AAS NEWSLETTER Issue 127 a Publication for the Members of the American Astronomical Society
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Is the Universe Expanding?: an Historical and Philosophical Perspective for Cosmologists Starting Anew
Western Michigan University ScholarWorks at WMU Master's Theses Graduate College 6-1996 Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew David A. Vlosak Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses Part of the Cosmology, Relativity, and Gravity Commons Recommended Citation Vlosak, David A., "Is the Universe Expanding?: An Historical and Philosophical Perspective for Cosmologists Starting Anew" (1996). Master's Theses. 3474. https://scholarworks.wmich.edu/masters_theses/3474 This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. IS THEUN IVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STAR TING ANEW by David A Vlasak A Thesis Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements forthe Degree of Master of Arts Department of Philosophy Western Michigan University Kalamazoo, Michigan June 1996 IS THE UNIVERSE EXPANDING?: AN HISTORICAL AND PHILOSOPHICAL PERSPECTIVE FOR COSMOLOGISTS STARTING ANEW David A Vlasak, M.A. Western Michigan University, 1996 This study addresses the problem of how scientists ought to go about resolving the current crisis in big bang cosmology. Although this problem can be addressed by scientists themselves at the level of their own practice, this study addresses it at the meta level by using the resources offered by philosophy of science. There are two ways to resolve the current crisis. -
Astronomy 142, Spring 2013 2 April 2013
Astronomy 142, Spring 2013 2 April 2013 Today in Astronomy 142: distances to the galaxies Standard candles and standard rulers. Cepheids, and Henrietta Leavitt’s invention of standard candles. The extragal acti c nature of the spiral nebulae and the Shapley-Curtis debate. Type Ia supernovae as standard candles. The extragalactic distance The Small Magellanic Cloud, site of the scale. discovery of Leavitt’s Law. (Photograph by Weihao Wang (NRAO).) 2 April 2013 Astronomy 142, Spring 2013 1 Standard candles and standard rulers There’s only one direct distance measurement method for individual objects more than a few light-hours away – trig parallax – and it only works on objects within a few hundred parsecs, these days. (> 10 kpc, after Gaia is deployed.) Distance being key, astronomers have often sought standard candles or rulers to aid in its determination. Standard candle: an object with a well-determined luminosity L known a priori, whose distance is therefore rLf4(or equivalently 5log r10 pc mM ) . Standard ruler: an object with length d perpendicular to the line of sight is known a priori, whose distance is rdsin d . 2 April 2013 Astronomy 142, Spring 2013 2 Henrietta Leavitt and standard candles Today tens of thousands of Cepheid variable stars are known, a large fraction of which – about 2400 – were discovered by Henrietta Leavitt, perhaps the most illustrious of the women Henrietta Swan Leavitt (AIP photo) who worked as “computers” in Edward Pickering’s group at Harvard College Observatory. 969 of them are in the Small Magellanic Cloud (Leavitt 1908), and therefore all about the same distance (~60 kpc). -
Student Exploration: Big Bang Theory – Hubble's
McCarthy Physical Science 2017 Name: Date: Student Exploration: Big Bang Theory – Hubble’s Law Vocabulary: absolute brightness, absorption spectrum, apparent brightness, Big Bang theory, blueshift, Cepheid variable, Doppler shift, Hubble constant, Hubble’s law, luminosity, megaparsec, period, redshift, spectrograph Prior Knowledge Questions (Do these BEFORE using the Gizmo.) Standing by the side of a lonely highway at night, you see two motorcycle headlights, one in each direction. The headlight on your left appears brighter than the one on your right. 1. If the headlights are equally bright, which motorcycle is closer? Explain: 2. Suppose the dim-looking headlight on the right is actually a small light on the front of a bicycle. What can you conclude about the distance of the motorcycle and bicycle? Gizmo Warm-up In 1912, an astronomer named Henrietta Swan Leavitt studied a class of stars called Cepheid variables. These stars change from bright to dim to bright again. Her discoveries led to a method of measuring distances to other galaxies and eventually helped to support the Big Bang theory of the origin of the universe. In the Big Bang Theory – Hubble’s Law Gizmo™, select Region A. Look at the image of the Andromeda Galaxy, a galaxy relatively close to our own Milky Way galaxy. 1. Locate the two Cepheid variables, the stars that change in brightness over time. Star A-091 is the yellow star, and A-171 is the white star. A. Which star reaches a greater apparent brightness? B. Which star takes longer to pulse? 2. Because both stars are in the same galaxy, they are about the same distance from Earth. -
00:00 [Narrator] 1. the NASA/ESA Hubble Space Telescope Is Named After the Famous Astronomer Edwin Hubble. He Discovered That T
Keywords: Distances, Cepheids, Henrietta Leavitt Hubblecast Episode 116: Henrietta Leavitt — the woman Visual notes who measured the Universe 00:00 [Narrator] 1. The NASA/ESA Hubble Space Telescope is named after the famous astronomer Edwin Hubble. He discovered that there are galaxies outside of our own and that the Universe is expanding. However, these remarkable discoveries wouldn’t have been possible without one exceptional astronomer before him — Henrietta Swan Leavitt. 00:30 2. Henrietta Leavitt — the woman who measured the Universe 00:40 [Narrator] 3. Henrietta Leavitt was born in Lancaster, Massachusetts in 1868. She studied at Oberlin College, Ohio, and then Harvard University's Society for the Collegiate Instruction of Women. It wasn’t until her final year at university that she began to study astronomy — but this sparked a keen interest that she would pursue for the rest of her life. 01:10 4.She began to work at Harvard Observatory as a “computer” — one of several skilled women hired to process astronomical data. She helped with cataloguing the brightness of every measurable star and was quickly promoted to be head of the photographic stellar photometry department. 01:34 5. Supplied with photographic plates of the stars in the southern sky, Leavitt was tasked with classifying variable stars — ones that fluctuate in brightness. 01:47 6. While studying these changing stars she noticed a pattern: the brighter the star, the longer the period of the fluctuations. The easily measured length of the star’s fluctuations directly leads to its brightness — and to its distance. The observation of these Cepheid variables turned out to be the key to a fundamental change in our understanding of the Universe. -
The History of Star Formation in Galaxies
Astro2010 Science White Paper: The Galactic Neighborhood (GAN) The History of Star Formation in Galaxies Thomas M. Brown ([email protected]) and Marc Postman ([email protected]) Space Telescope Science Institute Daniela Calzetti ([email protected]) Dept. of Astronomy, University of Massachusetts 24 25 26 I 27 28 29 30 0.5 1.0 1.5 V-I Brown et al. The History of Star Formation in Galaxies Abstract If we are to develop a comprehensive and predictive theory of galaxy formation and evolution, it is essential that we obtain an accurate assessment of how and when galaxies assemble their stel- lar populations, and how this assembly varies with environment. There is strong observational support for the hierarchical assembly of galaxies, but by definition the dwarf galaxies we see to- day are not the same as the dwarf galaxies and proto-galaxies that were disrupted during the as- sembly. Our only insight into those disrupted building blocks comes from sifting through the re- solved field populations of the surviving giant galaxies to reconstruct the star formation history, chemical evolution, and kinematics of their various structures. To obtain the detailed distribution of stellar ages and metallicities over the entire life of a galaxy, one needs multi-band photometry reaching solar-luminosity main sequence stars. The Hubble Space Telescope can obtain such data in the outskirts of Local Group galaxies. To perform these essential studies for a fair sample of the Local Universe will require observational capabilities that allow us to extend the study of resolved stellar populations to much larger galaxy samples that span the full range of galaxy morphologies, while also enabling the study of the more crowded regions of relatively nearby galaxies. -
A Remarkable Panoramic Space Telescope for the 2020'S
A Remarkable Panoramic Space Telescope for the 2020s Dr. Marc Postman (SB ’81, MIT) Space Telescope Science Institute How are stars and galaxies formed? How does the universe work? Astronomers ask big questions. Are we alone? WFIRST: Wide Field Infrared Survey Telescope Dark Energy, Dark Wide-Field Surveys of the Matter, and the Fate of the Universe Universe ? ? Technology Development for The full distribution of planets around stars Exploration of New Worlds National Academy of Sciences Astronomy & Astrophysics Decadal Survey (2010) DARK MATTER DARK ENERGY 26% 69% STARS, GAS, DUST, ALL WE CAN SEE 5% How do we know there is so much dark matter? And what could dark matter be? How do we know there is so much dark energy? And what is it? Do we need new physics? What new experiments do we need to run? What new observations do we need to make? Basic properties of dark matter… • Dark matter is likely a particle, the way protons and neutrons are particles. • These particles must be abundant. • Dark matter barely interacts, if at all, with other matter (except by gravity). • Dark matter does not emit light. • Dark matter is passing through each of us right now (about 3 x 10-7 micrograms every second)*. *Based on E. Siegel, Forbes We already know dark matter cannot be: • Black holes • Neutrinos • Dwarf planets • Cosmic dust • Squirrels https://xkcd.com/2186/ Cluster of galaxies We can measure the mass in a system by measuring orbital speeds and distances 60 50 Mercury 40 Venus 30 Earth Mars 20 Jupiter Orbital Velocity (km/s) Velocity Orbital 10 -
Cluster Lensing and Supernova Survey with Hubble
Cluster Lensing And Supernova survey with Hubble Marc Postman, STScI LBL Physics Division RPM, May 20, 2014 Cluster Lensing And Supernova survey with Hubble CLASH Team at RAS, London, Sept 2013 A HST Multi-Cycle Treasury Program designed to place new constraints on the fundamental components of the cosmos: dark matter, dark energy, and baryons. To accomplish this, we are using galaxy clusters as cosmic lenses to probe dark matter and magnify distant galaxies. Multiple observation epochs enable a z > 1 SN search in the surrounding field (where lensing magnification is low). The CLASH Science Team: ~60 researchers, 30 institutions, 12 countries Marc Postman, P.I. Space Telescope Science Institute (STScI) Ofer Lahav UCL Begona Ascaso UC Davis Ruth Lazkoz Univ. of the Basque Country Italo Balestra Max Plank Institute (MPE) Doron Lemze JHU Matthias Bartelmann Universität Heidelberg Dan Maoz Tel Aviv University Narciso “Txitxo” Benitez Instituto de Astrofisica de Andalucia (IAA) Curtis McCully Rutgers University Andrea Biviano INAF - OATS Elinor Medezinski JHU Rychard Bouwens Leiden University Peter Melchior The Ohio State University Larry Bradley STScI Massimo Meneghetti INAF / Osservatorio Astronomico di Bologna Thomas Broadhurst Univ. of the Basque Country Amata Mercurio INAF / OAC Dan Coe STScI Julian Merten JPL / Caltech Thomas Connor Michigan State University Anna Monna Univ. Sternwarte Munchen / MPE Mauricio Carrasco Universidad Catolica de Chile Alberto Molino IAA Nicole Czakon California Institute of Technology / ASIAA John Moustakas -
Meeting Program
A A S MEETING PROGRAM 211TH MEETING OF THE AMERICAN ASTRONOMICAL SOCIETY WITH THE HIGH ENERGY ASTROPHYSICS DIVISION (HEAD) AND THE HISTORICAL ASTRONOMY DIVISION (HAD) 7-11 JANUARY 2008 AUSTIN, TX All scientific session will be held at the: Austin Convention Center COUNCIL .......................... 2 500 East Cesar Chavez St. Austin, TX 78701 EXHIBITS ........................... 4 FURTHER IN GRATITUDE INFORMATION ............... 6 AAS Paper Sorters SCHEDULE ....................... 7 Rachel Akeson, David Bartlett, Elizabeth Barton, SUNDAY ........................17 Joan Centrella, Jun Cui, Susana Deustua, Tapasi Ghosh, Jennifer Grier, Joe Hahn, Hugh Harris, MONDAY .......................21 Chryssa Kouveliotou, John Martin, Kevin Marvel, Kristen Menou, Brian Patten, Robert Quimby, Chris Springob, Joe Tenn, Dirk Terrell, Dave TUESDAY .......................25 Thompson, Liese van Zee, and Amy Winebarger WEDNESDAY ................77 We would like to thank the THURSDAY ................. 143 following sponsors: FRIDAY ......................... 203 Elsevier Northrop Grumman SATURDAY .................. 241 Lockheed Martin The TABASGO Foundation AUTHOR INDEX ........ 242 AAS COUNCIL J. Craig Wheeler Univ. of Texas President (6/2006-6/2008) John P. Huchra Harvard-Smithsonian, President-Elect CfA (6/2007-6/2008) Paul Vanden Bout NRAO Vice-President (6/2005-6/2008) Robert W. O’Connell Univ. of Virginia Vice-President (6/2006-6/2009) Lee W. Hartman Univ. of Michigan Vice-President (6/2007-6/2010) John Graham CIW Secretary (6/2004-6/2010) OFFICERS Hervey (Peter) STScI Treasurer Stockman (6/2005-6/2008) Timothy F. Slater Univ. of Arizona Education Officer (6/2006-6/2009) Mike A’Hearn Univ. of Maryland Pub. Board Chair (6/2005-6/2008) Kevin Marvel AAS Executive Officer (6/2006-Present) Gary J. Ferland Univ. of Kentucky (6/2007-6/2008) Suzanne Hawley Univ. -
Henrietta Leavitt
2 HENRIETTA LEAVITT BIOGRAPHY 980L HENRIETTA LEAVITT MEASURING DISTANCE IN THE UNIVERSE Born Died July 4, 1868 December 12, 1921 Lancaster, Massachusetts Cambridge, Massachusetts By Cynthia Stokes Brown, adapted by Newsela Henrietta Swan Leavitt studied distant stars that dim and brighten. These are called Cepheid variable stars. She made it possible for others to measure huge cosmic distances, discover additional galaxies, and begin mapping the Universe. 2 3 \Leavitt was a minister’s daughter. Her family moved frequently. period ranges from about one day to nearly four months. She attended the Society for Collegiate Instruction of Women, which is Leavitt studied thousands of photographs of these stars. She discovered now part of Harvard University. It was a school she had dreamed of a way to determine how bright they are and how far away they are. attending. In her senior year she discovered her calling — astronomy. She found that the longer a star’s period, the brighter it was. By comparing how bright a star appeared, and how bright it actually was, Leavitt could estimate how much of the star’s light had been lost while reaching Earth, At the Harvard College Observatory and how far away the star actually was. Leavitt liked astronomy so much that after graduation she became a volun- Leavitt published her first paper on the period-luminosity relationship in teer at the Harvard College Observatory as a “computer.” This was the 1908. Four years after that she published a table of the periods of 25 name used for women who examined tiny dots on photographs of the night Cepheid variables. -
Keiichi Umetsu — CURRICULUM VITAE (Updated on July 8, 2021)
Keiichi Umetsu —CURRICULUM VITAE (Updated on September 8, 2021) Contact and Personal Information Work Address: Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), 11F of Astronomy-Mathematics Building, National Taiwan University (NTU), No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan Email: [email protected] Web: http://idv.sinica.edu.tw/keiichi/index.php ORCID: 0000-0002-7196-4822 WOS ResearcherID: AAZ-7589-2020 Academic Appointments Full Research Fellow [rank equivalent to Full Professor], ASIAA (01/2014 – present) Kavli Visiting Scholar, Kavli Institute for Astronomy and Astrophysics, Peking University, China (2016) Associate Research Fellow [tenured], ASIAA (01/2010 – 12/2013) Adjunct Research Fellow, Leung Center for Cosmology and Particle Astrophysics, NTU (01/2008 – 12/2012) Assistant Research Fellow [tenure track], ASIAA (06/2006 – 12/2009) Science Lead for the Yuan Tseh Lee Array: AMiBA, Mauna Loa, Hawaii, USA (08/2005 – 07/2011) Faculty Staff Scientist, ASIAA (07/2005 – 05/2006) Postdoctoral Research Fellow, ASIAA (06/2001 – 06/2005) Education Ph.D. in Astronomy, Tohoku University, Japan (04/1998 – 03/2001) M.Sc. in Astronomy, Tohoku University, Japan (04/1996 – 03/1998) B.Sc. in Physics, Tohoku University, Japan (04/1992 – 03/1996) Publication Summary According to the NASA Astrophysics Data System, I have • 181 research papers published or in press in peer-reviewed journals, with a total h-index of 53 • 21 lead (first or corresponding*) author publications with a total of over 1400 citations • Lead author publications: 1 paper cited at least 200 times (Umetsu* et al. 2014), 6 cited at least 100 times and +1 cited 99 times (Umetsu* et al. -
Study Guide Table of Contents
STUDY GUIDE TABLE OF CONTENTS DIRECTOR’S NOTE 2 THE PLAYWRIGHT 6 HENRIETTA LEAVITT 7 ANNIE JUMP CANNON 9 WILLIAMINA FLEMING 10 EDWARD PICKERING 11 THE LIFE OF A COMPUTER AT HCO 12 STAR SPANKING! 13 TELESCOPES AND THE GREAT REFRACTOR AT HCO 14 GLOSSARY OF ASTRONOMICAL TERMS 15 AN ASTRONOMICAL GLOSSARY 17 THE CAST 18 TIMELINE 20 WHEN I HEARD THE LEARNED ASTRONOMER 21 AUDIENCE ETIQUETTE 22 STUDENT EVALUATION 23 TEACHER EVALUATION 24 2 3 4 5 THE PLAYWRIGHT LAUREN GUNDERSON is the most produced living playwright in America, the winner of the Lanford Wilson Award and the Steinberg/ATCA New Play Award, a finalist for the Susan Smith Blackburn Prize and John Gassner Award for Playwriting, and a recipient of the Mellon Foundation’s 3-Year Residency with Marin Theatre Co. She studied Southern Literature and Drama at Emory University, and Dramatic Writing at NYU’s Tisch School where she was a Reynolds Fellow in Social Entrepreneurship. Her work has been commissioned, produced and developed at companies across the US including the Denver Center (The Book Of Will), South Coast Rep (Emilie, Silent Sky), The Kennedy Center (The Amazing Adventures Of Dr. Wonderful And Her Dog!), the O’Neill Theatre Center, Berkeley Rep, Shotgun Players, TheatreWorks, Crowded Fire, San Francisco Playhouse, Marin Theatre, Synchronicity, Olney Theatre, Geva, and more. Her work is published by Dramatists Play Service (Silent Sky, Bauer), Playscripts (I and You; Exit, Pursued by a Bear; and Toil and Trouble), and Samuel French (Emilie). She is a Playwright in Residence at The Playwrights Foundation, and a proud Dramatists Guild member. -
Observational Cosmology - 30H Course 218.163.109.230 Et Al
Observational cosmology - 30h course 218.163.109.230 et al. (2004–2014) PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Thu, 31 Oct 2013 03:42:03 UTC Contents Articles Observational cosmology 1 Observations: expansion, nucleosynthesis, CMB 5 Redshift 5 Hubble's law 19 Metric expansion of space 29 Big Bang nucleosynthesis 41 Cosmic microwave background 47 Hot big bang model 58 Friedmann equations 58 Friedmann–Lemaître–Robertson–Walker metric 62 Distance measures (cosmology) 68 Observations: up to 10 Gpc/h 71 Observable universe 71 Structure formation 82 Galaxy formation and evolution 88 Quasar 93 Active galactic nucleus 99 Galaxy filament 106 Phenomenological model: LambdaCDM + MOND 111 Lambda-CDM model 111 Inflation (cosmology) 116 Modified Newtonian dynamics 129 Towards a physical model 137 Shape of the universe 137 Inhomogeneous cosmology 143 Back-reaction 144 References Article Sources and Contributors 145 Image Sources, Licenses and Contributors 148 Article Licenses License 150 Observational cosmology 1 Observational cosmology Observational cosmology is the study of the structure, the evolution and the origin of the universe through observation, using instruments such as telescopes and cosmic ray detectors. Early observations The science of physical cosmology as it is practiced today had its subject material defined in the years following the Shapley-Curtis debate when it was determined that the universe had a larger scale than the Milky Way galaxy. This was precipitated by observations that established the size and the dynamics of the cosmos that could be explained by Einstein's General Theory of Relativity.