonderful Hank Green!Spooked by the idea of the infinite universe? Listen to John Green's “Against Nihilism” (probably best for 13 and up)! Terrestrials is a production of WNYC Studios, created by Lulu Miller. This episode is produced by Ana González, Alan Goffinski and Lulu Miller. Original Music by Alan Goffinski. Help from Suzie Lechtenberg, Sarah Sandbach, Natalia Ramirez, and Sarita Bhatt. Fact-check by Natalie Meade. Sound design by Phoebe Wang with additional engineering by Joe Plourde. Our storytellers this week are Dr. Wanda Díaz Merced and Dr. Stavros Katsanevas. Transcription by Caleb Codding. Our advisors are Theanne Griffith, Aliyah Elijah, Dominique Shabazz, John Green, Liza Steinberg-Demby, Alice Wong, and Tara Welty. Terrestrials is supported in part by Science Sandbox, an initiative of the Simons Foundation. Have questions for us, badgers? Badger us away! Your parent/guardian should write to us along with you, so we know you have their permission, and for maybe even having your ideas mentioned on the show. Email terrestrials@wnyc.org

What does an interferometer really measure? Including instrument and data characteristics in the reconstruction of the 21cm power spectrum by Adélie Gorce et al. on Monday 10 October Combining the visibilities measured by an interferometer to form a cosmological power spectrum is a complicated process in which the window functions play a crucial role. In a delay-based analysis, the mapping between instrumental space, made of per-baseline delay spectra, and cosmological space is not a one-to-one relation. Instead, neighbouring modes contribute to the power measured at one point, with their respective contributions encoded in the window functions. To better understand the power spectrum measured by an interferometer, we assess the impact of instrument characteristics and analysis choices on the estimator by deriving its exact window functions, outside of the delay approximation. Focusing on HERA as a case study, we find that observations made with long baselines tend to correspond to enhanced low-k tails of the window functions, which facilitate foreground leakage outside the wedge, whilst the choice of bandwidth and frequency taper can help narrow them down. With the help of simple test cases and more realistic visibility simulations, we show that, apart from tracing mode mixing, the window functions can accurately reconstruct the power spectrum estimator of simulated visibilities. We note that the window functions depend strongly on the chromaticity of the beam, and less on its spatial structure - a Gaussian approximation, ignoring side lobes, is sufficient. Finally, we investigate the potential of asymmetric window functions, down-weighting the contribution of low-k power to avoid foreground leakage. The window functions presented in this work correspond to the latest HERA upper limits for the full Phase I data. They allow an accurate reconstruction of the power spectrum measured by the instrument and can be used in future analyses to confront theoretical models and data directly in cylindrical space. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.03721v1

What does an interferometer really measure? Including instrument and data characteristics in the reconstruction of the 21cm power spectrum by Adélie Gorce et al. on Monday 10 October Combining the visibilities measured by an interferometer to form a cosmological power spectrum is a complicated process in which the window functions play a crucial role. In a delay-based analysis, the mapping between instrumental space, made of per-baseline delay spectra, and cosmological space is not a one-to-one relation. Instead, neighbouring modes contribute to the power measured at one point, with their respective contributions encoded in the window functions. To better understand the power spectrum measured by an interferometer, we assess the impact of instrument characteristics and analysis choices on the estimator by deriving its exact window functions, outside of the delay approximation. Focusing on HERA as a case study, we find that observations made with long baselines tend to correspond to enhanced low-k tails of the window functions, which facilitate foreground leakage outside the wedge, whilst the choice of bandwidth and frequency taper can help narrow them down. With the help of simple test cases and more realistic visibility simulations, we show that, apart from tracing mode mixing, the window functions can accurately reconstruct the power spectrum estimator of simulated visibilities. We note that the window functions depend strongly on the chromaticity of the beam, and less on its spatial structure - a Gaussian approximation, ignoring side lobes, is sufficient. Finally, we investigate the potential of asymmetric window functions, down-weighting the contribution of low-k power to avoid foreground leakage. The window functions presented in this work correspond to the latest HERA upper limits for the full Phase I data. They allow an accurate reconstruction of the power spectrum measured by the instrument and can be used in future analyses to confront theoretical models and data directly in cylindrical space. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.03721v1

The dust sublimation region of the Type 1 AGN NGC4151 at a hundred micro-arcsecond scale as resolved by the CHARA Array interferometer by Makoto Kishimoto et al. on Wednesday 14 September The nuclear region of Type 1 AGNs has only been partially resolved so far in the near-infrared (IR) where we expect to see the dust sublimation region and the nucleus directly without obscuration. Here we present the near-IR interferometric observation of the brightest Type 1 AGN NGC4151 at long baselines of ~250 m using the CHARA Array, reaching structures at hundred micro-arcsecond scales. The squared visibilities decrease down to as low as ~0.25, definitely showing that the structure is resolved. Furthermore, combining with the previous visibility measurements at shorter baselines but at different position angles, we show that the structure is elongated *perpendicular* to the polar axis of the nucleus, as defined by optical polarization and a linear radio jet. A thin-ring fit gives a minor/major axis ratio of ~0.7 at a radius ~0.5 mas (~0.03 pc). This is consistent with the case where the sublimating dust grains are distributed preferentially in an equatorial plane in a ring-like geometry, viewed at an inclination angle of ~40 deg. Recent mid-IR interferometric finding of polar-elongated geometry at a pc scale, together with a larger-scale polar outflow as spectrally resolved by the HST, would generally suggest a dusty, conical and hollow outflow being launched presumably in the dust sublimation region. This might potentially lead to a polar-elongated morphology in the near-IR, as opposed to the results here. We discuss a possible scenario where an episodic, one-off anisotropic acceleration formed a polar-fast and equatorially-slow velocity distribution, having lead to an effectively flaring geometry as we observe. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.06061v1

The dust sublimation region of the Type 1 AGN NGC4151 at a hundred micro-arcsecond scale as resolved by the CHARA Array interferometer by Makoto Kishimoto et al. on Wednesday 14 September The nuclear region of Type 1 AGNs has only been partially resolved so far in the near-infrared (IR) where we expect to see the dust sublimation region and the nucleus directly without obscuration. Here we present the near-IR interferometric observation of the brightest Type 1 AGN NGC4151 at long baselines of ~250 m using the CHARA Array, reaching structures at hundred micro-arcsecond scales. The squared visibilities decrease down to as low as ~0.25, definitely showing that the structure is resolved. Furthermore, combining with the previous visibility measurements at shorter baselines but at different position angles, we show that the structure is elongated *perpendicular* to the polar axis of the nucleus, as defined by optical polarization and a linear radio jet. A thin-ring fit gives a minor/major axis ratio of ~0.7 at a radius ~0.5 mas (~0.03 pc). This is consistent with the case where the sublimating dust grains are distributed preferentially in an equatorial plane in a ring-like geometry, viewed at an inclination angle of ~40 deg. Recent mid-IR interferometric finding of polar-elongated geometry at a pc scale, together with a larger-scale polar outflow as spectrally resolved by the HST, would generally suggest a dusty, conical and hollow outflow being launched presumably in the dust sublimation region. This might potentially lead to a polar-elongated morphology in the near-IR, as opposed to the results here. We discuss a possible scenario where an episodic, one-off anisotropic acceleration formed a polar-fast and equatorially-slow velocity distribution, having lead to an effectively flaring geometry as we observe. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.06061v1

Performance of the upgraded VERITAS Stellar Intensity Interferometer VSII by David B. Kieda et al. on Thursday 08 September The VERITAS Imaging Atmospheric Cherenkov Telescope array (IACT) was augmented in 2019 with high-speed focal plane electronics to create a new Stellar Intensity Interferometry (SII) observational capability (VERITAS-SII, or VSII). VSII operates during bright moon periods, providing high angular resolution observations ( < 1 mas) in the B photometric band using idle telescope time. VSII has already demonstrated the ability to measure the diameters of two B stars at 416 nm (Bet CMa and Eps Ori) with < 5% accuracy using relatively short (5 hours) exposures. The VSII instrumentation was recently improved to increase instrumental sensitivity and observational efficiency. This paper describes the upgraded VSII instrumentation and documents the ongoing improvements in VSII sensitivity. The report describes VSII's progress in extending SII measurements to dimmer magnitude stars and improving the VSII angular diameter measurement resolution to better than 1%. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2209.03453v1

Today, you'll learn about how orangutans use slang a lot like we do, what causes and can alleviate everyday motion sickness, and how one black hole kicked another across the galaxy.Orangutans are dope.“Orangutans use Slang to Show off Their “Coolness”, Study Suggests" by Nicola Davishttps://www.theguardian.com/science/2022/mar/21/orangutans-use-slang-to-show-off-their-coolness-study-suggests“Orangutan Squeaks Reveal Language Evolution Says Study" by Victoria Gillhttps://www.bbc.com/news/science-environment-38907681“What did Language Grow From? Ape Hands, Mouths, or Both? – Kristen Marie Gillespie-Lynch, Emily Sue Savage-Rumbaugh, Heidi Lyn, and Patricia Greenfieldhttps://kids.frontiersin.org/articles/10.3389/frym.2019.00061“Apes Communicate, Humans Have Language" by Max Planck Institutehttps://www.cbs.mpg.de/research-topics/language-interviewA solution beyond not looking at your phone.“How To Fight Motion Sickness — And The Scientific Reason Some People Suffer More” By Saima Rajasingamhttps://www.inverse.com/mind-body/motion-sickness-treatment“A study of cybersickness and sensory conflict theory using a motion-coupled virtual reality system” by Adrian K.T. Ng, Leith K.Y. Chan, Henry Y.K. Lauhttps://www.sciencedirect.com/science/article/abs/pii/S0141938218300301Soccer but with black holes.“Gravitational waves gave a new black hole a high-speed ‘kick'” By Emily Conoverhttps://www.sciencenews.org/article/black-hole-gravitational-waves-kick-ligo-merger-spacetime“A black hole formed by a lopsided merger may have gone rogue” By Robert Leahttps://www.space.com/black-hole-escaping-galaxy-from-collision“Ripples in spacetime: Science's 2016 Breakthrough of the Year” by Adrian Chohttps://www.science.org/content/article/ripples-spacetime-sciences-2016-breakthrough-year“How Scientists Captured the First Image of a Black Hole” by Ota Lutzhttps://www.jpl.nasa.gov/edu/news/2019/4/19/how-scientists-captured-the-first-image-of-a-black-hole/“What is an Interferometer?” by the Laser Interferometer Gravitational-wave Observatoryhttps://www.ligo.caltech.edu/page/what-is-interferometerFollow Curiosity Daily on your favorite podcast app to get smarter with Calli and Nate — for free! 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.Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/orangu-slang-easing-car-queasing-kicked-across-space

In unserer heutigen Folge geht es um Atominterferometer. Man kann statt Laserlicht auch einfach Materiewellen nutzen und damit Interferometrie betreiben. Wie das genau funktioniert und was das für Vorteile haben kann, erfahrt ihr hier! Viel Vergnügen! #atominterferometer #materiewellen #interferometer #gravitationswellen

Dr Daniel Brown and his colleagues at the ARC Centre of Excellence for Gravitational Wave Discovery in Adelaide have rebuilt one of the key observatories they use to detect gravitational waves inside the game of Minecraft. It's part of the Australian National Science Week, and they'll be giving audiences a guided tour of the device in game and live streamed on YouTube. The next tour is open on Saturday 22nd of August, at 2:00pm local Adelaide time, which is 12:30PM in Western Australia, and 2:30PM Australian Eastern Standard time and you can RSVP on Eventbrite here: Exploring Gravitational Wave Observatories in Minecraft You can join the server directly in Minecraft Java Edition by opening the following server address: minecraft.ozgrav.org:25593 You can find a written version of this story on the Pixel Sift website: Aussie scientists use Minecraft to build a replica gravitational wave observatory and you can visit it during Science Week See omnystudio.com/policies/listener for privacy information.

This PhysCast calculates the phase difference between two beams of light that have travelled a different distance.

01:11 Is our Sun capable of releasing a super flare? 04:10 How much for a decent starting telescope? 05:20 Is terraforming Mars pointless? 07:08 Will alien life exist in the future? 09:03 Will Dobsonians work in a city? 09:45 What is the space race trying to achieve? 12:31 Can an artificial magnetic field stop space radiation? 14:04 Would I go to Mars? 14:38 Interferometer the size of Mars' orbit? 17:06 Why build bigger telescopes? 18:32 Why isn't everything expanding? 20:18 When is the next Decadal Survey? 21:35 Live telescopes? 21:57 Should we have an international space agency? 23:57 Is there a theoretical upper limit to black holes? 24:20 What will we accomplish in the next 100 years? 25:32 Life on Titan? 27:32 Did we capture any planets or moons from outside the Solar System? 28:32 Can I retire on Mars in 30 years? 29:59 How would we capture an asteroid to mine it? 31:16 Why don't we search for other kinds of life? 33:30 Simulation theory? 36:02 Haven't we tried reusable rockets before? 37:18 Geoengineering to stop global warming? 39:20 Did life ever exist on Mars? 40:43 Any viewers outside the US? 41:34 Any big errors I've made? 43:20 When will we start asteroid mining? 44:27 When will we get a bloopers episode? 45:02 Most exciting project? 47:00 What about Venus? 48:43 Any cancelled projects that make me sad? 49:43 Can we plant trees on other planets? 51:18 Will spacesuits get better? 53:13 Will Mars spacesuits protect from radiation? 54:11 My opinion of nuclear energy? 55:45 Travel to space in our lifetime? 56:25 Will I do a small QA tour? 57:01 Does my wife love space too? 58:10 Does a 2024 Moon landing make sense?Support Universe Today Podcast

01:11 Is our Sun capable of releasing a super flare? 04:10 How much for a decent starting telescope? 05:20 Is terraforming Mars pointless? 07:08 Will alien life exist in the future? 09:03 Will Dobsonians work in a city? 09:45 What is the space race trying to achieve? 12:31 Can an artificial magnetic field stop space radiation? 14:04 Would I go to Mars? 14:38 Interferometer the size of Mars' orbit? 17:06 Why build bigger telescopes? 18:32 Why isn't everything expanding? 20:18 When is the next Decadal Survey? 21:35 Live telescopes? 21:57 Should we have an international space agency? 23:57 Is there a theoretical upper limit to black holes? 24:20 What will we accomplish in the next 100 years? 25:32 Life on Titan? 27:32 Did we capture any planets or moons from outside the Solar System? 28:32 Can I retire on Mars in 30 years? 29:59 How would we capture an asteroid to mine it? 31:16 Why don't we search for other kinds of life? 33:30 Simulation theory? 36:02 Haven't we tried reusable rockets before? 37:18 Geoengineering to stop global warming? 39:20 Did life ever exist on Mars? 40:43 Any viewers outside the US? 41:34 Any big errors I've made? 43:20 When will we start asteroid mining? 44:27 When will we get a bloopers episode? 45:02 Most exciting project? 47:00 What about Venus? 48:43 Any cancelled projects that make me sad? 49:43 Can we plant trees on other planets? 51:18 Will spacesuits get better? 53:13 Will Mars spacesuits protect from radiation? 54:11 My opinion of nuclear energy? 55:45 Travel to space in our lifetime? 56:25 Will I do a small QA tour? 57:01 Does my wife love space too? 58:10 Does a 2024 Moon landing make sense?

In dieser Folge des Podcasts erfahrt ihr mehr über die Techniken, mit denen moderne Gravitationswellendetektoren ihre enormen Sensitivitäten erreichen und damit die Gravitationswellenastronomie erst möglich machen..

Richard Gillette, W9PE, is the consummate ham radio operator and mentor, IEEE speaker, and frequent contributor to our amateur radio hobby from his many articles in the ham radio magazines.  His own website, w9pe.us, is an amazing resource, including his Excel based test equipment simulator for anyone wanting to teach the fundamentals of ham radio in a one day or weekend “ham cram” course.   W9PE shares over 60 years of his ham radio experience in this QSO Today.

Topics Discussed: Keurig Trance Brewing in 3D, Thermos Coffee Cup, Remembering Valentine's Day, Celebrating Science: Gravitational Waves, Einstein's Theory of Relativity, Black Holes, Interferometer, Wave Frequencies, Humans Leveling Up, Man Killed by Falling Meteorite, Space Sacrifices in Exchange for Universal Knowledge, A Terrible Decision to Make, Checking and Balancing God-like Abilities, Word of the Day, Great Falls' Sonic and Salmon Hatchery, the Problem with Photography, A Khaki Cargo Pant Deficit, Mall Fatigue, Deadpool, Valentine's Card and Candy, Bringing Back Vinegar Valentines, CMFE Science: Hugo de Garis and Evolvable Hardware, Humans are Computers Taken Further, Cylon Drones and Coming Civil War in Tech, Best Standards and Practices  for AI, and The Push to 200!

Poudereux Sánchez, D (Technical University of Madrid) Friday 05 July 2013, 11:45-12:00

Poudereux Sánchez, D (Technical University of Madrid) Friday 05 July 2013, 11:45-12:00

This thesis is divided into two parts: an instrumentation part and an astrophysical part. The instrumentation part describes the development and implementation of the fiber coupler and guiding subsystems of the 2nd generation VLTI instrument GRAVITY. The astrophysical part describes the derivation of the star formation history of the Milky Way’s nuclear star cluster based on imaging and spectroscopic data obtained at the Very Large Telescope. The future VLTI instrument GRAVITY will deliver micro-arcsecond astrometry, using the interferometric combination of four telescopes. The instrument is a joint project of several European institutes lead by the Max Planck Institut f¨ur extraterrestrische Physik. The instrumental part of this thesis describes the fiber coupler unit and the guiding system. They serve for beam stabilization and light injection in GRAVITY. In order to deliver micro-arcsecond astrometry, GRAVITY requires an unprecedented stability of the VLTI optical train. We therefore developed a dedicated guiding system, correcting the longitudinal and lateral pupil wanderas well as the image jitter in VLTI tunnel. The actuators for the correction are provided by four fiber coupler units located in the GRAVITY cryostat. Each fiber coupler picks the light of one telescope and stabilizes the beam. Furthermore each unit provides field de-rotation, polarization adjustment as well as atmospheric piston correction. A novel roof-prism design offers the possibility of on-axis as well as off-axis fringe tracking. Finally the stabilized beam is injected with minimized losses into singlemode fibers via parabolic mirrors. We present lab results of the first guiding- as well as the first fiber coupler prototype, in particular the closed loop performance and the optical quality. Based on the lab results we derive the on-sky performance of the systems and the implications concerning the sensitivity of GRAVITY. The astrophysical part of this thesis presents imaging and integral field spectroscopy data for 450 cool giant stars within 1 pc from Sgr A*. We use the prominent CO bandheads to derive effective temperatures of individual giants. Additionally we present the deepest spectroscopic observation of the Galactic Center so far, probing the number of B9/A0 main sequence stars (2.2 − 2.8M) in two deep fields. From spectro-photometry we construct a Hertzsprung-Russell diagram of the red giant population and fit the observed diagram with model populations to derive the star formation history of the nuclear cluster. We find that (1) the average nuclear star-formation rate dropped from an initial maximum 10Gyrs ago to a deep minimum 1-2Gyrs ago and increased again during the last few hundred Myrs, and (2) that roughly 80% of the stellar mass formed more than 5Gyrs ago; (3) mass estimates within R 1 pc from Sgr A* favor a dominant star formation mode with a normal Chabrier/Kroupa initial mass function for the majority of the past star formation in the Galactic Center. The bulk stellar mass seems to have formed under conditions significantly different from the observed young stellar disks, perhaps because at the time of the formation of the nuclear cluster the massive black hole and its sphere of influence was much smaller than today.

We look at the transmission of a Fabry-Perot interferometer and discuss properties like the free spectral range, finesse and linewidth.

We investigate the Michelson interferometer and the relationship between physical parameters and the interference term.