DOCSLIB.ORG

22. the Nearest Galaxies - the Local Group

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
22. the Nearest Galaxies - the Local Group 22. The Nearest Galaxies - the Local Group The following table summarizes the basic properties of the nearest galaxies. As of this writing, the Local Group of galaxies consists of about 40 members. More members are likely, however, as increasingly more sensitive surveys probe the sky for nearby faint dwarfs. Therefore, this table should not be regarded as a complete census of our galaxian neighborhood, especially at the faint end. Dynamical masses have been calculated for most of the Local Group systems. These estimates are based on either the gas rotation velocities or the stellar velocity dispersions in the galaxies (see Endnote 16). They range from close to a trillion (1012) solar masses for M31 and the Milky W ay, to less than a few million Suns for the faintest dwarf ellipticals. The corresponding mass-to-light ratios are greatest for the faintest dwarfs, indicating that they harbor the highest proportions of dark matter. Table E6: Selected Galaxies of the Local Group (in order of decreasing luminosity [increasing absolute magnitude, M(B)]) Name Type RA(hr:min) Dec (°: ) Distance m(B) M(B) (1) (2) (3) (4) (light-yrs)(5) (mags)(6) (mags)(7) M31 SbI-II 00:42.73 +41:16.1 2.5 x 106 4.4 -21.6 Galaxy SBbcI-II? 17:45.67 -20:00.5 2.7 x 104 -20.5? M33 ScII-III 01:33.85 +30:39.6 2.7 x 106 6.3 -19.1 LMC SBmIII 05:23.57 -69:45.4 1.6 x 105 0.6 -18.4 SMC ImIV-V 00:52.73 -72:49.7 1.9 x 105 2.8 -17.0 NGC 205 S0/E5p 00:40.37 +41:41.4 2.7 x 106 8.7 -16.0 M32 E2 00:42.70 +40:51.9 2.6 x 106 9.1 -15.8 NGC 3109 SmIV 10:03.12 -26:09.5 4.1 x 106 10.4 -15.2 IC10 Im 00:20.42 +59:17.5 2.7 x 106 12.9 -15.2 NGC 6822 ImIV-V 19:44.93 -14:48.1 1.6 x 106 9.8 -14.8 NGC 147 dE5/dSph 00:33.20 +48:30.5 2.4 x 106 10.3 -14.8 NGC 185 dE3p/dSph 00:38.97 +48:20.2 2.0 x 106 10.0 -14.7 IC 5152 SdmIV-V 22:02.70 -51:17.7 5.2 x 106 11.5 -14.5 IC 1613 ImV 01:04.90 +02:08.0 2.3 x 106 10.2 -14.2 Sextans A ImV 10:11.10 -04:42.5 4.7 x 106 11.7 -14.2 W LM ImIV-V 00:01.97 -15:27.8 3.0 x 106 11.0 -13.9 Sagittarius dIm/dSph 18:55.05 -30:28.7 7.8 x 104 4.1 -12.8 Fornax dE3/dSph 02:39.98 -34:27.0 4.5 x 105 8.2 -12.6 Pegasus dIm/dSph 23:28.57 +14:44.8 3.1 x 106 12.6 -12.3 SagDIG dIm 19:29.98 -17:40.7 3.5 x 106 13.9 -12.1 Leo A dIm 09:59.40 +30:44.7 2.2 x 106 12.9 -11.3 GR8 dIm 12:58.67 +14:13.0 5.2 x 106 14.8 -11.2 And I dE3/dSph 00:45.72 +38:00.4 2.6 x 106 13.5 -11.2 Leo I dE3/dSph 10:08.45 +12:18.5 8.1 x 105 10.9 -11.1 And II dE2/dSph 01:16.45 +33:25.7 1.7 x 106 13.3 -10.5 Sculptor dE3/dSph 01:00.15 -33:42.5 2.6 x 105 8.5 -10.4 LGS 3 dIm/dSph 01:03.88 +21:53.1 2.6 x 106 15.0 -9.9 DDO 210 dIm/dSph 20:46.77 -12:51.0 2.6 x 106 14.9 -9.9 And III dE5/dSph 00:35.28 +36:30.5 2.5 x 106 14.8 -9.7 Leo II dE0/dSph 11:13.48 +22:09.2 6.7 x 105 12.6 -9.0 Tucana dE/dSph 22:41.83 -64:25.2 2.9 x 106 15.7 -8.9 Carina dE4/dSph 06:41.62 -50:58.0 3.3 x 105 11.5 -8.6 Draco dE3/dSph 17:20.32 +57:54.8 2.7 x 105 11.8 -7.8 UrsaMinor dE5/dSph 15:09.18 +67:12.9 2.1 x 105 11.6 -7.6 Notes to table: (1) Name of galaxy. (2) Galaxy classification, based mostly on the Hubble-Sandage system. Dwarf ellipticals are designated —dE,“ while dwarf irregulars are designated dIm. The dwarf spheroidal classification preferred by many investigators of the Local Group is designated —dSph.“ Peculiar morphologies are flagged with a —p.“ (3) Right Ascension (celestial longitude) in units of hours (hrs) and minutes (min), precessed to the 2000.0 epoch. (4) Declination (celestial latitude) in units of degrees (°) and arcminutes ( ), precessed to the 2000.0 epoch. (5) Distance from the Sun in units of light-years, determined mostly from observations of Cepheid and RR Lyrae variable stars. (6) Apparent magnitude at B-band (440 nm wavelength). (7) Absolute magnitude at B-band, based on apparent magnitude m(B) and the distance (see Technical Notes 2 and 3). References for table: Mateo, M. 1998, —Dwarf Galaxies of the Local Group,“ Annual Review of Astronomy and Astrophysics, Vol. 36, p. 435 Sandage, A. and Tammann, G. A. 1981, A Revised Shapley-Ames Catalog of Bright Galaxies, Carnegie Institution of W ashington Publication 635, W ashington, D.C. 23. Nearby Giant Galaxies In the following table, 30 giant spiral (S), lenticular (S0), and elliptical galaxies (E) in the Local Group and other neighboring groups are listed. These galaxies have been selected for their apparent brightness in the sky (with m(B) < 10 mags) and high absolute luminosity (with M(B) < -19 mags and corresponding B-band luminosity exceeding 3 billion Suns [see Endnote 3]). Table E7: Selected Giant Galaxies (in order of increasing distance from the Sun) Name(s) Type RA (hr:min) Size (Å ) vel (km/s) A(B) (mags) (1) Comment Dec (o:Å ) m(B) (mags) Dist. (Mpc) M(B) (mags) (2) (3) (4) (5) (6) Galaxy SBbc(rs)I-II 17:45.67 0.0 -20.5? —MilkyW ay“ -20:00.5 0.008 NGC 224 SbI-II 00:42.73 190 x 60 -10 1.7 (M31) —Andromeda +41:16.1 4.4 0.77* -21.7 NGC 598 Sc(s)II-III 01:33.85 70.8 x 41.7 670 0.6 (M33) —Pinwheel“ +30:39.6 6.3 0.85* -19.0 NGC 55 ,c 00:15.13 32.4 x 5.6 115 0.9 (edge-on) -39:13.2 8.2 2.1 -19.3 NGC 3031 Sb(r)I-II 09:55.57 26.9 x 14.1 124 0.8 (M81) +69:04.1 7.9 3.6* -20.8 NGC 2403 Sc(s)III 07:36.90 21.9 x 12.3 2999 0.6 +65:35.9 8.9 3.2* -19.2 .GC 253 Sc(s) 00:47.60 27.5 x 6.8 504 0.7 (starburst) -25:17.4 8.1 2.8 -19.8 NGC 4736 RSab(rs) 12:50.90 11.2 x 9.1 345 0.5 (M94) +41:07.17 8.9 4.6 -19.9 NGC 6946 Sc(s)II 20:34.85 11.5 x 9.8 336 1.5 +60:09.4 9.7 4.5 -20.1 NGC 5236 SBc(s)II 13:37.00 12.9 x 11.5 275 0.4 (M83) -29:52.0 8.5 4.6 -20.2 NGC 5128 S0+S pec 13:25.48 25.7 x 20.0 251 1.27 (Cen A) (AGN) -43:01.0 7.9 4.6 -21.7 NGC 4826 Sab(s)II 12:56.75 10.0 x 5.4 350 0.7 (M64) +21:41.0 9.4 4.7 -19.7 NGC 4945 Sc 13:05.43 20.0 x 3.8 275 1.3 (edge-on) -49:28.0 9.6 4.7 -20.0 NGC 2903 Sc(s)I-II 09:32.17 12.6 x 6.0 472 0.6 +21:29.9 9.5 6.3 -20.1 NGC 4258 Sb(s)II 12:18.95 18.6 x 7.2 520 0.9 (M106) (AGN) +47:18.4 8.9 6.7 -21.2 NGC 5055 SbcII-III 13:15.83 12.6 x 7.2 550 0.5 (M63) —Sunflower“ +42:01.7 9.3 7.3 -20.5 NGC 5194 Sbc(s)I-II 13:29.88 11.2 x 6.9 541 0.4 (M51) —W hirlpool“ +47:11.9 8.6 7.3 -20.7 NGC 5457 Sc(s)I 14:03.22 28.8 x 26.9 372 0.3 (M101) —Pinwheel“ +54:21.0 8.2 7.4* -21.5 NGC 3627 Sb(s)II.2 11:20.25 9.1 x 4.2 593 0.8 (M66) —Black Eye“ +12:59.1 9.7 8.0 -20.6 NGC 4631 Sc 12:42.08 15.5 x 2.7 606 0.9 (edge-on) +32:32.4 9.8 8.0 -20.6 NGC 3521 Sb(s)II-III 11:05.82 11.0 x 5.1 627 0.8 -00:02.0 9.6 8.7 -20.8 NGC 6744 Sbc(r)II 19:09.77 20.0 x 12.9 663 0.6 -63:51.3 9.2 8.7 -21.1 NGC 1291 SBa 03:17.32 9.8 x 8.1 738 0.2 -41:06.5 9.4 10.0 -20.8 NGC 628 Sc(s)I 01:36.70 10.5 x 9.5 861 0.3 (M74) +15:47.2 9.8 11.5 -20.9 NGC 4594 Sa/Sb 12:40:00 8.7 x 3.5 873 0.9 (M104) —Sombrero“ -11:37.4 9.3 11.3 -21.9 NGC 4472 E1/S0 12:29.78 10.2 x 8.3 822 0.0 (M49) +07:59.8 9.3 14.7 -21.5 NGC 4486 E0 12:30.83 8.3 x 6.6 1136 0.0 (M87) —Virgo A“ +12:23.6 9.6 14.7 -21.2 NGC 4649 S0 12:43.67 7.4 x 6.0 1142 0.0 (M60) +11:33.1 9.8 14.7 -21.0 NGC 1068 Sb(rs)II 02:42.68 7.1 x 6.0 1234 0.5 (M77) (AGN) -00:00.9 9.5 16.7 -22.0 NGC 1316 Sa pec 03:22.70 12.0 x 8.5 1713 0.3 —Fornax A“ -37:12.5 9.6 22.3 -22.4 Notes to table: (1) Name(s) of galaxy in the New General Catalogue (NGC) and Messier (M) listings.
Load more

Recommended publications
  • The HERACLES View of the H -To-HI Ratio in Galaxies
    The HERACLES View of the H2-to-HI Ratio in Galaxies Adam Leroy (NRAO, Hubble Fellow) Fabian Walter, Frank Bigiel, the HERACLES and THINGS teams The Saturday Morning Summary • Star formation rate vs. gas relation on ~kpc scales breaks apart into: A relatively universal CO-SFR relation in nearby disks Systematic environmental scalings in the CO-to-HI ratio • The CO-to-HI ratio is a strong function of radius, total gas, and stellar surface density correlated with ISM properties: dust-to-gas ratio, pressure harder to link to dynamics: gravitational instability, arms • Interpretation: the CO-to-HI ratio traces the efficiency of GMC formation Density and dust can explain much of the observed behavior heracles Fabian Walter Erik Rosolowsky MPIA UBC Frank Bigiel Eva Schinnerer UC Berkeley THINGS plus… MPIA Elias Brinks Antonio Usero Gaelle Dumas U Hertfordshire OAN, Madrid MPIA Erwin de Blok Andreas Schruba Helmut Wiesemeyer U Cape Town IRAM … MPIA Rob Kennicutt Axel Weiss Karl Schuster Cambridge MPIfR IRAM Barry Madore Carsten Kramer Karin Sandstrom Carnegie IRAM MPIA Michele Thornley Daniela Calzetti Kelly Foyle Bucknell UMass MPIA Collaborators The HERA CO-Line Extragalactic Survey First maps Leroy et al. (2009) • IRAM 30m Large Program to map CO J = 2→1 line • Instrument: HERA receiver array operating at 230 GHz • 47 galaxies: dwarfs to starbursts and massive spirals -2 • Very wide-field (~ r25) and sensitive (σ ~ 1-2 Msun pc ) NGS The HI Nearby Galaxy Survey HI Walter et al. (2008), AJ Special Issue (2008) • VLA HI maps of 34 galaxies:
    [Show full text]
  • Linking Dust Emission to Fundamental Properties in Galaxies: the Low-Metallicity Picture?
    A&A 582, A121 (2015) Astronomy DOI: 10.1051/0004-6361/201526067 & c ESO 2015 Astrophysics Linking dust emission to fundamental properties in galaxies: the low-metallicity picture? A. Rémy-Ruyer1;2, S. C. Madden2, F. Galliano2, V. Lebouteiller2, M. Baes3, G. J. Bendo4, A. Boselli5, L. Ciesla6, D. Cormier7, A. Cooray8, L. Cortese9, I. De Looze3;10, V. Doublier-Pritchard11, M. Galametz12, A. P. Jones1, O. Ł. Karczewski13, N. Lu14, and L. Spinoglio15 1 Institut d’Astrophysique Spatiale, CNRS, UMR 8617, 91405 Orsay, France e-mail: [email protected]; [email protected] 2 Laboratoire AIM, CEA/IRFU/Service d’Astrophysique, Université Paris Diderot, Bât. 709, 91191 Gif-sur-Yvette, France 3 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, 9000 Gent, Belgium 4 UK ALMA Regional Centre Node, Jodrell Bank Centre for Astrophysics, School of Physics & Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK 5 Laboratoire d’Astrophysique de Marseille – LAM, Université d’Aix-Marseille & CNRS, UMR 7326, 38 rue F. Joliot-Curie, 13388 Marseille Cedex 13, France 6 Department of Physics, University of Crete, 71003 Heraklion, Greece 7 Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany 8 Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA 9 Centre for Astrophysics & Supercomputing, Swinburne University of Technology, Mail H30, PO Box 218, Hawthorn VIC 3122, Australia 10 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 11 Max-Planck für Extraterrestrische Physik, Giessenbachstr. 1, 85748 Garching-bei-München, Germany 12 European Southern Observatory, Karl-Schwarzschild-Str.
    [Show full text]
  • Big Halpha Kinematical Sample of Barred Spiral Galaxies - I
    BhaBAR: Big Halpha kinematical sample of BARred spiral galaxies - I. Fabry-Perot Observations of 21 galaxies O. Hernandez, C. Carignan, P. Amram, L. Chemin, O. Daigle To cite this version: O. Hernandez, C. Carignan, P. Amram, L. Chemin, O. Daigle. BhaBAR: Big Halpha kinematical sample of BARred spiral galaxies - I. Fabry-Perot Observations of 21 galaxies. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2005, 360 Issue 4, pp.1201. 10.1111/j.1365-2966.2005.09125.x. hal-00014446 HAL Id: hal-00014446 https://hal.archives-ouvertes.fr/hal-00014446 Submitted on 26 Jan 2021 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. Mon. Not. R. Astron. Soc. 360, 1201–1230 (2005) doi:10.1111/j.1365-2966.2005.09125.x BHαBAR: big Hα kinematical sample of barred spiral galaxies – I. Fabry–Perot observations of 21 galaxies O. Hernandez,1,2 † C. Carignan,1 P. Amram,2 L. Chemin1 and O. Daigle1 1Observatoire du mont Megantic,´ LAE, Universitede´ Montreal,´ CP 6128 succ. centre ville, Montreal,´ Quebec,´ Canada H3C 3J7 2Observatoire Astronomique de Marseille Provence et LAM, 2 pl.
    [Show full text]
  • 198 7Apj. . .312L. .11J the Astrophysical Journal, 312:L11-L15
    .11J The Astrophysical Journal, 312:L11-L15,1987 January 1 .312L. © 1987. The American Astronomical Society. All rights reserved. Printed in U.S.A. 7ApJ. 198 INTERSTELLAR DUST IN SHAPLEY-AMES ELLIPTICAL GALAXIES M. Jura and D. W. Kim Department of Astronomy, University of California, Los Angeles AND G. R. Knapp and P. Guhathakurta Princeton University Observatory Received 1986 August 11; accepted 1986 September 30 ABSTRACT We have co-added the IRAS survey data at the positions of the brightest elliptical galaxies in the Revised Shapley-Ames Catalog to increase the sensitivity over that of the IRAS Point Source Catalog. More than half of 7 8 the galaxies (with Bj< \\ mag) are detected at 100 /xm with flux levels indicating, typically, 10 or 10 M0 of cold interstellar matter. The presence of cold gas in ellipticals thus appears to be the rule rather than the exception. Subject headings: galaxies: general — infrared: sources I. INTRODUCTION infrared emission from the elliptical galaxy in the line of sight. The traditional view of early-type galaxies is that they are Our criteria for a real detection are as follows: essentially free of interstellar matter. However, with advances 1. The optical position of the galaxy and the position of the in instrumental sensitivity, it has become possible to observe IRAS source agree to better than V. (The agreement is usually 21 cm emission (Knapp, Turner, and Cunniffe 1985; Wardle much better than T.) and Knapp 1986), optical dust patches (Sadler and Gerhard 2. The flux is at least 3 times the r.m.s. noise.
    [Show full text]
  • Distances to Local Group Galaxies
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Distances to Local Group Galaxies Alistair R. Walker Cerro Tololo Inter-American Observatory, NOAO, Casilla 603, la Serena, Chile Abstract. Distances to galaxies in the Local Group are reviewed. In particular, the distance to the Large Magellanic Cloud is found to be (m M)0 =18:52 0:10, cor- − ± responding to 50; 600 2; 400 pc. The importance of M31 as an analog of the galaxies observed at greater distances± is stressed, while the variety of star formation and chem- ical enrichment histories displayed by Local Group galaxies allows critical evaluation of the calibrations of the various distance indicators in a variety of environments. 1 Introduction The Local Group (hereafter LG) of galaxies has been comprehensively described in the monograph by Sidney van den Berg [1], with update in [2]. The zero- velocity surface has radius of a little more than 1 Mpc, therefore the small sub-group of galaxies consisting of NGC 3109, Antlia, Sextans A and Sextans B lie outside the the LG by this definition, as do galaxies in the direction of the nearby Sculptor and IC342/Maffei groups. Thus the LG consists of two large spirals (the Galaxy and M31) each with their entourage of 11 and 10 smaller galaxies respectively, the dwarf spiral M33, and 13 other galaxies classified as either irregular or spherical. We have here included NGC 147 and NGC 185 as members of the M31 sub-group [60], whether they are actually bound to M31 is not proven.
    [Show full text]
  • HST/WFC3 OBSERVATIONS of an OFF-NUCLEAR SUPERBUBBLE in ARP 220 Kelly E
    The Astrophysical Journal, 810:149 (11pp), 2015 September 10 doi:10.1088/0004-637X/810/2/149 © 2015. The American Astronomical Society. All rights reserved. HST/WFC3 OBSERVATIONS OF AN OFF-NUCLEAR SUPERBUBBLE IN ARP 220 Kelly E. Lockhart1, Lisa J. Kewley2, Jessica R. Lu1, Mark G. Allen3, David Rupke4, Daniela Calzetti5, Richard I. Davies6, Michael A. Dopita2, Hauke Engel6, Timothy M. Heckman7, Claus Leitherer8, and David B. Sanders1 1 Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 2 Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek ACT 2611, Australia 3 Observatoire de Strasbourg, UMR 7550, Strasbourg, F-67000, France 4 Department of Physics, Rhodes College, Memphis, TN 38112, USA 5 Department of Astronomy, University of Massachusetts, Amherst, MA 01003, USA 6 Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, D-85741 Garching, Germany 7 Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA 8 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA Received 2015 March 7; accepted 2015 June 8; published 2015 September 9 ABSTRACT We present a high spatial resolution optical and infrared study of the circumnuclear region in Arp 220, a late-stage galaxy merger. Narrowband imaging using Hubble Space Telescope/WFC3 has resolved the previously observed peak in Hα+[N II] emission into a bubble-shaped feature. This feature measures 1″. 6 in diameter, or 600 pc, and is only 1″ northwest of the western nucleus. The bubble is aligned with the western nucleus and the large-scale outflow axis seen in X-rays.
    [Show full text]
  • Curriculum Vitae Avishay Gal-Yam
    January 27, 2017 Curriculum Vitae Avishay Gal-Yam Personal Name: Avishay Gal-Yam Current address: Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100 Rehovot, Israel. Telephones: home: 972-8-9464749, work: 972-8-9342063, Fax: 972-8-9344477 e-mail: [email protected] Born: March 15, 1970, Israel Family status: Married + 3 Citizenship: Israeli Education 1997-2003: Ph.D., School of Physics and Astronomy, Tel-Aviv University, Israel. Advisor: Prof. Dan Maoz 1994-1996: B.Sc., Magna Cum Laude, in Physics and Mathematics, Tel-Aviv University, Israel. (1989-1993: Military service.) Positions 2013- : Head, Physics Core Facilities Unit, Weizmann Institute of Science, Israel. 2012- : Associate Professor, Weizmann Institute of Science, Israel. 2008- : Head, Kraar Observatory Program, Weizmann Institute of Science, Israel. 2007- : Visiting Associate, California Institute of Technology. 2007-2012: Senior Scientist, Weizmann Institute of Science, Israel. 2006-2007: Postdoctoral Scholar, California Institute of Technology. 2003-2006: Hubble Postdoctoral Fellow, California Institute of Technology. 1996-2003: Physics and Mathematics Research and Teaching Assistant, Tel Aviv University. Honors and Awards 2012: Kimmel Award for Innovative Investigation. 2010: Krill Prize for Excellence in Scientific Research. 2010: Isreali Physical Society (IPS) Prize for a Young Physicist (shared with E. Nakar). 2010: German Federal Ministry of Education and Research (BMBF) ARCHES Prize. 2010: Levinson Physics Prize. 2008: The Peter and Patricia Gruber Award. 2007: European Union IRG Fellow. 2006: “Citt`adi Cefal`u"Prize. 2003: Hubble Fellow. 2002: Tel Aviv U. School of Physics and Astronomy award for outstanding achievements. 2000: Colton Fellow. 2000: Tel Aviv U. School of Physics and Astronomy research and teaching excellence award.
    [Show full text]
  • Long-Period Variables in NGC 147 and NGC 185⋆
    A&A 532, A78 (2011) Astronomy DOI: 10.1051/0004-6361/201116951 & c ESO 2011 Astrophysics Long-period variables in NGC 147 and NGC 185 D. Lorenz1, T. Lebzelter1,W.Nowotny1, J. Telting2, F. Kerschbaum1,H.Olofsson3,4, and H. E. Schwarz 1 University of Vienna, Department of Astronomy, Türkenschanzstrasse 17, 1180 Vienna, Austria e-mail: [email protected] 2 Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain 3 Department of Astronomy, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden 4 Onsala Space Observatory, 43992 Onsala, Sweden Received 24 March 2011 / Accepted 25 May 2011 ABSTRACT Context. Previous studies on the stellar content of the two nearby dwarf galaxies NGC 147 and NGC 185 reveal a rich population of late-type giants in both systems, including a large number of carbon-rich objects. These stars are known to show pronounced photo- metric variability, which can be used for a more detailed characterisation of these highly evolved stars. Owing to their well-studied parameters, these Local Group members are ideal candidates for comparative studies. Aims. Through photometric monitoring, we attempt to provide a catalogue of long-period variables (LPVs), including Mira variables, semi-regular variables, and even irregular variables in NGC 147 and NGC 185. We investigate the light variations and compare the characteristics of these two LPV populations with the results found for other galaxies, such as the LMC. Methods. We carried out time-series photometry in the i-band of the two target galaxies with the Nordic Optical Telescope (NOT), covering a time span of ≈2.5 years.
    [Show full text]
  • The Radio Continuum View of Centaurus Acentaurus A
    TheThe radioradio continuumcontinuum viewview ofof CentaurusCentaurus AA Ron Ekers CSIRO The Many Faces of Centaurus A Sydney, 29 June 2009 Ilana's composite Morganti et al. 1999 9° 10' Burns et al. xx image courtesy Norbert Junkes (MPIfR) WhyWhy CentaurusCentaurus AA isis specialspecial ■ the first extragalactic radio source ■ the brightest source in the Southern Hemisphere ■ the second double lobed source discovered ± after Cygnus A ■ the closest Radio Galaxy ■ the closest AGN ■ the closest SMBH ± VLBI resolution 0.01pc, 100 Rs ■ A spectacular galaxy EvolutionEvolution ofof thethe ModelsModels ■ Radio sources ± Static magnetic field 1960 ± Evolutionary sequence 1970 ± Continuous injection ± Continuous reacceleration ■ Energy source ± Galaxy collisions 1950's ± Nuclear accretions 1960- ± Accretion triggered by collisions 1980- CentaurusCentaurus AA thethe closestclosest AGNAGN ■ Distance 3.4Mpc ■ Next closest comparable AGN M87 17Mpc ! ■ Average distance to a L=1024 W Hz-1 radio galaxies ± 10Mpc ± So we are lucky (or influenced!) ■ Much easier to study at all wavelengths ■ Subtends a large angular size ± Good linear resolution ± Background probes SomeSome RadioRadio GalaxiesGalaxies Name Size Log Log (kpc) Luminosity Energy (ergs sec-1) (ergs) Centaurus A 470 41.7 59.9 Cygnus A 200 45.2 60.6 M87 80 42.0 58.6 M82 1 39.5 55.2 PolarizationPolarization inin CentaurusCentaurus AA Bracewell 1962 ■ April 1962 ■ Parkes 64m just completed ■ Discovered by Bracewell ± Published Cooper and Price ± Visitors Log ± Not a National Facilities yet! ■ Connie
    [Show full text]
  • Dwarfs Walking in a Row the filamentary Nature of the NGC 3109 Association
    A&A 559, L11 (2013) Astronomy DOI: 10.1051/0004-6361/201322744 & c ESO 2013 Astrophysics Letter to the Editor Dwarfs walking in a row The filamentary nature of the NGC 3109 association M. Bellazzini1, T. Oosterloo2;3, F. Fraternali4;3, and G. Beccari5 1 INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: [email protected] 2 Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands 3 Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen, The Netherlands 4 Dipartimento di Fisica e Astronomia - Università degli Studi di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy 5 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei Munchen, Germany Received 24 September 2013 / Accepted 22 October 2013 ABSTRACT We re-consider the association of dwarf galaxies around NGC 3109, whose known members were NGC 3109, Antlia, Sextans A, and Sextans B, based on a new updated list of nearby galaxies and the most recent data. We find that the original members of the NGC 3109 association, together with the recently discovered and adjacent dwarf irregular Leo P, form a very tight and elongated configuration in space. All these galaxies lie within ∼100 kpc of a line that is '1070 kpc long, from one extreme (NGC 3109) to the other (Leo P), and they show a gradient in the Local Group standard of rest velocity with a total amplitude of 43 km s−1 Mpc−1, and a rms scatter of just 16.8 km s−1. It is shown that the reported configuration is exceptional given the known dwarf galaxies in the Local Group and its surroundings.
    [Show full text]
  • Arxiv:2007.04823V1 [Astro-Ph.HE] 9 Jul 2020 Inverse Compton-CMB Models , Although Other Evidence Seems to Be Compatible With
    Title: Resolving acceleration to very high energies along the Jet of Centaurus A Author: The H.E.S.S. Collaboration Correspondence to: [email protected] The full author list with affiliations can be found at the end of this paper Summary: The nearby radio galaxy Centaurus A belongs to a class of Active Galaxies that are very luminous at radio wavelengths. The majority of these galaxies show collimated relativistic outflows known as jets, that extend over hundreds of thousands of parsecs for the most powerful sources. Accretion of matter onto the central super-massive black hole is be- lieved to fuel these jets and power their emission 1, with the radio emission being related to the synchrotron radiation of relativistic electrons in magnetic fields. The origin of the extended X-ray emission seen in the kiloparsec-scale jets from these sources is still a mat- ter of debate, although Centaurus A’s X-ray emission has been suggested to originate in electron synchrotron processes 2–4. The other possible explanation is inverse Compton scat- tering with CMB soft photons 5–7. Synchrotron radiation needs ultra-relativistic electrons (∼ 50 TeV), and given their short cooling times, requires some continuous re-acceleration mechanism to be active 8. Inverse Compton scattering, on the other hand, does not require very energetic electrons, but requires jets that stay highly relativistic on large scales (≥1 Mpc) and that remain well-aligned with the line of sight. Some recent evidence disfavours 9–12 arXiv:2007.04823v1 [astro-ph.HE] 9 Jul 2020 inverse Compton-CMB models , although other evidence seems to be compatible with them 13, 14.
    [Show full text]
  • Astronomy Magazine Special Issue
    γ ι ζ γ δ α κ β κ ε γ β ρ ε ζ υ α φ ψ ω χ α π χ φ γ ω ο ι δ κ α ξ υ λ τ μ β α σ θ ε β σ δ γ ψ λ ω σ η ν θ Aι must-have for all stargazers η δ μ NEW EDITION! ζ λ β ε η κ NGC 6664 NGC 6539 ε τ μ NGC 6712 α υ δ ζ M26 ν NGC 6649 ψ Struve 2325 ζ ξ ATLAS χ α NGC 6604 ξ ο ν ν SCUTUM M16 of the γ SERP β NGC 6605 γ V450 ξ η υ η NGC 6645 M17 φ θ M18 ζ ρ ρ1 π Barnard 92 ο χ σ M25 M24 STARS M23 ν β κ All-in-one introduction ALL NEW MAPS WITH: to the night sky 42,000 more stars (87,000 plotted down to magnitude 8.5) AND 150+ more deep-sky objects (more than 1,200 total) The Eagle Nebula (M16) combines a dark nebula and a star cluster. In 100+ this intense region of star formation, “pillars” form at the boundaries spectacular between hot and cold gas. You’ll find this object on Map 14, a celestial portion of which lies above. photos PLUS: How to observe star clusters, nebulae, and galaxies AS2-CV0610.indd 1 6/10/10 4:17 PM NEW EDITION! AtlAs Tour the night sky of the The staff of Astronomy magazine decided to This atlas presents produce its first star atlas in 2006.
    [Show full text]