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Matt Brorby (U of Iowa) with Philip Kaaret (U of Iowa)
Matt Brorby (U of Iowa) with Philip Kaaret (U of Iowa) Illustration: NASA/CXC/M.Weiss http://chandra.harvard.edu/ Outline • Why study ULX vs metallicity? • Observations: Einstein, ROSAT, etc: N"#$ ,�"#$ ∝ SFR • Recent studies: N"#$, �"#$ /SFR vs Metallicity • Does spectral state depend on metallicity? • How could metallicity affect ULX population? • Outlook for observable properties of ULX-metallicity effects Why? • Knowing the effects of metallicity on the properties of ULX will lead us to understanding more about the early Universe X-rays in the early Universe • Knowing the effects of metallicity on the properties of ULX will lead us to understanding more about the early Universe • Recombination • � ∼ 1000 • Dark Ages • 20 < � < 1000 • Reionization • 6 < � < 20 • Currently • Ionized and warm (IGM) X-rays in the early Universe • X-rays have a large mean free path, ; A.C � (cMpc) ∝ < 5 =>> ?@ (see McQuinn2012; Mesinger+2013; Pacucci+2014) • Allows for more uniform ionization • Most of X-ray energy is deposited as heat (left over energy after ionization) (Shull & van Steenberg 1985) • Would delay the end of reionization due to thermal feedback X-rays in the early Universe (Fialkov, Barkana, & Visbal 2014) • Fiducial model of X-ray emission D • < = 3×10K>� [erg sRS MRS yr] EFG $ ⊙ • � $ = 1 • Reduced X-ray emission S • �$ = S> Soft XRB spectrum • Enhanced X-ray emission Hard XRB spectrum • �$ = 10 • Minimum of curve is beginning of X- ray heating. (Fialkov, Barkana, & Visbal 2014) • Above �AS = 0, reionization begins. X-rays in the early Universe (MiroCha 2014) Gravitational Waves from BH-BH binary LIGO Scientific Collaboration and Virgo Collaboration (2016) • Initial black hole masses of XY XK 36RK M⊙ and 29RK M⊙ XK • Final mass of 62RK M⊙ • “The formation of such massive black holes from stellar evolution requires weak massive-star winds, which are possible in stellar environments with metallicity lower than ≈ 0.5 �⊙.” Abbott et al. -
Moons Phases and Tides
Moon’s Phases and Tides Moon Phases Half of the Moon is always lit up by the sun. As the Moon orbits the Earth, we see different parts of the lighted area. From Earth, the lit portion we see of the moon waxes (grows) and wanes (shrinks). The revolution of the Moon around the Earth makes the Moon look as if it is changing shape in the sky The Moon passes through four major shapes during a cycle that repeats itself every 29.5 days. The phases always follow one another in the same order: New moon Waxing Crescent First quarter Waxing Gibbous Full moon Waning Gibbous Third (last) Quarter Waning Crescent • IF LIT FROM THE RIGHT, IT IS WAXING OR GROWING • IF DARKENING FROM THE RIGHT, IT IS WANING (SHRINKING) Tides • The Moon's gravitational pull on the Earth cause the seas and oceans to rise and fall in an endless cycle of low and high tides. • Much of the Earth's shoreline life depends on the tides. – Crabs, starfish, mussels, barnacles, etc. – Tides caused by the Moon • The Earth's tides are caused by the gravitational pull of the Moon. • The Earth bulges slightly both toward and away from the Moon. -As the Earth rotates daily, the bulges move across the Earth. • The moon pulls strongly on the water on the side of Earth closest to the moon, causing the water to bulge. • It also pulls less strongly on Earth and on the water on the far side of Earth, which results in tides. What causes tides? • Tides are the rise and fall of ocean water. -
College of Arts and Sciences
College of Arts and Sciences ANNUAL REPORT 2004·05 awards won · books published · research findings announced programs implemented · research · teaching · learning new collaborations · development of promising initiatives preparation · dedication · vision ultimate success 1 Message from the Dean . 3 Arts and Sciences By the Numbers . 6 Highlights Education . 8 Research . 12 Public Events . 15 Faculty Achievements . 17 Grants . 20 Financial Resources . 22 Appendices . 23 Editor: Catherine Varga Printing: Lake Erie Graphics 2 MESSAGE FROM THE DEAN I have two stories to tell. The first story is a record of tangible accomplishments: awards won, books published, research findings announced, programs implemented. I trust that you will be as impressed as I am by the array of excellence—on the part of both students and faculty—on display in these pages. The second story is about achievements in the making. I mean by this the ongoing activity of research, teaching, and learning; the forging of new collaborations; and the development of promising initiatives. This is a story of preparation, dedication, and vision, all of which are essential to bringing about our ultimate success. 3 As I look back on 2004-05, several examples of achievement and visionary planning emerge with particular clarity: Faculty and Student Recruitment. The College undertook a record number of faculty searches in 2004-05. By tapping the superb networking capabili- ties developed under the leadership of chief informa- SAGES. Under the College’s leadership, SAGES com- tion officer Thomas Knab, our departments were pleted its third year as a pilot program and prepared able to extend these searches throughout the world, for full implementation in fall 2005. -
History of Astrometry
5 Gaia web site: http://sci.esa.int/Gaia site: web Gaia 6 June 2009 June are emerging about the nature of our Galaxy. Galaxy. our of nature the about emerging are More detailed information can be found on the the on found be can information detailed More technologies developed by creative engineers. creative by developed technologies scientists all over the world, and important conclusions conclusions important and world, the over all scientists of the Universe combined with the most cutting-edge cutting-edge most the with combined Universe the of The results from Hipparcos are being analysed by by analysed being are Hipparcos from results The expression of a widespread curiosity about the nature nature the about curiosity widespread a of expression 118218 stars to a precision of around 1 milliarcsecond. milliarcsecond. 1 around of precision a to stars 118218 trying to answer for many centuries. It is the the is It centuries. many for answer to trying created with the positions, distances and motions of of motions and distances positions, the with created will bring light to questions that astronomers have been been have astronomers that questions to light bring will accuracies obtained from the ground. A catalogue was was catalogue A ground. the from obtained accuracies Gaia represents the dream of many generations as it it as generations many of dream the represents Gaia achieving an improvement of about 100 compared to to compared 100 about of improvement an achieving orbit, the Hipparcos satellite observed the whole sky, sky, whole the observed satellite Hipparcos the orbit, ear Y of them in the solar neighbourhood. -
Introduction to Astronomy from Darkness to Blazing Glory
Introduction to Astronomy From Darkness to Blazing Glory Published by JAS Educational Publications Copyright Pending 2010 JAS Educational Publications All rights reserved. Including the right of reproduction in whole or in part in any form. Second Edition Author: Jeffrey Wright Scott Photographs and Diagrams: Credit NASA, Jet Propulsion Laboratory, USGS, NOAA, Aames Research Center JAS Educational Publications 2601 Oakdale Road, H2 P.O. Box 197 Modesto California 95355 1-888-586-6252 Website: http://.Introastro.com Printing by Minuteman Press, Berkley, California ISBN 978-0-9827200-0-4 1 Introduction to Astronomy From Darkness to Blazing Glory The moon Titan is in the forefront with the moon Tethys behind it. These are two of many of Saturn’s moons Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA 2 Introduction to Astronomy Contents in Brief Chapter 1: Astronomy Basics: Pages 1 – 6 Workbook Pages 1 - 2 Chapter 2: Time: Pages 7 - 10 Workbook Pages 3 - 4 Chapter 3: Solar System Overview: Pages 11 - 14 Workbook Pages 5 - 8 Chapter 4: Our Sun: Pages 15 - 20 Workbook Pages 9 - 16 Chapter 5: The Terrestrial Planets: Page 21 - 39 Workbook Pages 17 - 36 Mercury: Pages 22 - 23 Venus: Pages 24 - 25 Earth: Pages 25 - 34 Mars: Pages 34 - 39 Chapter 6: Outer, Dwarf and Exoplanets Pages: 41-54 Workbook Pages 37 - 48 Jupiter: Pages 41 - 42 Saturn: Pages 42 - 44 Uranus: Pages 44 - 45 Neptune: Pages 45 - 46 Dwarf Planets, Plutoids and Exoplanets: Pages 47 -54 3 Chapter 7: The Moons: Pages: 55 - 66 Workbook Pages 49 - 56 Chapter 8: Rocks and Ice: -
An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies
2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies The National Academies—comprising the National Academy of Sciences, the National Academy of Engineering, the Institute of Medicine, and the National Research Council—work together to enlist the nation’s top scientists, engineers, health professionals, and other experts to study specific issues in science, technology, and medicine that underlie many questions of national importance. The results of their deliberations have inspired some of the nation’s most significant and lasting efforts to improve the health, education, and welfare of the United States and have provided independent advice on issues that affect people’s lives worldwide. To learn more about the Academies’ activities, check the website at www.nationalacademies.org. Copyright 2011 by the National Academy of Sciences. All rights reserved. Printed in the United States of America This study was supported by Contract NNX08AN97G between the National Academy of Sciences and the National Aeronautics and Space Administration, Contract AST-0743899 between the National Academy of Sciences and the National Science Foundation, and Contract DE-FG02-08ER41542 between the National Academy of Sciences and the U.S. Department of Energy. Support for this study was also provided by the Vesto Slipher Fund. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the agencies that provided support for the project. 2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics Committee for a Decadal Survey of Astronomy and Astrophysics ROGER D. -
Exors and the Stellar Birthline Mackenzie S
A&A 600, A133 (2017) Astronomy DOI: 10.1051/0004-6361/201630196 & c ESO 2017 Astrophysics EXors and the stellar birthline Mackenzie S. L. Moody1 and Steven W. Stahler2 1 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA e-mail: [email protected] 2 Astronomy Department, University of California, Berkeley, CA 94720, USA e-mail: [email protected] Received 6 December 2016 / Accepted 23 February 2017 ABSTRACT We assess the evolutionary status of EXors. These low-mass, pre-main-sequence stars repeatedly undergo sharp luminosity increases, each a year or so in duration. We place into the HR diagram all EXors that have documented quiescent luminosities and effective temperatures, and thus determine their masses and ages. Two alternate sets of pre-main-sequence tracks are used, and yield similar results. Roughly half of EXors are embedded objects, i.e., they appear observationally as Class I or flat-spectrum infrared sources. We find that these are relatively young and are located close to the stellar birthline in the HR diagram. Optically visible EXors, on the other hand, are situated well below the birthline. They have ages of several Myr, typical of classical T Tauri stars. Judging from the limited data at hand, we find no evidence that binarity companions trigger EXor eruptions; this issue merits further investigation. We draw several general conclusions. First, repetitive luminosity outbursts do not occur in all pre-main-sequence stars, and are not in themselves a sign of extreme youth. They persist, along with other signs of activity, in a relatively small subset of these objects. -
Impact of Supernovae on Molecular Cloud Evolution Dynamics and Structure
Impact of Supernovae on Molecular Cloud Evolution Dynamics and Structure Bastian K¨ortgen1, Daniel Seifried1, and Robi Banerjee1 1Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany [email protected] Introduction We perform numerical simulations of colliding streams of the WNM, including magnetic fields and self{gravity, to analyse the formation and evolution of molecular clouds subject to supernova feedback from massive stars. Simulation Setup The Supernova Subgrid Model The equations of MHD together with selfgravity and heating and cooling are evolved in time using the The supernova feedback is included into the model by means of a Sedov blast FLASH code [Fryxell et al., 2000]. We use a constant heating rate Γ and the cooling function Λ according to wave solution. We define a volume of radius R = 1 pc centered on the sink [Koyama and Inutsuka, 2000] and [V´azquez-Semadeni et al., 2007]. The table below lists the initial conditions. particle. Within this volume each grid cell is assigned a certain radial veloc- ity vc. This velocity depends on the kinetic energy input. Additionally we U Sink Particle Parameter Value Parameter Value inject thermal energy, which then gives the total amount of injected energy of E = 1051 erg with 65 % thermal and 35 % kinetic energy according to the Flow Mach number Mf 2.0 Alfv´en velocity va [km/s] 5.8 sn Sedov solution. The cell velocity is Turbulent Mach number Ms 0.5 Alfv´enic Mach number Ma 1.96 r vc = Ush Temperature [K] 5000 Plasma Beta β = Pth=PB 1.93 R Number density n cm−3 1.0 Flow Length [pc] 112 Figure 1: Schematic of the where U is the shock velocity, depending on the kinetic energy input. -
Planetarian Index
Planetarian Cumulative Index 1972 – 2008 Vol. 1, #1 through Vol. 37, #3 John Mosley [email protected] The PLANETARIAN (ISSN 0090-3213) is published quarterly by the International Planetarium Society under the auspices of the Publications Committee. ©International Planetarium Society, Inc. From the Compiler I compiled the first edition of this index 25 years ago after a frustrating search to find an article that I knew existed and that I really needed. It was a long search without even annual indices to help. By the time I found it, I had run across a dozen other articles that I’d forgotten about but was glad to see again. It was clear that there are a lot of good articles buried in back issues, but that without some sort of index they’d stay lost. I had recently bought an Apple II computer and was receptive to projects that would let me become more familiar with its word processing program. A cumulative index seemed a reasonable project that would be instructive while not consuming too much time. Hah! I did learn some useful solutions to word-processing problems I hadn’t previously known exist, but it certainly did consume more time than I’d imagined by a factor of a dozen or so. You too have probably reached the point where you’ve invested so much time in a project that it’s psychologically easier to finish it than admit defeat. That’s how the first index came to be, and that’s why I’ve kept it up to date. -
President's Column
AAAS Publication for the members N of the Americanewsletter Astronomical Society September/October 2010, Issue 154 CONTENTS President's Column Debra Meloy Elmegreen, [email protected] 2 Congratulations to all of us in the astronomical community on the completion of the Decadal From the Survey! Two years after the National Research Council organized the Astro2010 Committee to begin its arduous process, the report “New Worlds, New Horizons in Astronomy and Astrophysics” Executive Office is complete. In fact, as I write this article the public roll-out is underway at the Keck Center of the National Academies in Washington, DC. This was truly a community effort, and we should all be proud of it and feel ownership of it. The federal funding agencies and Congress widely view the 3 astronomy decadal process as a model for other disciplines to emulate, and it is extremely important for us to embrace it. Editor, The Astrophysical We are embarking on a period of unprecedented opportunities for astronomical research, thanks to great advances in technology, theory, and observations, and the report presents an exciting Journal Letters and balanced set of science-driven priorities within the framework of realistic budget scenarios. The Astro2010 committee comprised 23 astronomers, selected by the National Academies based on community solicitation of suggested names, who were assisted by panels on different science 4 disciplines, space- and ground-based activities, and study groups on the astronomical infrastructure; these subcommittees had a membership of nearly 200 astronomers from the US astronomical Journals Update community. The Survey report and the panel reports are the culmination of a careful and deliberate consideration of science goals, projects and missions and on the whole astronomical enterprise, based in part on the distillation of over 450 community-submitted white papers, over 100 proposals for 6 research activities, briefings from federal agencies, and 17 Town Halls, along with other federal and international reports. -
Star Formation in the “Gulf of Mexico”
A&A 528, A125 (2011) Astronomy DOI: 10.1051/0004-6361/200912671 & c ESO 2011 Astrophysics Star formation in the “Gulf of Mexico” T. Armond1,, B. Reipurth2,J.Bally3, and C. Aspin2, 1 SOAR Telescope, Casilla 603, La Serena, Chile e-mail: [email protected] 2 Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, Hilo, HI 96720, USA e-mail: [reipurth;caa]@ifa.hawaii.edu 3 Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309, USA e-mail: [email protected] Received 9 June 2009 / Accepted 6 February 2011 ABSTRACT We present an optical/infrared study of the dense molecular cloud, L935, dubbed “The Gulf of Mexico”, which separates the North America and the Pelican nebulae, and we demonstrate that this area is a very active star forming region. A wide-field imaging study with interference filters has revealed 35 new Herbig-Haro objects in the Gulf of Mexico. A grism survey has identified 41 Hα emission- line stars, 30 of them new. A small cluster of partly embedded pre-main sequence stars is located around the known LkHα 185-189 group of stars, which includes the recently erupting FUor HBC 722. Key words. Herbig-Haro objects – stars: formation 1. Introduction In a grism survey of the W80 region, Herbig (1958) detected a population of Hα emission-line stars, LkHα 131–195, mostly The North America nebula (NGC 7000) and the adjacent Pelican T Tauri stars, including the little group LkHα 185 to 189 located nebula (IC 5070), both well known for the characteristic shapes within the dark lane of the Gulf of Mexico, thus demonstrating that have given rise to their names, are part of the single large that low-mass star formation has recently taken place here. -
Astronomy 2008 Index
Astronomy Magazine Article Title Index 10 rising stars of astronomy, 8:60–8:63 1.5 million galaxies revealed, 3:41–3:43 185 million years before the dinosaurs’ demise, did an asteroid nearly end life on Earth?, 4:34–4:39 A Aligned aurorae, 8:27 All about the Veil Nebula, 6:56–6:61 Amateur astronomy’s greatest generation, 8:68–8:71 Amateurs see fireballs from U.S. satellite kill, 7:24 Another Earth, 6:13 Another super-Earth discovered, 9:21 Antares gang, The, 7:18 Antimatter traced, 5:23 Are big-planet systems uncommon?, 10:23 Are super-sized Earths the new frontier?, 11:26–11:31 Are these space rocks from Mercury?, 11:32–11:37 Are we done yet?, 4:14 Are we looking for life in the right places?, 7:28–7:33 Ask the aliens, 3:12 Asteroid sleuths find the dino killer, 1:20 Astro-humiliation, 10:14 Astroimaging over ancient Greece, 12:64–12:69 Astronaut rescue rocket revs up, 11:22 Astronomers spy a giant particle accelerator in the sky, 5:21 Astronomers unearth a star’s death secrets, 10:18 Astronomers witness alien star flip-out, 6:27 Astronomy magazine’s first 35 years, 8:supplement Astronomy’s guide to Go-to telescopes, 10:supplement Auroral storm trigger confirmed, 11:18 B Backstage at Astronomy, 8:76–8:82 Basking in the Sun, 5:16 Biggest planet’s 5 deepest mysteries, The, 1:38–1:43 Binary pulsar test affirms relativity, 10:21 Binocular Telescope snaps first image, 6:21 Black hole sets a record, 2:20 Black holes wind up galaxy arms, 9:19 Brightest starburst galaxy discovered, 12:23 C Calling all space probes, 10:64–10:65 Calling on Cassiopeia, 11:76 Canada to launch new asteroid hunter, 11:19 Canada’s handy robot, 1:24 Cannibal next door, The, 3:38 Capture images of our local star, 4:66–4:67 Cassini confirms Titan lakes, 12:27 Cassini scopes Saturn’s two-toned moon, 1:25 Cassini “tastes” Enceladus’ plumes, 7:26 Cepheus’ fall delights, 10:85 Choose the dome that’s right for you, 5:70–5:71 Clearing the air about seeing vs.