Globular Clusters 1
Total Page：16
File Type：pdf, Size：1020Kb
Load more
Recommended publications
-
Astro-Ph/0006299 (I.E
A&A manuscript no. (will be inserted by hand later) ASTRONOMY Your thesaurus codes are: AND 20(04.01.1; 04.03.1; 08.08.1; 08.16.3; 10.07.2) ASTROPHYSICS Photometric catalog of nearby globular clusters (II). ? A large homogeneous (V;I) color-magnitude diagram data-base. A. Rosenberg1,A.Aparicio2,I.Saviane3 and G. Piotto3 1 Telescopio Nazionale Galileo, vicolo dell’Osservatorio 5, I–35122 Padova, Italy 2 Instituto de Astrofisica de Canarias, Via Lactea, E-38200 La Laguna, Tenerife, Spain 3 Dipartimento di Astronomia, Univ. di Padova, vicolo dell’Osservatorio 5, I–35122 Padova, Italy Abstract. In this paper we present the second and final part northern GGCs by means of 1-m class telescopes, i.e. the 91cm of a large and photometrically homogeneous CCD color- European Southern Observatory (ESO) / Dutch telescope and magnitude diagram (CMD) data base, comprising 52 nearby the 1m Isaac Newton Group (ING) / Jacobus Kapteyn telescope Galactic globular clusters (GGC) imaged in the V and I bands. (JKT). We were able to collect the data for 52 of the 69 known The catalog has been collected using only two telescopes GGCs with (m−M)V ≤ 16:15. Thirty-nine objects have been (one for each hemisphere). The observed clusters represent observed with the Dutch Telescope and the data have been al- 75% of the known Galactic globulars with (m − M)V ≤ ready presented in Paper I. The images and the photometry of 16:15 mag, cover most of the globular cluster metallicity range the remaining 13 GGCs, observed with the JKT are presented (−2:2 ≤ [Fe=H] ≤−0:4), and span Galactocentric distances in this paper. -
Issue 59, Yir 2015
1 Director’s Message 50 Fast Turnaround Program Markus Kissler-Patig Pilot Underway Rachel Mason 3 Probing Time Delays in a Gravitationally Lensed Quasar 54 Base Facility Operations Keren Sharon Gustavo Arriagada 7 GPI Discovers the Most Jupiter-like 58 GRACES: The Beginning of a Exoplanet Ever Directly Detected Scientific Legacy Julien Rameau and Robert De Rosa André-Nicolas Chené 12 First Likely Planets in a Nearby 62 The New Cloud-based Gemini Circumbinary Disk Observatory Archive Valerie Rapson Paul Hirst 16 RCW 41: Dissecting a Very Young 65 Solar Panel System Installed at Cluster with Adaptive Optics Gemini North Benoit Neichel Alexis-Ann Acohido 21 Science Highlights 67 Gemini Legacy Image Releases Nancy A. Levenson Gemini staff contributions 30 On the Horizon 72 Journey Through the Universe Gemini staff contributions Janice Harvey 37 News for Users 75 Viaje al Universo Gemini staff contributions Maria-Antonieta García 46 Adaptive Optics at Gemini South Gaetano Sivo, Vincent Garrel, Rodrigo Carrasco, Markus Hartung, Eduardo Marin, Vanessa Montes, and Chad Trujillo ON THE COVER: GeminiFocus January 2016 A montage featuring GeminiFocus is a quarterly publication a recent Flamingos-2 of the Gemini Observatory image of the galaxy 670 N. A‘ohoku Place, Hilo, Hawai‘i 96720, USA NGC 253’s inner region Phone: (808) 974-2500 Fax: (808) 974-2589 (as discussed in the Science Highlights Online viewing address: section, page 21; with www.gemini.edu/geminifocus an inset showing the Managing Editor: Peter Michaud stellar supercluster Science Editor: Nancy A. Levenson identified as the galaxy’s nucleus) Associate Editor: Stephen James O’Meara and cover pages Designer: Eve Furchgott/Blue Heron Multimedia from each of issue of Any opinions, findings, and conclusions or GeminiFocus in 2015. -
![Arxiv:2012.09981V1 [Astro-Ph.SR] 17 Dec 2020 2 O](https://docslib.b-cdn.net/cover/3257/arxiv-2012-09981v1-astro-ph-sr-17-dec-2020-2-o-73257.webp)
Arxiv:2012.09981V1 [Astro-Ph.SR] 17 Dec 2020 2 O
Contrib. Astron. Obs. Skalnat´ePleso XX, 1 { 20, (2020) DOI: to be assigned later Flare stars in nearby Galactic open clusters based on TESS data Olga Maryeva1;2, Kamil Bicz3, Caiyun Xia4, Martina Baratella5, Patrik Cechvalaˇ 6 and Krisztian Vida7 1 Astronomical Institute of the Czech Academy of Sciences 251 65 Ondˇrejov,The Czech Republic(E-mail: [email protected]) 2 Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, 119234, Moscow, Russia 3 Astronomical Institute, University of Wroc law, Kopernika 11, 51-622 Wroc law, Poland 4 Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotl´aˇrsk´a2, 611 37 Brno, Czech Republic 5 Dipartimento di Fisica e Astronomia Galileo Galilei, Vicolo Osservatorio 3, 35122, Padova, Italy, (E-mail: [email protected]) 6 Department of Astronomy, Physics of the Earth and Meteorology, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynsk´adolina F-2, 842 48 Bratislava, Slovakia 7 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, H-1121 Budapest, Konkoly Thege Mikl´os´ut15-17, Hungary Received: September ??, 2020; Accepted: ????????? ??, 2020 Abstract. The study is devoted to search for flare stars among confirmed members of Galactic open clusters using high-cadence photometry from TESS mission. We analyzed 957 high-cadence light curves of members from 136 open clusters. As a result, 56 flare stars were found, among them 8 hot B-A type ob- jects. Of all flares, 63 % were detected in sample of cool stars (Teff < 5000 K), and 29 % { in stars of spectral type G, while 23 % in K-type stars and ap- proximately 34% of all detected flares are in M-type stars. -
A New Milky Way Halo Star Cluster in the Southern Galactic Sky
The Astrophysical Journal, 767:101 (6pp), 2013 April 20 doi:10.1088/0004-637X/767/2/101 C 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A. A NEW MILKY WAY HALO STAR CLUSTER IN THE SOUTHERN GALACTIC SKY E. Balbinot1,2, B. X. Santiago1,2, L. da Costa2,3,M.A.G.Maia2,3,S.R.Majewski4, D. Nidever5, H. J. Rocha-Pinto2,6, D. Thomas7, R. H. Wechsler8,9, and B. Yanny10 1 Instituto de F´ısica, UFRGS, CP 15051, Porto Alegre, RS 91501-970, Brazil; [email protected] 2 Laboratorio´ Interinstitucional de e-Astronomia–LIneA, Rua Gal. Jose´ Cristino 77, Rio de Janeiro, RJ 20921-400, Brazil 3 Observatorio´ Nacional, Rua Gal. Jose´ Cristino 77, Rio de Janeiro, RJ 22460-040, Brazil 4 Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325, USA 5 Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1042, USA 6 Observatorio´ do Valongo, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 20080-090, Brazil 7 Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, Hampshire PO1 2UP, UK 8 Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA 9 Department of Physics, Stanford University, Stanford, CA 94305, USA 10 Fermi National Laboratory, P.O. Box 500, Batavia, IL 60510-5011, USA Received 2012 October 8; accepted 2013 February 28; published 2013 April 1 ABSTRACT We report on the discovery of a new Milky Way (MW) companion stellar system located at (αJ 2000,δJ 2000) = (22h10m43s.15, 14◦5658.8). -
Broad-Band X-Ray/Γ-Ray Spectra and Binary Parameters of GX 339
Mon. Not. R. Astron. Soc. 000, 1–17 (1998) Printed 5 March 2018 (MN LATEX style file v1.4) Broad-band X-ray/γ-ray spectra and binary parameters of GX 339–4 and their astrophysical implications Andrzej A. Zdziarski1, Juri Poutanen2, Joanna Miko lajewska1, Marek Gierli´nski3,1, Ken Ebisawa4, and W. Neil Johnson5 1N. Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland 2Stockholm Observatory, S-133 36 Saltsj¨obaden, Sweden 3Astronomical Observatory, Jagiellonian University, Orla 171, 30-244 Cracow, Poland 4Laboratory for High Energy Astrophysics, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA 5E. O. Hulburt Center for Space Research, Naval Research Laboratory, Washington, DC 20375, USA Accepted 1998 July 28. Received 1998 January 2 ABSTRACT We present X-ray/γ-ray spectra of the binary GX 339–4 observed in the hard state simultaneously by Ginga and CGRO OSSE during an outburst in 1991 September. The Ginga X-ray spectra are well represented by a power law with a photon spectral index of Γ ≃ 1.75 and a Compton reflection component with a fluorescent Fe Kα line corresponding to a solid angle of an optically-thick, ionized, medium of ∼ 0.4×2π. The OSSE data (> 50 keV) require a sharp high-energy cutoff in the power-law spectrum. The broad-band spectra are very well modelled by repeated Compton scattering in a thermal plasma with an optical depth of τ ∼ 1 and kT ≃ 50 keV. We also study the distance to the system and find it to be ∼> 3 kpc, ruling out earlier determinations of ∼ 1 kpc. -
April 2020 Page 1 of 11
Pretoria Centre ASSA April 2020 Page 1 of 11 NEWSLETTER APRIL 2020 Dear member In the light of the current situation and based upon advice from a virologist at one of the leading pathology laboratories, we regret to have to cancel the March and April viewing evenings and meetings of the Pretoria Centre of ASSA. The situation will be reviewed in time for the May activities and members will be informed of any changes. This decision was not taken lightly, but we believe the health of our members is important and we would not like to be the reason one of our members should fall victim to the virus. We apologize for the inconvenience and trust the skies will be clear wherever you wish to spend time under the stars. Bosman Olivier Chairman TABLE OF CONTENTS Astronomy-related articles on the Internet 2 Astronomy basics: Galaxies 3 Feature of the month: Biggest explosion seen since the Big Bang 3 Astronomy-related images and video clips on the Internet 3 Astronomy basics: Galaxies 3 Observing: A different star cluster - by Magda Streicher 4 NOTICE BOARD 5 Pretoria Centre committee 5 Open Star Clusters with Superimposed Planetary Nebulae: 6 M46/NGC 2438 and NGC 2818/2818A Pretoria Centre ASSA April 2020 Page 2 of 11 Astronomy-related articles on the Internet Is bright Comet ATLAS disintegrating? https://earthsky.org/space/how-to-see-bright- comet-c-2019-y4-atlas?utm_source=EarthSky+News&utm_campaign=11f7198ca6- EMAIL_CAMPAIGN_2018_02_02_COPY_01&utm_medium=email&utm_term=0_c64394 5d79-11f7198ca6-394671529 Meet the giant exoplanet where it rains iron. The temperatures on the day side of giant exoplanet WASP-76b are scorching, high enough for metals to be vapourized. -
Planetary Nebulae
Planetary Nebulae A planetary nebula is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from old red giant stars late in their lives. The term "planetary nebula" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. The mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energizes the shell of nebulous gas around the central star, appearing as a bright colored planetary nebula at several discrete visible wavelengths. Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances. In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. -
NGC 362: Another Globular Cluster with a Split Red Giant Branch⋆⋆⋆⋆⋆⋆
A&A 557, A138 (2013) Astronomy DOI: 10.1051/0004-6361/201321905 & c ESO 2013 Astrophysics NGC 362: another globular cluster with a split red giant branch,, E. Carretta1, A. Bragaglia1, R. G. Gratton2, S. Lucatello2, V. D’Orazi3,4, M. Bellazzini1, G. Catanzaro5, F. Leone6, Y. M om any 2,7, and A. Sollima1 1 INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: [email protected] 2 INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy 3 Dept. of Physics and Astronomy, Macquarie University, Sydney, NSW, 2109 Australia 4 Monash Centre for Astrophysics, Monash University, School of Mathematical Sciences, Building 28, Clayton VIC 3800, Melbourne, Australia 5 INAF – Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy 6 Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 78, 95123 Catania, Italy 7 European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile Received 16 May 2013 / Accepted 11 July 2013 ABSTRACT We obtained FLAMES GIRAFFE+UVES spectra for both first- and second-generation red giant branch (RGB) stars in the globular cluster (GC) NGC 362 and used them to derive abundances of 21 atomic species for a sample of 92 stars. The surveyed elements include proton-capture (O, Na, Mg, Al, Si), α-capture (Ca, Ti), Fe-peak (Sc, V, Mn, Co, Ni, Cu), and neutron-capture elements (Y, Zr, Ba, La, Ce, Nd, Eu, Dy). The analysis is fully consistent with that presented for twenty GCs in previous papers of this series. Stars in NGC 362 seem to be clustered into two discrete groups along the Na-O anti-correlation with a gap at [O/Na] ∼ 0 dex. -
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. -
The Saga of M81: Global View of a Massive Stellar Halo in Formation
Draft version October 27, 2020 Typeset using LATEX twocolumn style in AASTeX63 The Saga of M81: Global View of a Massive Stellar Halo in Formation Adam Smercina ,1, 2 Eric F. Bell ,1 Paul A. Price,3 Colin T. Slater ,2 Richard D'Souza,1, 4 Jeremy Bailin ,5 Roelof S. de Jong ,6 In Sung Jang ,6 Antonela Monachesi ,7, 8 and David Nidever 9, 10 1Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA 2Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580, USA 3Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA 4Vatican Observatory, Specola Vaticana, V-00120, Vatican City State 5Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487-0324, USA 6Leibniz-Institut f¨urAstrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany 7Instituto de Investigaci´onMultidisciplinar en Ciencia y Tecnolog´ıa,Universidad de La Serena, Ra´ulBitr´an1305, La Serena, Chile 8Departamento de F´ısica y Astronom´ıa,Universidad de La Serena, Av. Juan Cisternas 1200 N, La Serena, Chile 9Department of Physics, Montana State University, P.O. Box 173840, Bozeman, MT 59717-3840 10National Optical Astronomy Observatory, 950 North Cherry Ave, Tucson, AZ 85719 (Received 31 October, 2019; Revised 31 August, 2020; Accepted 23 October, 2020) Submitted to The Astrophysical Journal ABSTRACT Recent work has shown that Milky Way-mass galaxies display an incredible range of stellar halo properties, yet the origin of this diversity is unclear. The nearby galaxy M81 | currently interacting with M82 and NGC 3077 | sheds unique light on this problem. -
A Basic Requirement for Studying the Heavens Is Determining Where In
Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short). -
MAY 2014 OT H E D Ebn V E R S E R V E RMAY 2014
THE DENVER OBSERVER MAY 2014 OT h e D eBn v e r S E R V E RMAY 2014 BLOODY BEAUTIFUL!!! LUNAR ECLIPSE SEQUENCE OF APRIL 15, 2014 During mid eclipse, with the moon quite dim, many stars can be seen and photographed near the Calendar moon. In this view, stars a bit fainter than magnitude 15 were recorded. Stars that faint can be seen visually in telescopes with at least eight inches (20 cm) aperture. Added to the mid eclipse image are other views of the moon during the eclipse. The moon images in partial eclipse, flank- 6............................ First quarter moon 14......................................... Full moon ing the copper-colored mid-eclipse, nicely demonstrate the round shadow of the Earth, proving 21............................ Last quarter moon the Earth is round. 24......................... New meteor shower? The bright blue star at lower right is Spica, α (alpha) Virgo. Celestial north is up in this image (at 25 .................... Venus 2̊ South of moon about the 11:30 position on an analog clock). See clarkvision.com for technical details. 29....................................... New moon Image © Roger Clark Inside the Observer MAY SKIES by Dennis Cochran ky & Tel’s annual “Skywatch” issue points out that the inside. In between these local details, we can peek President’s Message....................... 2 S in May, Mars, Arcturus and Vega make a huge arc out at a whole cluster of such galaxies, the Virgo Clus- across the sky. Because of the meanderings of ter. It is mind-boggling to think that each member of Society Directory.......................... 2 Mars, this is not a constant, expected feature of the the cluster is an entire island universe, as we used to Schedule of Events........................