H E G Y I I B O L
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
The Faint Globular Cluster in the Dwarf Galaxy Andromeda I
Publications of the Astronomical Society of Australia (PASA), Vol. 34, e039, 4 pages (2017). © Astronomical Society of Australia 2017; published by Cambridge University Press. doi:10.1017/pasa.2017.35 The Faint Globular Cluster in the Dwarf Galaxy Andromeda I Nelson Caldwell1, Jay Strader2,7, David J. Sand3,4, Beth Willman5 and Anil C. Seth6 1Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 2Center for Data Intensive and Time Domain Astronomy, Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA 3Department of Physics and Astronomy, Texas Tech University, PO Box 41051, Lubbock, TX 79409, USA 4Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ, 85721, USA 5LSST and Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA 6Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, Utah 84112, USA 7Email: [email protected] (RECEIVED July 7, 2017; ACCEPTED August 10, 2017) Abstract Observations of globular clusters in dwarf galaxies can be used to study a variety of topics, including the structure of dark matter halos and the history of vigorous star formation in low-mass galaxies. We report on the properties of the faint globular cluster (MV ∼−3.4) in the M31 dwarf galaxy Andromeda I. This object adds to the growing population of low-luminosity Local Group galaxies that host single globular clusters. Keywords: galaxies: individual: Andromeda I – globular clusters: general 1 INTRODUCTION a standard cuspy halo were present, the GC would have been very unlikely to have survived to the present day. -
PDF Presentatie Van Frank
13” Frank Hol / Skyheerlen Elfje en Vixen R150S Newton in de jaren ’80 en begin ’90 vooral zon, maan, planeten en Messiers. H.T.S. – vriendin – baan – huis kopen & verbouwen trouwen – kinderen waarneemstop. Vanaf 2006 weer actief waarnemen. Focus op objecten uit de Local Group of Galaxies • 2008: Celestron C14. • 2015: 13” aluminium reisdobson. • 2017-2018-2019: 13” aluminium bino-dobson. Rocherath – SQM 21.2-21.7 13” M31 NGC206 Globulars Stofbanden Stervormings- gebieden … 13” M31 M32 NGC206 Globulars Stofbanden Stervormings- gebieden … NGC206 13” NGC205 M32 M32 is de kern van een NGC 221 galaxy die grotendeels Andromeda opgelokt is door M31. M32 is dan ook net zo X helder als de kern van M31 (met 100 miljoen sterren). Telescoop: ≈ 5.0° x 4.0° verrekijker Locatie: (bijna) overal. De helderste dwerg (vanuit onze breedte) aan de hemel: magnitude 8.1. M110 “Een elliptisch stelsel is NGC 205 dood-saai.” Andromeda Neen, kijk eens hoe mooi het stelsel aan de rand in de X donkere achtergrond verdwijnt. Een watje in de lucht! Telescoop: ≈ 5.0° x 4.0° verrekijker Locatie: (bijna) overal. Een grotere telescoop laat de randen mooi verdwijnen in de omgeving. 30’ x 25’ Burnham’s NGC185 and NGC147 “These two miniature elliptical galaxies appear to be distant Celestial companians of the Great Andromeda Galaxy M31. They are Handbook some 7 degrees north of it in the sky, and are approximately the same distance from us, about 2.2 milion light years.” Start van een lange zoektocht (die nog niet voorbij is). 13” NGC147 Twee elliptische stelsels. & NGC147 is een stuk moeilijker dan NGC185. -
Neutral Hydrogen in Local Group Dwarf Galaxies
Neutral Hydrogen in Local Group Dwarf Galaxies Jana Grcevich Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences COLUMBIA UNIVERSITY 2013 c 2013 Jana Grcevich All rights reserved ABSTRACT Neutral Hydrogen in Local Group Dwarfs Jana Grcevich The gas content of the faintest and lowest mass dwarf galaxies provide means to study the evolution of these unique objects. The evolutionary histories of low mass dwarf galaxies are interesting in their own right, but may also provide insight into fundamental cosmological problems. These include the nature of dark matter, the disagreement be- tween the number of observed Local Group dwarf galaxies and that predicted by ΛCDM, and the discrepancy between the observed census of baryonic matter in the Milky Way’s environment and theoretical predictions. This thesis explores these questions by studying the neutral hydrogen (HI) component of dwarf galaxies. First, limits on the HI mass of the ultra-faint dwarfs are presented, and the HI content of all Local Group dwarf galaxies is examined from an environmental standpoint. We find that those Local Group dwarfs within 270 kpc of a massive host galaxy are deficient in HI as compared to those at larger galactocentric distances. Ram- 4 3 pressure arguments are invoked, which suggest halo densities greater than 2-3 10− cm− × out to distances of at least 70 kpc, values which are consistent with theoretical models and suggest the halo may harbor a large fraction of the host galaxy’s baryons. We also find that accounting for the incompleteness of the dwarf galaxy count, known dwarf galaxies whose gas has been removed could have provided at most 2.1 108 M of HI gas to the Milky Way. -
View Article [19]
ABSTRACT ON THE NATURE OF RADIAL DISPERSION PROFILES FOR DWARF SPHEROIDAL GALAXIES IN THE LOCAL GROUP ACCORDING TO MOND by Matthew James Walentosky Modified Newtonian Dynamics (MOND) has long been the only proposed plausible alternative to dark matter to explain mass discrepancies observed in a wide array of systems. In this thesis, the ability of MOND to ac- curately predict the radial velocity dispersion profile of Milky Way and Andromeda dwarf spheroidal galaxies (dSphs) is investigated. Using a Hermite Individual Timestep Scheme based algorithm, the motion of 10,000 stars is tracked in a Hernquist potential with a MONDian correction applied to the acceleration of each star. The observable properties are compared to present day observations and used to generate radial velocity dis- persion profiles for 5 Milky Way dSphs which can be compared to present day observations to demonstrate the accuracy of the procedure. Our calculations are in good agreement with observations. In addition, predictions are made for the radial velocity dispersion profiles for 17 Andromeda dSphs. The results of this study will show agreement between simulated, observed and calculated bulk dispersion and radial dispersion profiles. These predictions will serve as a test on the validity of MOND to either be verified or discredited by future observations. ON THE NATURE OF RADIAL DISPERSION PROFILES FOR DWARF SPHEROIDAL GALAXIES IN THE LOCAL GROUP ACCORDING TO MOND A Thesis Submitted to the Faculty of Miami University in partial fulfillment of the requirements for the -
Cumulative Bio-Bibliography University of California, Santa Cruz June 2020
Cumulative Bio-Bibliography University of California, Santa Cruz June 2020 Puragra Guhathakurta Astronomer/Professor University of California Observatories/University of California, Santa Cruz ACADEMIC HISTORY 1980–1983 B.Sc. in Physics (Honours), Chemistry, and Mathematics, St. Xavier’s College, University of Calcutta 1984–1985 M.Sc. in Physics, University of Calcutta Science College; transferred to Princeton University after first year of two-year program 1985–1987 M.A. in Astrophysical Sciences, Princeton University 1987–1989 Ph.D. in Astrophysical Sciences, Princeton University POSITIONS HELD 1989–1992 Member, Institute for Advanced Study, School of Natural Sciences 1992–1994 Hubble Fellow, Astrophysical Sciences, Princeton University 1994 Assistant Astronomer, Space Telescope Science Institute (UPD) 1994–1998 Assistant Astronomer/Assistant Professor, UCO/Lick Observatory, University of California, Santa Cruz 1998–2002 Associate Astronomer/Associate Professor, UCO/Lick Observatory, University of California, Santa Cruz 2002–2003 Herzberg Fellow, Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC, Canada 2002– Astronomer/Professor, UCO/Lick Observatory, University of California, Santa Cruz 2009– Faculty Director, Science Internship Program, University of California, Santa Cruz 2012–2018 Adjunct Faculty, Science Department, Castilleja School, Palo Alto, CA 2015 Visiting Faculty, Google Headquarters, Mountain View, CA 2015– Co-founder, Global SPHERE (STEM Programs for High-schoolers Engaging in Research -
Elemental Abundances in the Local Group: Tracing the Formation History of the Great Andromeda Galaxy
Elemental Abundances in the Local Group: Tracing the Formation History of the Great Andromeda Galaxy Thesis by Ivanna A. Escala In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2020 Defended 2020 May 29 ii © 2020 Ivanna A. Escala ORCID: 0000-0002-9933-9551 All rights reserved iii Para mi familia, y para mi iv ACKNOWLEDGEMENTS I would like to thank the many people that have provided me with guidance through- out my thesis, and who have helped me reach the point in my life defined by this achievement. It would have been infinitely more challenging without you all, and I am grateful beyond words. First and foremost, I would like to thank my thesis advisor, Evan N. Kirby, for always making his students a priority. He has been an invaluable mentor, teacher, collaborator, and friend. I am especially thankful that Evan had enough trust in my ability as a competent and independent scientist to be supportive of my extended visit to Princeton. I am privileged to have him as an advisor. I would also like to thank my various mentors throughout my undergraduate edu- cation at the University of California, San Diego, to whom I am indebted: Adam J. Burgasser, who granted me my first opportunity to do research in astronomy, and who believed in me when I most needed it; Dušan Kereš, who helped me develop my skills as a nascent researcher with immeasurable patience and kindness; and Alison Coil, who provided me with much appreciated advice and support on the challenges of navigating a career in astronomy. -
Observer's Handbook 1988
OBSERVER’S HANDBOOK 1988 EDITOR: ROY L. BISHOP THE ROYAL ASTRONOMICAL SOCIETY OF CANADA CONTRIBUTORS AND ADVISORS A l a n H. B a t t e n , Dominion Astrophysical Observatory, 5071 W. Saanich Road, Victoria, BC, Canada V8X 4M6 (The Nearest Stars). L a r r y D. B o g a n , Department of Physics, Acadia University, Wolfville, NS, Canada B0P 1X0 (Configurations of Saturn’s Satellites). T e r e n c e D ic k i n s o n , Yarker, ON, Canada K0K 3N0 (The Planets). D a v id W. D u n h a m , International Occultation Timing Association, P.O. Box 7488, Silver Spring, MD 20907, U.S.A. (Lunar and Planetary Occultations). A l a n D y e r , Edmonton Space Sciences Centre, 11211-142 St., Edmonton, AB, Canada T5M 4A1 (Messier Catalogue, Deep-Sky Objects). F r e d E s p e n a k , Planetary Systems Branch, NASA-Goddard Space Flight Centre, Greenbelt, MD, U.S.A. 20771 (Eclipses and Transits). M a r ie F id l e r , 23 Lyndale D r., Willowdale, ON, Canada M2N 2X9 (Observatories and Planetaria). V ic t o r G a i z a u s k a s , C h r is t ie D o n a l d s o n , T e d K e n n e l l y , Herzberg Institute of Astrophysics, National Research Council, Ottawa, ON, Canada K1A 0R6 (Solar Activity). R o b e r t F. G a r r is o n , David Dunlap Observatory, University of Toronto, Box 360, Richmond Hill, ON, Canada L4C 4Y6 (The Brightest Stars). -
Lacerta I and Cassiopeia III. Two Luminous and Distant Andromeda Satellite Dwarf Galaxies Found in the 3Π Pan-STARRS1 Survey
Lacerta I and Cassiopeia III. Two Luminous and Distant Andromeda Satellite Dwarf Galaxies Found in the 3π Pan-STARRS1 Survey The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Martin, Nicolas F., Colin T. Slater, Edward F. Schlafly, Eric Morganson, Hans-Walter Rix, Eric F. Bell, Benjamin P. M. Laevens, et al. 2013. “Lacerta I and Cassiopeia III. Two Luminous and Distant Andromeda Satellite Dwarf Galaxies Found in the 3π Pan- STARRS1 Survey.” The Astrophysical Journal 772 (1) (June 28): 15. doi:10.1088/0004-637x/772/1/15. Published Version doi:10.1088/0004-637X/772/1/15 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:33462058 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA The Astrophysical Journal, 772:15 (6pp), 2013 July 20 doi:10.1088/0004-637X/772/1/15 C 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A. LACERTA I AND CASSIOPEIA III. TWO LUMINOUS AND DISTANT ANDROMEDA SATELLITE DWARF GALAXIES FOUND IN THE 3π PAN-STARRS1 SURVEY Nicolas F. Martin1,2, Colin T. Slater3, Edward F. Schlafly2, Eric Morganson2, Hans-Walter Rix2, Eric F. Bell3, Benjamin P. M. Laevens1,2, Edouard J. Bernard4, Annette M. N. Ferguson4, Douglas P. Finkbeiner5, William S. Burgett6, Kenneth C. Chambers6, Klaus W. Hodapp6, Nicholas Kaiser6, Rolf-Peter Kudritzki6, Eugene A. -
W.M. Keck Observatory | Annual Report 2010
W.M. Keck Observatory | Annual Report 2010 Headquarters location: Kamuela, Hawai’i, USA A world in whichvision all humankind is inspired and united by the pursuit of knowledge of the infinite Management: variety and richness of the Universe. California Association for Research in Astronomy Partner Institutions: California Institute of Technology (CIT/Caltech), To advance themission frontiers of astronomy and share our University of California (UC), discoveries, inspiring the imagination of all. National Aeronautics and Space Administration (NASA) Observatory Groundbreaking: 1985 Observatory Director: First light Keck I telescope: 1992 Taft E. Armandroff First light Keck II telescope: 1996 Deputy Director: Hilton A. Lewis FY2010 Number of Full Time Employees: 114 COVER: The Keck Telescope dome opens to another evening of Number of Observing Astronomers FY2010: 453 observing the universe. Number of Keck Science Investigations: 405 Number of Refereed Articles FY2010: 283 THIS PAGE: The Keck II Laser aims for space unknown on a cold winter night in November, 2010. The laser causes Fiscal Year begins October 1 sodium atoms in a layer of atmosphere 60 miles above the Federal Identification Number: 95-3972799 Earth to scintillate and form an artificial star. That guide star is used to measure how Earth’s atmosphere is distorting starlight. The distortions are then cancelled out by the Keck Adaptive Optics System. contents Director’s Report 3 Cosmic Visionaries 6 Science Highlights 7 A Day in the Life 12 Finances 18 Fueling Discovery 20 Kudos 22 Science Bibliography 24 2 | W.M. Keck Observatory Annual Report 2010 director’sreport TAFT E. ARMANDROFF Welcome to the W. -
Anomalous Cepheids in the Large Magellanic Cloud Insight Into Their Origin and Connection with the Star Formation History
A&A 540, A102 (2012) Astronomy DOI: 10.1051/0004-6361/201118621 & c ESO 2012 Astrophysics Anomalous Cepheids in the Large Magellanic Cloud Insight into their origin and connection with the star formation history G. Fiorentino1 and M. Monelli2,3 1 INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: [email protected] 2 Instituto de Astrofísica de Canarias, Calle via Lactea s/n, 38205 La Laguna, Tenerife, Spain 3 Departmento de Astrofísica, Universidad de La Laguna, 38200 La Laguna, Tenerife, Spain Received 10 December 2011 / Accepted 13 February 2012 ABSTRACT Context. The properties of variable stars can give independent constraints on the star formation history of the host galaxy, by determining the age and metallicity of the parent population. Aims. We investigate the pulsation properties of 84 Anomalous Cepheids (ACs) detected by the OGLE-III survey in the Large Magellanic Cloud (LMC), in order to understand the formation mechanism and the characteristics of the parent population they came from. Methods. We used an updated theoretical pulsation scenario to derive the mass and the pulsation mode of each AC in the sample. We also used a Kolmogorov-Smirnov test to analyze the spatial distribution of the ACs, in comparison with that of other groups of variable stars, and connect their properties with the star formation history of the LMC. Results. We find that the mean mass of ACs is 1.2 ± 0.2 M. We show that ACs do not follow the same spatial distribution of classical Cepheids. This and the difference in their period-luminosity relations further support the hypothesis that ACs are not the extension to low luminosity of classical Cepheids. -
Exploring Andromeda's Halo with The
No. 8, September 2004 THE ING NEWSLETTER References: Hewett, P., Irwin, M., Skillman, E., Foltz, Warren, S., Hewett, P., Lewis, G., Moller, P., Iovino, A., Shaver, P., 1996, MNRAS, Bolton, A., Burles, S., Schlegel, D., Eisenstein, C., Willis, J., Warren, S., Walton, N., 278, 139. D., Brinkmann, J., 2004, AJ, 127, 1860. 2003, ApJ, 599, L37. Werner, K., Dreizler, S., Wolff, B., 1995, Hewett, P., Warren, S., Willis, J., Bland- A&A, 298, 567. Rauch, T., Kerber, F., Pauli, E.-M., 2004, Hawthorn, J., Lewis, G., 2000, ASP Conf Ser, 195, 94 (astro-ph/9905316). A&A, 417, 647. Paul Hewett ([email protected]) Exploring Andromeda’s Halo with the INT Alan McConnachie1, Annette Ferguson2, Avon Huxor 3, Rodrigo Ibata4, Mike Irwin1, Geraint Lewis 5, Nial Tanvir 3 1: Institute of Astronomy; 2: Max-Planck-Institut für Astrophysik, Garching, Germany; 3: Physical Sciences, University of Hertfordshire; 4: Observatoire de Strasbourg, France; 5: Institute of Astronomy, University of Sydney, Australia. he structure of the outer WFC photometry, which shows the actual length is much greater than regions of galaxies is a key inhomogeneity of this system. Metal- 100 kpc (McConnachie, 2003). The T area in which to look for fossil poor/young stars are coded blue whilst similarity of the colour of this feature remnants of the accreted masses from metal rich/older stars are coded red. with the loop of material at the north which the galaxies that we see today This spectacular image shows in of the survey suggests a connection: are thought to be built (Searle, 1978, amazing detail the wealth of deep follow-up imaging using HST/ACS White, 1978). -
– 1 – Table 1. Basic Information
Table 1. Basic information (1) (2) (3) (4) (5) (6) (7) (8) Galaxy Other names R.A. Dec. Original Publication Comments J2000 J2000 The Milky Way sub-group (in order of distance from the Milky Way) ∗ The Galaxy The Milky Way G S(B)bc 17h45m40.0s -29d00m28s — Position refers to Sgr A Canis Major G ???? 07h12m35.0s -27d40m00s Martin et al. (2004) MW disk substructure? Sagittarius dSph G dSph 18h55m19.5s -30d32m43s Ibata et al. (1994) Tidally disrupting Hydra 1 G ???? 8h55m36.0s 3m36m0.0s Grillmair (2011) Possible disrupting dwarf Tucana III DES J2356-5935 G dSph? 23h56m36.0s -59d36m00s Drlica-Wagner et al. (2015) Cluster? Tidally disrupting? Hydrus 1 G dSph 2h29m33.4s -79m18m32.0s Koposov et al. (2018) Draco II G dSph? 15h52m47.6s +64d33m55s Laevens et al. (2015a) Segue (I) G dSph 10h07m04.0s +16d04m55s Belokurov et al. (2007) Carina 3 G dSph 7h38m31.2s -57m53m59.0s Torrealba et al. (2018) Reticulum 2 DES J0335.6-5403 G dSph? 3h35m42.1s -54d02m57s Bechtol et al. (2015) Cluster? LMC subgroup? –1– Koposov et al. (2015) Cetus II DES J0117-1725 G dSph? 1h17m52.8s -17d25m12s Drlica-Wagner et al. (2015) Part of Sgr stream? (Conn et al. 2018b) Triangulum II Laevens 2 G dSph? 2h13m17.4s +36d10m42s Laevens et al. (2015b) Cluster? Carina 2 G dSph 7h36m25.6s -57m59m57.0s Torrealba et al. (2018) Ursa Major II G dSph 08h51m30.0s +63d07m48s Zucker et al. (2006a) Bootes II G dSph 13h58m00.0s +12d51m00s Walsh et al. (2007) Segue II G dSph 02h19m16.0s +20d10m31s Belokurov et al.