DOCSLIB.ORG

Cartwheel Galaxy - Wikipedia, the Free Encyclopedia Cartwheel Galaxy from Wikipedia, the Free Encyclopedia

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cartwheel Galaxy - Wikipedia, the Free Encyclopedia Cartwheel Galaxy from Wikipedia, the Free Encyclopedia 9/25/2014 Cartwheel Galaxy - Wikipedia, the free encyclopedia Cartwheel Galaxy From Wikipedia, the free encyclopedia The Cartwheel Galaxy (also known as ESO 350-40) is a lenticular galaxy and ring galaxy about 500 million light-years away in the constellation Sculptor. It is an estimated 150,000 light-years across, Cartwheel Galaxy has a mass of about 2.9–4.8 × 109 solar masses, and rotates at 217 km/s.[3] It was discovered by Fritz Zwicky in 1941.[4] Zwicky considered his discovery to be "one of the most complicated structures awaiting its explanation on the basis of stellar dynamics."[4][5] An estimation of the galaxy's span resulted in a conclusion of 150,000 light years, which is slightly larger than the Milky Way.[6] Contents 1 Structures 2 Evolution The Cartwheel Galaxy, false color composite. 3 X-ray sources Observation data (J2000 epoch) 4 References Constellation Sculptor 5 External links Right ascension 00h 37m 41.1s[1] Declination −33° 42′ 59″[1] Structures Redshift 9050 ± 3 km/s[1] Distance 500 Mly (150 Mpc) [2] The Cartwheel galaxy shows non-thermal radio and optical spokes, but they are not the same Type S pec (Ring)[1] spokes.[7] Apparent dimensions (V) 1′.1 × 0″.9[1] Evolution Apparent magnitude (V) 15.2[1] Notable features Ring shape http://en.wikipedia.org/wiki/Cartwheel_Galaxy 1/4 9/25/2014 Cartwheel Galaxy - Wikipedia, the free encyclopedia The galaxy was once a normal spiral galaxy before it apparently underwent a head-on collision with a Other designations smaller companion approximately 200 million years ago (i.e., 200 million years prior to the MCG-06-02-022a,[1] PGC 2248[1] image).[3][8] When the nearby galaxy passed through the Cartwheel Galaxy, the force of the collision caused a powerful shock wave through the galaxy, like a rock being tossed into a sandbed. Moving at See also: Galaxy, List of galaxies high speed, the shock wave swept up gas and dust, creating a starburst around the galaxy's center portion that were unscathed. This explains the bluish ring around the center, brighter portion.[9] It can be seen that the galaxy is beginning to retake the form of a normal spiral galaxy, with arms spreading out from a central core.[8] Alternatively, a model based on the gravitational Jeans instability of both axisymmetric (radial) and nonaxisymmetric (spiral) small-amplitude gravity perturbations allows an association between growing clumps of matter and the gravitationally unstable axisymmetric and nonaxisymmetric waves which take on the appearance of a ring and spokes.[5] X-ray sources The unusual shape of the Cartwheel Galaxy may be due to a collision with a smaller galaxy such as those in the lower left of the image. The most recent star burst (star formation due to compression waves) has lit up the Cartwheel rim, which has a diameter larger than the Milky Way. Star formation via starburst galaxies, such as the Cartwheel Galaxy, results in the formation of large and extremely luminous stars. When massive stars explode as supernovas, they leave behind neutron stars and black holes. Some of these neutron stars and black holes have nearby companion stars, and become powerful sources of X-rays as they pull matter off their companions (also known as ultra and hyperluminous X-ray sources).[10] The brightest X-ray sources are likely black holes with companion stars, and appear as the white dots that lie along the rim of the X-ray image. The A spectacular head-on collision between two Cartwheel contains an exceptionally large number of these black hole binary X-ray sources, because galaxies is seen in this NASA Hubble Space many massive stars formed in the ring. Telescope true-color image of the Cartwheel Galaxy. References 1. ^ a b c d e f g h "NASA/IPAC Extragalactic Database" (http://nedwww.ipac.caltech.edu/). Results for Cartwheel Galaxy. Retrieved 2006-11-25. 2. ^ Moore, Patrick (2000). The Data Book of Astronomy. CRC Press. p. 318. ISBN 0-7503-0620-3. 3. ^ a b Amram P, Mendes de Oliveira C, Boulesteix J, Balkowski C; Mendes De Oliveira; Boulesteix; Balkowski (February 1998). "The Hα kinematic of the Cartwheel galaxy". Astron Astrophys. 330: 881–93. Bibcode:1998A&A...330..881A (http://adsabs.harvard.edu/abs/1998A&A...330..881A). http://en.wikipedia.org/wiki/Cartwheel_Galaxy 2/4 9/25/2014 Cartwheel Galaxy - Wikipedia, the free encyclopedia 4. ^ a b Zwicky F (1941). in Theodore van Karman Anniversary volume Contribution to Applied Mechanics and Related Subjects. Pasadena, California: California Institute of Technology. p. 137. 5. ^ a b Griv E (Oct 2005). "Origin of the Cartwheel Galaxy: disk instability?" (http://www.springerlink.com/content/v103526140211pw4/). Astrophys Space Sci. 299 (4): 371–85. Bibcode:2005Ap&SS.299..371G (http://adsabs.harvard.edu/abs/2005Ap&SS.299..371G). doi:10.1007/s10509-005-3423-5 (http://dx.doi.org/10.1007%2Fs10509-005-3423-5). 6. ^ "Amazing Space- Fast Facts: Cartwheel Galaxy" (http://amazing- space.stsci.edu/resources/fastfacts/cartwheel_galaxy.php.p=Astronomy+basics@,eds,astronomy- basics.php&a=,eds). Amazing Space. 2008. Retrieved 2009-07-03. 7. ^ Mayya YD et al. (2005). "The Discovery of Spiral Arms in the Starburst Galaxy M82". Ap J. 628 (1): L33. arXiv:astro-ph/0506275 (https://arxiv.org/abs/astro-ph/0506275). Bibcode:2005ApJ...628L..33M (http://adsabs.harvard.edu/abs/2005ApJ...628L..33M). doi:10.1086/432644 (http://dx.doi.org/10.1086%2F432644). 8. ^ a b "Cartwheel Galaxy" (http://sites.csn.edu/planetarium/galaxy.html). College of Southern Nevada. Retrieved 2009-07-03. 9. ^ Jane Platt (November 1, 2006). "Cartwheel Galaxy Makes Waves in New NASA Image" (http://www.nasa.gov/mission_pages/galex/galex-20060111.html). NASA. Retrieved 2009-05-15. 10. ^ "The Cartwheel Galaxy - Introduction" (http://chandra.harvard.edu/edu/formal/cartwheel/). Harvard- The Cartwheel galaxy in different light spectra (X- Smithsonian Center for Astrophysics. January 22, 2009. Retrieved July 29, 2013. ray, ultraviolet, visible, and infrared). The image combines data from four different space-based observatories: the Chandra X-ray Observatory External links (purple), the Galaxy Evolution Explorer (ultraviolet/blue), the Hubble Space Telescope Galaxy Evolution Simulation:The Cartwheel Galaxy (visible/green), and the Spitzer Space Telescope (http://burro.cwru.edu/SSAnims/CartwheelFull.mpg) (infrared/red). Image is 160 arcsec across. RA h m s Cartwheel Galaxy at Constellation Guide (http://www.constellation-guide.com/cartwheel- 00 37 41.10 Dec −33° 42′ 58.80″ in Sculptor. Credit: NASA/JPL/Caltech/P.Appleton et al. X-ray: galaxy/) NASA/CXC/A.Wolter & G.Trinchieri et al. Retrieved from "http://en.wikipedia.org/w/index.php?title=Cartwheel_Galaxy&oldid=623583438" Categories: Lenticular galaxies Peculiar galaxies Ring galaxies Sculptor (constellation) PGC objects http://en.wikipedia.org/wiki/Cartwheel_Galaxy 3/4 9/25/2014 Cartwheel Galaxy - Wikipedia, the free encyclopedia This page was last modified on 31 August 2014 at 15:08. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. http://en.wikipedia.org/wiki/Cartwheel_Galaxy 4/4.
Load more

Recommended publications
  • Spiral Galaxies, Elliptical Galaxies, Irregular Galaxies, Dwarf Galaxies, Peculiar/Interacting Galalxies Spiral Galaxies
    Lecture 33: Announcements 1) Pick up graded hwk 5. Good job: Jessica, Jessica, and Elizabeth for a 100% score on hwk 5 and the other 25% of the class with an A. 2) Article and homework 7 were posted on class website on Monday (Apr 18) . Due on Mon Apr 25. 3) Reading Assignment for Quiz Wed Apr 27 Ch 23, Cosmic Perspectives: The Beginning of Time 4) Exam moved to Wed May 4 Lecture 33: Galaxy Formation and Evolution Several topics for galaxy evolution have already been covered in Lectures 2, 3, 4,14,15,16. you should refer to your in-class notes for these topics which include: - Types of galaxies (barred spiral, unbarred spirals, ellipticals, irregulars) - The Local Group of Galaxies, The Virgo and Coma Cluster of galaxies - How images of distant galaxies allow us to look back in time - The Hubble Ultra Deep Field (HUDF) - The Doppler blueshift (Lectures 15-16) - Tracing stars, dust, gas via observations at different wavelengths (Lecture15-16). In next lectures, we will cover - Galaxy Classification. The Hubble Sequence - Mapping the Distance of Galaxies - Mapping the Visible Constituents of Galaxies: Stars, Gas, Dust - Understanding Galaxy Formation and Evolution - Galaxy Interactions: Nearby Galaxies, the Milky Way, Distant Galaxies - Mapping the Dark Matter in Galaxies and in the Universe - The Big Bang - Fates of our Universe and Dark Energy Galaxy Classification Galaxy: Collection of few times (108 to 1012) stars orbiting a common center and bound by gravity. Made of gas, stars, dust, dark matter. There are many types of galaxies and they can be classfiied according to different criteria.
    [Show full text]
  • Star Formation in Ring Galaxies Susan C
    East Tennessee State University Digital Commons @ East Tennessee State University Undergraduate Honors Theses Student Works 5-2016 Star Formation in Ring Galaxies Susan C. Olmsted East Tennessee State Universtiy Follow this and additional works at: https://dc.etsu.edu/honors Part of the Astrophysics and Astronomy Commons, and the Physics Commons Recommended Citation Olmsted, Susan C., "Star Formation in Ring Galaxies" (2016). Undergraduate Honors Theses. Paper 322. https://dc.etsu.edu/honors/ 322 This Honors Thesis - Open Access is brought to you for free and open access by the Student Works at Digital Commons @ East Tennessee State University. It has been accepted for inclusion in Undergraduate Honors Theses by an authorized administrator of Digital Commons @ East Tennessee State University. For more information, please contact [email protected]. Star Formation in Ring Galaxies Susan Olmsted Honors Thesis May 5, 2016 Student: Susan Olmsted: ______________________________________ Mentor: Dr. Beverly Smith: ____________________________________ Reader 1: Dr. Mark Giroux: ____________________________________ Reader 2: Dr. Michele Joyner: __________________________________ 1 Abstract: Ring galaxies are specific types of interacting galaxies in which a smaller galaxy has passed through the center of the disk of another larger galaxy. The intrusion of the smaller galaxy causes the structure of the larger galaxy to compress as the smaller galaxy falls through, and to recoil back after the smaller galaxy passes through, hence the ring-like shape. In our research, we studied the star-forming regions of a sample of ring galaxies and compared to those of other interacting galaxies and normal galaxies. Using UV, optical, and IR archived images in twelve wavelengths from three telescopes, we analyzed samples of star-forming regions in ring and normal spiral galaxies using photometry.
    [Show full text]
  • The X-Ray Luminosity Function of Ultra Luminous X-Ray Sources in Collisional Ring Galaxies
    Draft version June 8, 2018 Typeset using LATEX twocolumn style in AASTeX62 The X-Ray Luminosity Function of Ultra Luminous X-Ray Sources in Collisional Ring Galaxies Anna Wolter,1 Antonella Fruscione,2 and Michela Mapelli3 1INAF-Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy 2Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambdidge, MA, 02138 3INAF-Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, 35122, Padova, Italy (Received March, 7th, 2018; Accepted June, 5th, 2018) Submitted to The Astrophysical Journal ABSTRACT Ring galaxies are fascinating laboratories: a catastrophic impact between two galaxies (one not much smaller than the other) has produced fireworks especially in the larger one, when hit roughly perpendicularly to the plane. We analyze the point sources, produced by the starburst episode following the impact, in the rings of seven galaxies and determine their X-ray luminosity function (XLF). In 39 −1 total we detect 63 sources, of which 50 have luminosity LX ≥ 10 erg s , classifying them as ultra luminous X-ray sources (ULXs). We find that the total XLF is not significantly different from XLFs derived for other kinds of galaxies, with a tendency of having a larger fraction of high X-ray luminosity objects. Both the total number of ULXs and the number of ULXs per unit star formation rate are found in the upper envelope of the more normal galaxies distribution. Further analysis would be needed to address the issue of the nature of the compact component in the binary system. Keywords: galaxies: individual (AM0644-741, Arp143, Arp148) - galaxies: peculiar - galaxies: star formation - X-ray binaries 1.
    [Show full text]
  • NASA Teacher Science Background Q&A
    National Aeronautics and Space Administration Science Teacher’s Background SciGALAXY Q&As NASA / Amazing Space Science Background: Galaxy Q&As 1. What is a galaxy? A galaxy is an enormous collection of a few million to several trillion stars, gas, and dust held together by gravity. Galaxies can be several thousand to hundreds of thousands of light-years across. 2. What is the name of our galaxy? The name of our galaxy is the Milky Way. Our Sun and all of the stars that you see at night belong to the Milky Way. When you go outside in the country on a dark night and look up, you will see a milky, misty-looking band stretching across the sky. When you look at this band, you are looking into the densest parts of the Milky Way — the “disk” and the “bulge.” The Milky Way is a spiral galaxy. (See Q7 for more on spiral galaxies.) 3. Where is Earth in the Milky Way galaxy? Our solar system is in one of the spiral arms of the Milky Way, called the Orion Arm, and is about two-thirds of the way from the center of the galaxy to the edge of the galaxy’s starlight. Earth is the third planet from the Sun in our solar system of eight planets. 4. What is the closest galaxy that is similar to our own galaxy, and how far away is it? The closest spiral galaxy is Andromeda, a galaxy much like our own Milky Way. It is 2. million light-years away from us.
    [Show full text]
  • 6 Supplementary References
    6 6 SUPPLEMENTARY REFERENCES 6 SUPPLEMENTARY REFERENCES 1203 6.1 GENERAL ENCYCLOPEDIAS Cosmology glossary. Western Washington Univ. Planetarium, Bellingham, WA; http://www.wwu.edu/depts/skywise/a101_cosmologyglossary.html. Bilder-Konversationslexikon. 4 vols., Brockhaus, Leipzig (1834). CXC Glossary of astrophysical terms. Chandra X-ray Center (CXC), operated Brockhaus Enzyklopädie. 20 vols., Brockhaus, Wiesbaden (1966–1974). for NASA by Harvard-Smithsonian Center for Astrophysics, Cambridge, Brockhaus-Konversationslexikon. 16 vols., Brockhaus, Leipzig (1892–1897). MA; http://chandra.harvard.edu/resources/glossaryA.html. Chambers’s encyclopaedia (ed. by M.D. LAW). 15 vols., International Learn- Dictionnaire des sciences naturelles (ed. by F.G. CUVIER). Levrault, Stras- ing Systems Corporation Ltd., London (1963). bourg (1816–1826). Columbia encyclopedia. Columbia University Press, New York (6th edn., Dictionary of medieval Latin from British sources (ed. by R.E. LATHAM and 2001–2005); http://www.bartleby.com/65/. D.R. HOWLETT). Oxford University Press, London; vol. 1 (1975) to vol. 6 Collier’s encyclopedia. 24 vols., Macmillan Education Co, New York (1987). (2003). Der Große Herder. 13 vols., Herder, Freiburg (1932–1935). Dictionary of mining, mineral, and related terms [compiled and edited by the Encyclopaedia Britannica. 29 vols. (11th edn., 1911). LoveToKnow™ free U.S. Bureau of Mines, U.S. Dept. of the Interior]. Am. Geol. Inst., Alex- online Encyclopedia; http://www.1911encyclopedia.org/. andria, VA (1997); http://www.maden.hacettepe.edu.tr/dmmrt/index.html. Encyclopaedia Britannica. 24 vols. (1875–1889), 24 vols. (1929), 24 vols. Dictionary of SDI (ed. by H. WALDMAN). Scholarly Resources Imprint, Wil- (1959); 30 vols. (1974–1984); 32 vols. (1985–2002) mington, DE (1988).
    [Show full text]
  • Astronomy Magazine 2020 Index
    Astronomy Magazine 2020 Index SUBJECT A AAVSO (American Association of Variable Star Observers), Spectroscopic Database (AVSpec), 2:15 Abell 21 (Medusa Nebula), 2:56, 59 Abell 85 (galaxy), 4:11 Abell 2384 (galaxy cluster), 9:12 Abell 3574 (galaxy cluster), 6:73 active galactic nuclei (AGNs). See black holes Aerojet Rocketdyne, 9:7 airglow, 6:73 al-Amal spaceprobe, 11:9 Aldebaran (Alpha Tauri) (star), binocular observation of, 1:62 Alnasl (Gamma Sagittarii) (optical double star), 8:68 Alpha Canum Venaticorum (Cor Caroli) (star), 4:66 Alpha Centauri A (star), 7:34–35 Alpha Centauri B (star), 7:34–35 Alpha Centauri (star system), 7:34 Alpha Orionis. See Betelgeuse (Alpha Orionis) Alpha Scorpii (Antares) (star), 7:68, 10:11 Alpha Tauri (Aldebaran) (star), binocular observation of, 1:62 amateur astronomy AAVSO Spectroscopic Database (AVSpec), 2:15 beginner’s guides, 3:66, 12:58 brown dwarfs discovered by citizen scientists, 12:13 discovery and observation of exoplanets, 6:54–57 mindful observation, 11:14 Planetary Society awards, 5:13 satellite tracking, 2:62 women in astronomy clubs, 8:66, 9:64 Amateur Telescope Makers of Boston (ATMoB), 8:66 American Association of Variable Star Observers (AAVSO), Spectroscopic Database (AVSpec), 2:15 Andromeda Galaxy (M31) binocular observations of, 12:60 consumption of dwarf galaxies, 2:11 images of, 3:72, 6:31 satellite galaxies, 11:62 Antares (Alpha Scorpii) (star), 7:68, 10:11 Antennae galaxies (NGC 4038 and NGC 4039), 3:28 Apollo missions commemorative postage stamps, 11:54–55 extravehicular activity
    [Show full text]
  • Morphology and Enhanced Star Formation in a Cartwheel-Like Ring Galaxy F
    Morphology and enhanced star formation in a Cartwheel-like ring galaxy F. Renaud, E. Athanassoula, P. Amram, A. Bosma, F. Bournaud, P. -A. Duc, B. Epinat, J. Fensch, K. Kraljic, V. Perret, et al. To cite this version: F. Renaud, E. Athanassoula, P. Amram, A. Bosma, F. Bournaud, et al.. Morphology and enhanced star formation in a Cartwheel-like ring galaxy. Monthly Notices of the Royal Astronomical Soci- ety, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2018, 473 (1), pp.585-602. 10.1093/mnras/stx2360. hal-02015393 HAL Id: hal-02015393 https://hal.archives-ouvertes.fr/hal-02015393 Submitted on 12 Feb 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. MNRAS 000, 000–000 (0000) Preprint 9 October 2018 Compiled using MNRAS LATEX style file v3.0 Morphology and enhanced star formation in a Cartwheel-like ring galaxy F. Renaud1?, E. Athanassoula2, P. Amram2, A. Bosma2, F. Bournaud3, P.-A. Duc3;4, B. Epinat2, J. Fensch3, K. Kraljic2, V. Perret5, C. Struck6 1 Department of Physics, University of Surrey, Guildford, GU2 7XH, UK 2 Aix Marseille Univ., CNRS, LAM, Laboratoire d’Astrophysique de Marseille, 13388 Marseille, France 3 Laboratoire AIM Paris-Saclay, CEA/IRFU/SAp, Universite´ Paris Diderot, F-91191 Gif-sur-Yvette Cedex, France 4 Observatoire Astronomique de Strasbourg, Universite´ de Strasbourg, CNRS UMR 7550, 11 rue de l’Universite,´ F-67000 Strasbourg, France 5 Institute for Theoretical Physics, University of Zurich,¨ CH-8057 Zurich,¨ Switzerland 6 Department of Physics and Astronomy, Iowa State University, Ames, IA 50011, USA Accepted 2017 September 7.
    [Show full text]
  • The Universe Contents 3 HD 149026 B
    History . 64 Antarctica . 136 Utopia Planitia . 209 Umbriel . 286 Comets . 338 In Popular Culture . 66 Great Barrier Reef . 138 Vastitas Borealis . 210 Oberon . 287 Borrelly . 340 The Amazon Rainforest . 140 Titania . 288 C/1861 G1 Thatcher . 341 Universe Mercury . 68 Ngorongoro Conservation Jupiter . 212 Shepherd Moons . 289 Churyamov- Orientation . 72 Area . 142 Orientation . 216 Gerasimenko . 342 Contents Magnetosphere . 73 Great Wall of China . 144 Atmosphere . .217 Neptune . 290 Hale-Bopp . 343 History . 74 History . 218 Orientation . 294 y Halle . 344 BepiColombo Mission . 76 The Moon . 146 Great Red Spot . 222 Magnetosphere . 295 Hartley 2 . 345 In Popular Culture . 77 Orientation . 150 Ring System . 224 History . 296 ONIS . 346 Caloris Planitia . 79 History . 152 Surface . 225 In Popular Culture . 299 ’Oumuamua . 347 In Popular Culture . 156 Shoemaker-Levy 9 . 348 Foreword . 6 Pantheon Fossae . 80 Clouds . 226 Surface/Atmosphere 301 Raditladi Basin . 81 Apollo 11 . 158 Oceans . 227 s Ring . 302 Swift-Tuttle . 349 Orbital Gateway . 160 Tempel 1 . 350 Introduction to the Rachmaninoff Crater . 82 Magnetosphere . 228 Proteus . 303 Universe . 8 Caloris Montes . 83 Lunar Eclipses . .161 Juno Mission . 230 Triton . 304 Tempel-Tuttle . 351 Scale of the Universe . 10 Sea of Tranquility . 163 Io . 232 Nereid . 306 Wild 2 . 352 Modern Observing Venus . 84 South Pole-Aitken Europa . 234 Other Moons . 308 Crater . 164 Methods . .12 Orientation . 88 Ganymede . 236 Oort Cloud . 353 Copernicus Crater . 165 Today’s Telescopes . 14. Atmosphere . 90 Callisto . 238 Non-Planetary Solar System Montes Apenninus . 166 How to Use This Book 16 History . 91 Objects . 310 Exoplanets . 354 Oceanus Procellarum .167 Naming Conventions . 18 In Popular Culture .
    [Show full text]
  • Books About the Southern Sky
    Books about the Southern Sky Atlas of the Southern Night Sky, Steve Massey and Steve Quirk, 2010, second edition (New Holland Publishers: Australia). Well-illustrated guide to the southern sky, with 100 star charts, photographs by amateur astronomers, and information about telescopes and accessories. The Southern Sky Guide, David Ellyard and Wil Tirion, 2008 (Cambridge University Press: Cambridge). A Walk through the Southern Sky: A Guide to Stars and Constellations and Their Legends, Milton D. Heifetz and Wil Tirion, 2007 (Cambridge University Press: Cambridge). Explorers of the Southern Sky: A History of Astronomy in Australia, R. and R. F. Haynes, D. F. Malin, R. X. McGee, 1996 (Cambridge University Press: Cambridge). Astronomical Objects for Southern Telescopes, E. J. Hartung, Revised and illustrated by David Malin and David Frew, 1995 (Melbourne University Press: Melbourne). An indispensable source of information for observers of southern sky, with vivid descriptions and an extensive bibliography. Astronomy of the Southern Sky, David Ellyard, 1993 (HarperCollins: Pymble, N.S.W.). An introductory-level popular book about observing and making sense of the night sky, especially the southern hemisphere. Under Capricorn: A History of Southern Astronomy, David S. Evans, 1988 (Adam Hilger: Bristol). An excellent history of the development of astronomy in the southern hemisphere, with a good bibliography that names original sources. The Southern Sky: A Practical Guide to Astronomy, David Reidy and Ken Wallace, 1987 (Allen and Unwin: Sydney). A comprehensive history of the discovery and exploration of the southern sky, from the earliest European voyages of discovery to the modern age. Exploring the Southern Sky, S.
    [Show full text]
  • Lecture Notes 18: Galaxies and Galaxy Clusters
    Lecture notes 18: Galaxies and galaxy clusters Immanuel Kant (1724–1824) and Thomas Wright (1711–1786) were among the first to recocnize the possibility that the Milky Way was indeed a stellar disk where the Sun was but one of many. Kant went on to propose that if the Milky Way were limited then perhaps the diffuse “elliptical nebulae” seen in the night sky may also be distant disklike systems similar to our own but seperate. Kant called these objects island universes. Charles Messier (1730–1817) compiled a list of 103 nebulae, many of these Messier Objects are indeed known today to be island universes or seperate galaxies, such as M31 in Andromeda. The nature of the extragalactic nebulae (nor indeed that they were extra- galactic) was not settled until Edwin Hubble (1889–1953) discovered a Cepheid variable in M31 allowing him to calculate the distance to that galaxy as being much greater than the dimensions of the Milky Way. The Shapley – Curtis debate A debate was announced on April 26, 1920 at the Natiol Acadamy of Sciences in Washington D.C. to decide the issue of whether the spiral nebulae resided within the Milky Way or whether they were Kant’s island universes. Harlow Shapley and Heber Curtis were choses to represent opposite points of view. It is interesting to follow the arguments used in the face of poor or incomplete data. The three major questions were: 1. What are the distances to the spirals? Arguments for a small distance: (a) Von Maanen’s measurements of proper motion of rotation in M101 gave a velocity >cif a large distance to M101 was used.
    [Show full text]
  • The Cartwheel Galaxy with XMM-Newton
    A&A 501, 445–453 (2009) Astronomy DOI: 10.1051/0004-6361/200810707 & c ESO 2009 Astrophysics The Cartwheel galaxy with XMM-Newton E. Crivellari, A. Wolter, and G. Trinchieri INAF - Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy e-mail: [email protected] Received 25 July 2008 / Accepted 2 April 2009 ABSTRACT Aims. The extreme environment provided by the Cartwheel ring is analyzed to study its X-ray and optical-UV properties. We compare the Cartwheel with the other members of its group and study the system as a whole in the X-ray band. Methods. We analyze the data of the Cartwheel galaxy obtained with XMM-Newton in two different periods (December 2004 and May 2005). We focus on the X-ray properties of the system and use the OM data to obtain additional information in the optical and UV bands. Each dataset is analyzed separately to study source variability and summed together to study fainter and extended sources. Results. We detect a total of 8 sources associated with the Cartwheel galaxy and three in its vicinity, including G1 and G2, all at 39 −1 LX ≥ 10 erg s , that is the Ultra Luminous X-ray (ULX) source range. The brightest ULX source has been already discussed elsewhere. The spectra of the next three brightest ULX are well fitted by a power-law model with a mean photon index of ∼2. We compare the XMM-Newton and Chandra datasets to study the long-term variability of the sources. At least three sources vary in the 5 months between the two XMM-Newton observations and at least four in the 4-year timeframe between Chandra and XMM-Newton observations.
    [Show full text]
  • Cartwheel Galaxy – a Js9 Activity
    Star Formation and U/HLX’s in the Cartwheel Galaxy – a js9 activity Purpose: To examine the Cartwheel Galaxy in both optical and x-ray bands and determine the sources of the ultra- and hyperluminous x-ray sources. Background: (excerpted from the Hubble News Release, January 10, 1995): “A rare and spectacular head-on collision between two galaxies appears in this NASA Hubble Space Telescope true- color image of the Cartwheel Galaxy, located in the constellation Sculptor. The new details of star birth resolved by Hubble provide an opportunity to study how extremely massive stars are born in large fragmented gas clouds. The striking ring-like feature is a direct result of a smaller intruder galaxy — possibly one of two objects to the right of the ring — that careened through the core of the host galaxy. Like a rock tossed into a lake, the collision sent a ripple of energy into space, plowing gas and dust in front Credit: Kirk Borne (STScI), and NASA of it. Expanding at 200,000 miles per hour, this cosmic tsunami leaves in its wake a firestorm of new star creation. Hubble resolves bright blue knots that are gigantic clusters of newborn stars and immense loops and bubbles blown into space by exploding stars (supernovae) going off like a string of firecrackers. The Cartwheel Galaxy presumably was a normal spiral galaxy like our Milky Way before the collision. This spiral structure is beginning to re-emerge, as seen in the faint arms or spokes between the outer ring and bulls-eye shaped nucleus. The ring contains at least several billion new stars that would not normally have been created in such a short time span.” (excerpted from the Chandra Press Release, January 11, 2006): “When the most massive of these stars explode as supernovas, they leave behind neutron stars and black holes.
    [Show full text]