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Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects
Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Porto Alegre 2017 Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Dissertação elaborada sob orientação do Prof. Dr. Eduardo Luis Damiani Bica, co- orientação do Prof. Dr. Charles José Bon- ato e apresentada ao Instituto de Física da Universidade Federal do Rio Grande do Sul em preenchimento do requisito par- cial para obtenção do título de Mestre em Física. Porto Alegre 2017 Acknowledgements To my parents, who supported me and made this possible, in a time and place where being in a university was just a distant dream. To my dearest friends Elisabeth, Robert, Augusto, and Natália - who so many times helped me go from "I give up" to "I’ll try once more". To my cats Kira, Fen, and Demi - who lazily join me in bed at the end of the day, and make everything worthwhile. "But, first of all, it will be necessary to explain what is our idea of a cluster of stars, and by what means we have obtained it. For an instance, I shall take the phenomenon which presents itself in many clusters: It is that of a number of lucid spots, of equal lustre, scattered over a circular space, in such a manner as to appear gradually more compressed towards the middle; and which compression, in the clusters to which I allude, is generally carried so far, as, by imperceptible degrees, to end in a luminous center, of a resolvable blaze of light." William Herschel, 1789 Abstract We provide a sample of 170 Galactic Globular Clusters (GCs) and analyse its spatial distribution properties. -
Galactic Astronomy with AO: Nearby Star Clusters and Moving Groups
Galactic astronomy with AO: Nearby star clusters and moving groups T. J. Davidgea aDominion Astrophysical Observatory, Victoria, BC Canada ABSTRACT Observations of Galactic star clusters and objects in nearby moving groups recorded with Adaptive Optics (AO) systems on Gemini South are discussed. These include observations of open and globular clusters with the GeMS system, and high Strehl L observations of the moving group member Sirius obtained with NICI. The latter data 2 fail to reveal a brown dwarf companion with a mass ≥ 0.02M in an 18 × 18 arcsec area around Sirius A. Potential future directions for AO studies of nearby star clusters and groups with systems on large telescopes are also presented. Keywords: Adaptive optics, Open clusters: individual (Haffner 16, NGC 3105), Globular Clusters: individual (NGC 1851), stars: individual (Sirius) 1. STAR CLUSTERS AND THE GALAXY Deep surveys of star-forming regions have revealed that stars do not form in isolation, but instead form in clusters or loose groups (e.g. Ref. 25). This is a somewhat surprising result given that most stars in the Galaxy and nearby galaxies are not seen to be in obvious clusters (e.g. Ref. 31). This apparent contradiction can be reconciled if clusters tend to be short-lived. In fact, the pace of cluster destruction has been measured to be roughly an order of magnitude per decade in age (Ref. 17), indicating that the vast majority of clusters have lifespans that are only a modest fraction of the dynamical crossing-time of the Galactic disk. Clusters likely disperse in response to sudden changes in mass driven by supernovae and stellar winds (e.g. -
Two Rings but No Fellowship: Lotr 1 and Its Relation to Planetary Nebulae
Mon. Not. R. Astron. Soc. 000, 1–16 (2013) Printed 17 October 2018 (MN LATEX style file v2.2) Two rings but no fellowship: LoTr 1 and its relation to planetary nebulae possessing barium central stars. A.A. Tyndall1,2⋆, D. Jones2, H.M.J. Boffin2, B. Miszalski3,4, F. Faedi5, M. Lloyd1, J.A. L´opez6, S. Martell7, D. Pollacco5, and M. Santander-Garc´ıa8 1Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, M13 9PL, UK 2European Southern Observatory, Alonso de C´ordova 3107, Casilla 19001, Santiago, Chile 3South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa 4Southern African Large Telescope. PO Box 9, Observatory 7935, South Africa 5Department of Physics, University of Warwick, CV4 7AL, UK 6Instituto de Astronom´ıa, Universidad Nacional Aut´onoma de M´exico, Ensenada, Baja California, C.P. 22800, Mexico 7Australian Astronomical Observatory, North Ryde, 2109 NSW, Australia 8Observatorio Astron´omico National, Madrid, and Centro de Astrobiolog´ıa, CSIC-INTA, Spain Accepted xxxx xxxxxxxx xx. Received xxxx xxxxxxxx xx; in original form xxxx xxxxxxxx xx ABSTRACT LoTr 1 is a planetary nebula thought to contain an intermediate-period binary central star system ( that is, a system with an orbital period, P, between 100 and, say, 1500 days). The system shows the signature of a K-type, rapidly rotating giant, and most likely constitutes an accretion-induced post-mass transfer system similar to other PNe such as LoTr 5, WeBo 1 and A70. Such systems represent rare opportunities to further the investigation into the formation of barium stars and intermediate period post-AGB systems – a formation process still far from being understood. -
September 2020 BRAS Newsletter
A Neowise Comet 2020, photo by Ralf Rohner of Skypointer Photography Monthly Meeting September 14th at 7:00 PM, via Jitsi (Monthly meetings are on 2nd Mondays at Highland Road Park Observatory, temporarily during quarantine at meet.jit.si/BRASMeets). GUEST SPEAKER: NASA Michoud Assembly Facility Director, Robert Champion What's In This Issue? President’s Message Secretary's Summary Business Meeting Minutes Outreach Report Asteroid and Comet News Light Pollution Committee Report Globe at Night Member’s Corner –My Quest For A Dark Place, by Chris Carlton Astro-Photos by BRAS Members Messages from the HRPO REMOTE DISCUSSION Solar Viewing Plus Night Mercurian Elongation Spooky Sensation Great Martian Opposition Observing Notes: Aquila – The Eagle Like this newsletter? See PAST ISSUES online back to 2009 Visit us on Facebook – Baton Rouge Astronomical Society Baton Rouge Astronomical Society Newsletter, Night Visions Page 2 of 27 September 2020 President’s Message Welcome to September. You may have noticed that this newsletter is showing up a little bit later than usual, and it’s for good reason: release of the newsletter will now happen after the monthly business meeting so that we can have a chance to keep everybody up to date on the latest information. Sometimes, this will mean the newsletter shows up a couple of days late. But, the upshot is that you’ll now be able to see what we discussed at the recent business meeting and have time to digest it before our general meeting in case you want to give some feedback. Now that we’re on the new format, business meetings (and the oft neglected Light Pollution Committee Meeting), are going to start being open to all members of the club again by simply joining up in the respective chat rooms the Wednesday before the first Monday of the month—which I encourage people to do, especially if you have some ideas you want to see the club put into action. -
![Arxiv:2012.05245V2 [Astro-Ph.GA] 5 May 2021](https://docslib.b-cdn.net/cover/2914/arxiv-2012-05245v2-astro-ph-ga-5-may-2021-642914.webp)
Arxiv:2012.05245V2 [Astro-Ph.GA] 5 May 2021
Draft version May 6, 2021 Typeset using LATEX twocolumn style in AASTeX63 Charting the Galactic acceleration field I. A search for stellar streams with Gaia DR2 and EDR3 with follow-up from ESPaDOnS and UVES Rodrigo Ibata 1 | Khyati Malhan 2 | Nicolas Martin 1, 3 | Dominique Aubert1 | Benoit Famaey 1 | Paolo Bianchini 1 | Giacomo Monari 1 | Arnaud Siebert 1 | Guillaume F. Thomas 4, 5 | Michele Bellazzini 6 | Piercarlo Bonifacio7 | Elisabetta Caffau7 | Florent Renaud 8 | arXiv:2012.05245v2 [astro-ph.GA] 5 May 2021 1Universit´ede Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550, F-67000 Strasbourg, France 2The Oskar Klein Centre, Department of Physics, Stockholm University, AlbaNova, SE-10691 Stockholm, Sweden 3Max-Planck-Institut f¨urAstronomie, K¨onigstuhl17, D-69117, Heidelberg, Germany 4Instituto de Astrof´ısica de Canarias, E-38205 La Laguna, Tenerife, Spain 5Universidad de La Laguna, Dpto. Astrof´ısica, E-38206 La Laguna, Tenerife, Spain 6INAF - Osservatorio di Astrofisica e Scienza dello Spazio, via Gobetti 93/3, I-40129 Bologna, Italy 7GEPI, Observatoire de Paris, Universit´ePSL, CNRS, 5 Place Jules Janssen, 92190 Meudon, France 8Department of Astronomy and Theoretical Physics, Lund Observatory, Box 43, 221 00 Lund, Sweden Corresponding author: Rodrigo Ibata [email protected] 2 Ibata et al. Submitted to ApJ ABSTRACT We present maps of the stellar streams detected in the Gaia Data Release 2 (DR2) and Early Data Release 3 (EDR3) catalogs using the STREAMFINDER algorithm. We also report the spectroscopic follow-up of the brighter DR2 stream members obtained with the high-resolution CFHT/ESPaDOnS and VLT/UVES spectrographs as well as with the medium-resolution NTT/EFOSC2 spectrograph. -
2012 Annual Progress Report and 2013 Program Plan of the Gemini Observatory
2012 Annual Progress Report and 2013 Program Plan of the Gemini Observatory Association of Universities for Research in Astronomy, Inc. Table of Contents 0 Executive Summary ....................................................................................... 1 1 Introduction and Overview .............................................................................. 5 2 Science Highlights ........................................................................................... 6 2.1 Highest Resolution Optical Images of Pluto from the Ground ...................... 6 2.2 Dynamical Measurements of Extremely Massive Black Holes ...................... 6 2.3 The Best Standard Candle for Cosmology ...................................................... 7 2.4 Beginning to Solve the Cooling Flow Problem ............................................... 8 2.5 A Disappearing Dusty Disk .............................................................................. 9 2.6 Gas Morphology and Kinematics of Sub-Millimeter Galaxies........................ 9 2.7 No Intermediate-Mass Black Hole at the Center of M71 ............................... 10 3 Operations ...................................................................................................... 11 3.1 Gemini Publications and User Relationships ............................................... 11 3.2 Science Operations ........................................................................................ 12 3.2.1 ITAC Software and Queue Filling Results .................................................. -
When Aspherical Cosmic Bubbles Betray a Difficult Marriage
When aspherical cosmic bubbles betray a difcult marriage A study of binary central stars of Planetary Nebulae Henri M.J. Boffin (ESO) Brent Miszalski, D. Frew, A. Moffat, A. Acker, J. Köppen, Q. Parker, R. Corradi, D. Jones, M. Santander-Garcia, P. Rodriguez-Gil, M. Rubio-Diez 2011年10月27日木曜日 Outline The zoo of planetary nebulae Explaining their shape and common envelope evolution The search for binary central stars Morphology affected by binarity? A barium-rich central star discovered Summary 2011年10月27日木曜日 2011年10月27日木曜日 2011年10月27日木曜日 2011年10月27日木曜日 2011年10月27日木曜日 2011年10月27日木曜日 Balick et al./NASA/HST 2011年10月27日木曜日 2011年10月27日木曜日 SN 1987A Eta Car Necklace MyCn18 Menzel 3 2011年10月27日木曜日 V. Icke 2011年10月27日木曜日 Cosmic Ant 2011年10月27日木曜日 Hourglass Nebula MyCn18 2011年10月27日木曜日 HST WFPC2 2011年10月27日木曜日 HST ACS 2011年10月27日木曜日 Causes for density contrasts? Rapid rotation and/or Magnetic fields? 2011年10月27日木曜日 Causes for density contrasts? Rapid rotation and/or Magnetic fields? • Models can reproduce some of the features when no feedback on field is introduced • But require strong fields (not detected) • Need a dynamo to keep the field (Nordhaus et al. 2007) 2011年10月27日木曜日 Causes for density contrasts? Rapid rotation and/or Magnetic fields? Models can reproduce some of the features But require strong fields, not detected Need a dynamo to keep the field 2011年10月27日木曜日 Causes for density contrasts? Rapid rotation and/or Magnetic fields? Binary star? 2011年10月27日木曜日 Causes for density contrasts? Rapid rotation and/or Magnetic fields? Binary star? jets (accretion discs) predicted (common envelope evolution; mass transfer by wind) post-AGB (pre-PNe) 2011年10月27日木曜日 Boffin & Miszalski, 2011 2011年10月27日木曜日 A binary containing 2 WDs! Boffin et al. 2011 2011年10月27日木曜日 Common envelope evolution Credit: STScI 2011年10月27日木曜日 Common envelope evolution Credit: STScI 2011年10月27日木曜日 Boffin et al. -
Spiral Galaxies Like the Milky Way and Andromeda Edge on and Face On
Spiral galaxies like the Milky Way and Andromeda Edge on and face on L of Milky Way ~ few x 10 10 Lsun SDSS image by D. Hogg The Sombrero galaxy 12 kpc 40,000 light years Cartoon of the edge‐on Milky Way galaxy Palomar 5 M5 M13 M15 Images of globular clusters (GCs) (Sloan Digital Sky Survey) Leo I Dwarf Galaxy A galaxy that has 1/10 or fewer the number of stars in a Milky Way sized galaxy Dwarf galaxies Halo of dark maer 250 kpc 800,000 LY Large Magellanic cloud Wei‐Hao Wan, UH image credit (Giant) ellipcal galaxies This type of galaxy is oen found at the centers of galaxy clusters Ellipcal galaxies have relavely less gas, dust, and star formaon than spiral galaxies. They look redder because the ages of their stars are on average older than the stars in a spiral galaxy It is believed that a 2 billion solar mass black hole lives at the center of M87. Electrons accelerang along the strong magnec field near the black hole produce this jet of light and charged parcles. Irregular galaxies forming lots of stars and/or interacng with other galaxies Large Magellanic Cloud – luminosity ~ 1/10 luminosity of the Milky Way The Mice Galaxies Many galaxies live in clusters or groups Hickson Group 87 Image taken at Gemini South Abell Cluster S0740 Image was obtained with the Hubble Space Telescope Map of the Local Group Of Galaxies A dozens of dwarf galaxies and 2 giant spirals (the Milky Way and Andromeda) NGC 205 image credit: www.noao.edu ~ 1/40 Milky Way luminosity Image credit: David W. -
Disk Heating, Galactoseismology, and the Formation of Stellar Halos
galaxies Article Disk Heating, Galactoseismology, and the Formation of Stellar Halos Kathryn V. Johnston 1,*,†, Adrian M. Price-Whelan 2,†, Maria Bergemann 3, Chervin Laporte 1, Ting S. Li 4, Allyson A. Sheffield 5, Steven R. Majewski 6, Rachael S. Beaton 7, Branimir Sesar 3 and Sanjib Sharma 8 1 Department of Astronomy, Columbia University, 550 W 120th st., New York, NY 10027, USA; cfl[email protected] 2 Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA; [email protected] 3 Max Planck Institute for Astronomy, Heidelberg 69117, Germany; [email protected] (M.B.); [email protected] (B.S.) 4 Fermi National Accelerator Laboratory, P. O. Box 500, Batavia, IL 60510, USA; [email protected] 5 Department of Natural Sciences, LaGuardia Community College, City University of New York, 31-10 Thomson Ave., Long Island City, NY 11101, USA; asheffi[email protected] 6 Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904, USA; [email protected] 7 The Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101, USA; [email protected] 8 Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006, Australia; [email protected] * Correspondence: [email protected]; Tel.: +1-212-854-3884 † These authors contributed equally to this work. Academic Editors: Duncan A. Forbes and Ericson D. Lopez Received: 1 July 2017; Accepted: 14 August 2017; Published: 26 August 2017 Abstract: Deep photometric surveys of the Milky Way have revealed diffuse structures encircling our Galaxy far beyond the “classical” limits of the stellar disk. -
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A&A 570, A131 (2014) Astronomy DOI: 10.1051/0004-6361/201424452 & c ESO 2014 Astrophysics Eyes in the sky Interactions between asymptotic giant branch star winds and the interstellar magnetic field?;?? A. J. van Marle1, N. L. J. Cox1, and L. Decin1;2 1 KU Leuven, Institute of Astronomy, Celestijnenlaan 200D, 3001 Leuven, Belgium e-mail: [email protected] 2 Universiteit van Amsterdam, Sterrenkundig Instituut Anton Pannekoek, Science Park 904, 1098 Amsterdam, The Netherlands Received 23 June 2014 / Accepted 6 August 2014 ABSTRACT Context. The extended circumstellar envelopes (CSEs) of evolved low-mass stars display a large variety of morphologies. Understanding the various mechanisms that give rise to these extended structures is important to trace their mass-loss history. Aims. Here, we aim to examine the role of the interstellar magnetic field in shaping the extended morphologies of slow dusty winds of asymptotic giant branch (AGB) stars in an effort to pin-point the origin of so-called eye shaped CSEs of three carbon-rich AGB stars. In addition, we seek to understand if this pre-planetary nebula (PN) shaping can be responsible for asymmetries observed in PNe. Methods. Hydrodynamical simulations are used to study the effect of typical interstellar magnetic fields on the free-expanding spher- ical stellar winds as they sweep up the local interstellar medium (ISM). Results. The simulations show that typical Galactic interstellar magnetic fields of 5 to 10 µG are sufficient to alter the spherical expanding shells of AGB stars to appear as the characteristic eye shape revealed by far-infrared observations. -
Ongoing Surveys for Close Binary Central Stars and Wider Implications
Planetary Nebulae: An Eye to the Future Proceedings IAU Symposium No. 283, 2011 c International Astronomical Union 2012 A. Manchado, L. Stanghellini & D. Sch¨onberner, eds. doi:10.1017/S1743921312010782 Ongoing surveys for close binary central stars and wider implications Brent Miszalski South African Astronomical Observatory and Southern African Large Telescope Foundation, PO Box 9, Observatory, 7935, South Africa email: [email protected] Abstract. Binary central stars have long been invoked to explain the vexing shapes of plane- tary nebulae (PNe) despite there being scant direct evidence to support this hypothesis. Modern large-scale surveys and improved observing strategies have allowed us to significantly boost the number of known close binary central stars and estimate at least 20% of PNe have close binary nuclei that passed through a common-envelope (CE) phase. The larger sample of post-CE neb- ulae appears to have a high proportion of bipolar nebulae, low-ionisation structures (especially in SN1987A-like rings) and polar outflows or jets. These trends are guiding our target selec- tion in ongoing multi-epoch spectroscopic and photometric surveys for new binaries. Multiple new discoveries are being uncovered that further strengthen the connection between post-CE trends and close binaries. These ongoing surveys also have wider implications for understanding CE evolution, low-ionisation structure and jet formation, spectral classification of central stars, asymptotic giant branch (AGB) nucleosynthesis and dust obscuration events in PNe. Keywords. planetary nebulae: general, binaries: general 1. Introduction The shapes of PNe are well known to demonstrate an amazing variety shapes (e.g. Sahai et al. 2011). -
(Also Designated NGC 5904) Is a Globular Cluster in the Constellation Serpens
MESSIER 5 GLOBULAR CLUSTER Messier 5 or M5 (also designated NGC 5904) is a globular cluster in the constellation Serpens. It was discovered by Gottfried Kirch in 1702 when looking for comets. It should not be confused with the much fainter and more distant globular cluster Palomar 5, which is situated nearby in the sky. DISCOVERY AND VISIBILITY M5 is, under extremely good conditions, just visible to the naked eye as a faint "star" near the star 5 Serpentis. Binoculars or small telescopes will identify the object as non-stellar while larger telescopes will show some individual stars, of which the brightest are of apparent magnitude 12.2. Charles Messier also noted it in 1764, but thought it a nebula without any stars associated with it. William Herschel was the first to resolve individual stars in the cluster in 1791, counting roughly 200. (see below for Messier 5 by Hubble Space Telescope details on William Herschel). CHARACTERISTICS Spanning 165 light-years in diameter, M5 is one of the largest known globular clusters. The gravitational sphere of influence of M5, (i.e. the volume of space in which stars are gravitationally bound to it rather than being torn away by the Milky Way's gravitational pull) has a radius of some 200 light-years. At 13 billion years old, M5 is also one of the oldest globular clusters in the Milky Way Galaxy. Its distance is about 24,500 light-years from Earth, and it contains more than 100,000 stars. NOTABLE STARS 105 stars in M5 are known to be variable in brightness, 97 of them belonging to the RR Lyrae type.