Trans-Pacific Radio Interferometer Observations of Quasi-Stellar Objects
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The Global Jet Structure of the Archetypical Quasar 3C 273
galaxies Article The Global Jet Structure of the Archetypical Quasar 3C 273 Kazunori Akiyama 1,2,3,*, Keiichi Asada 4, Vincent L. Fish 2 ID , Masanori Nakamura 4, Kazuhiro Hada 3 ID , Hiroshi Nagai 3 and Colin J. Lonsdale 2 1 National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA 2 Massachusetts Institute of Technology, Haystack Observatory, 99 Millstone Rd, Westford, MA 01886, USA; vfi[email protected] (V.L.F.); [email protected] (C.J.L.) 3 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; [email protected] (K.H.); [email protected] (H.N.) 4 Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan; [email protected] (K.A.); [email protected] (M.N.) * Correspondence: [email protected] Received: 16 September 2017; Accepted: 8 January 2018; Published: 24 January 2018 Abstract: A key question in the formation of the relativistic jets in active galactic nuclei (AGNs) is the collimation process of their energetic plasma flow launched from the central supermassive black hole (SMBH). Recent observations of nearby low-luminosity radio galaxies exhibit a clear picture of parabolic collimation inside the Bondi accretion radius. On the other hand, little is known of the observational properties of jet collimation in more luminous quasars, where the accretion flow may be significantly different due to much higher accretion rates. In this paper, we present preliminary results of multi-frequency observations of the archetypal quasar 3C 273 with the Very Long Baseline Array (VLBA) at 1.4, 15, and 43 GHz, and Multi-Element Radio Linked Interferometer Network (MERLIN) at 1.6 GHz. -
NASA's Goddard Space Flight Center Laboratory for High Energy
1 NASA’s Goddard Space Flight Center Laboratory for High Energy Astrophysics Greenbelt, Maryland 20771 @S0002-7537~99!00301-7# This report covers the period from July 1, 1997 to June 30, Toshiaki Takeshima, Jane Turner, Ken Watanabe, Laura 1998. Whitlock, and Tahir Yaqoob. This Laboratory’s scientific research is directed toward The following investigators are University of Maryland experimental and theoretical research in the areas of X-ray, Scientists: Drs. Keith Arnaud, Manuel Bautista, Wan Chen, gamma-ray, and cosmic-ray astrophysics. The range of inter- Fred Finkbeiner, Keith Gendreau, Una Hwang, Michael Loe- ests of the scientists includes the Sun and the solar system, wenstein, Greg Madejski, F. Scott Porter, Ian Richardson, stellar objects, binary systems, neutron stars, black holes, the Caleb Scharf, Michael Stark, and Azita Valinia. interstellar medium, normal and active galaxies, galaxy clus- Visiting scientists from other institutions: Drs. Vadim ters, cosmic-ray particles, and the extragalactic background Arefiev ~IKI!, Hilary Cane ~U. Tasmania!, Peter Gonthier radiation. Scientists and engineers in the Laboratory also ~Hope College!, Thomas Hams ~U. Seigen!, Donald Kniffen serve the scientific community, including project support ~Hampden-Sydney College!, Benzion Kozlovsky ~U. Tel such as acting as project scientists and providing technical Aviv!, Richard Kroeger ~NRL!, Hideyo Kunieda ~Nagoya assistance to various space missions. Also at any one time, U.!, Eugene Loh ~U. Utah!, Masaki Mori ~Miyagi U.!, Rob- there are typically between twelve and eighteen graduate stu- ert Nemiroff ~Mich. Tech. U.!, Hagai Netzer ~U. Tel Aviv!, dents involved in Ph.D. research work in this Laboratory. Yasushi Ogasaka ~JSPS!, Lev Titarchuk ~George Mason U.!, Currently these are graduate students from Catholic U., Stan- Alan Tylka ~NRL!, Robert Warwick ~U. -
Star Maps: Where Are the Black Holes?
BLACK HOLE FAQ’s 1. What is a black hole? A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull. There are three kinds of black hole that we have strong evidence for: a. Stellar-mass black holes are the remaining cores of massive stars after they die in a supernova explosion. b. Mid-mass black hole in the centers of dense star clusters Credit : ESA, NASA, and F. Mirabel c. Supermassive black hole are found in the centers of many (and maybe all) galaxies. 2. Can a black hole appear anywhere? No, you need an amount of matter more than 3 times the mass of the Sun before it can collapse to create a black hole. 3. If a star dies, does it always turn into a black hole? No, smaller stars like our Sun end their lives as dense hot stars called white dwarfs. Much more massive stars end their lives in a supernova explosion. The remaining cores of only the most massive stars will form black holes. 4. Will black holes suck up all the matter in the universe? No. A black hole has a very small region around it from which you can't escape, called the “event horizon”. If you (or other matter) cross the horizon, you will be pulled in. But as long as you stay outside of the horizon, you can avoid getting pulled in if you are orbiting fast enough. 5. What happens when a spaceship you are riding in falls into a black hole? Your spaceship, along with you, would be squeezed and stretched until it was torn completely apart as it approached the center of the black hole. -
Arxiv:1705.04776V1 [Astro-Ph.HE] 13 May 2017 Aaua M
White Paper on East Asian Vision for mm/submm VLBI: Toward Black Hole Astrophysics down to Angular Resolution of 1 RS Editors Asada, K.1, Kino, M.2,3, Honma, M.3, Hirota, T.3, Lu, R.-S.4,5, Inoue, M.1, Sohn, B.-W.2,6, Shen, Z.-Q.4, and Ho, P. T. P.1,7 Authors Akiyama, K.3,8, Algaba, J-C.2, An, T.4, Bower, G.1, Byun, D-Y.2, Dodson, R.9, Doi, A.10, Edwards, P.G.11, Fujisawa, K.12, Gu, M-F.4, Hada, K.3, Hagiwara, Y.13, Jaroenjittichai, P.15, Jung, T.2,6, Kawashima, T.3, Koyama, S.1,5, Lee, S-S.2, Matsushita, S.1, Nagai, H.3, Nakamura, M.1, Niinuma, K.12, Phillips, C.11, Park, J-H.15, Pu, H-Y.1, Ro, H-W.2,6, Stevens, J.11, Trippe, S.15, Wajima, K.2, Zhao, G-Y.2 1 Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan 2 Korea Astronomy and Space Science Institute, Daedukudae-ro 776, Yuseong-gu, Daejeon 34055, Republic of Korea 3 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan 4 Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China 5 Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, D-53121 Bonn, Germany 6 University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea 7 East Asian Observatory, 660 N. -
The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope M
The Astrophysical Journal, 810:14 (34pp), 2015 September 1 doi:10.1088/0004-637X/810/1/14 © 2015. The American Astronomical Society. All rights reserved. THE THIRD CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE M. Ackermann1, M. Ajello2, W. B. Atwood3, L. Baldini4, J. Ballet5, G. Barbiellini6,7, D. Bastieri8,9, J. Becerra Gonzalez10,11, R. Bellazzini12, E. Bissaldi13, R. D. Blandford14, E. D. Bloom14, R. Bonino15,16, E. Bottacini14, T. J. Brandt10, J. Bregeon17, R. J. Britto18, P. Bruel19, R. Buehler1, S. Buson8,9, G. A. Caliandro14,20, R. A. Cameron14, M. Caragiulo13, P. A. Caraveo21, B. Carpenter10,22, J. M. Casandjian5, E. Cavazzuti23, C. Cecchi24,25, E. Charles14, A. Chekhtman26, C. C. Cheung27, J. Chiang14, G. Chiaro9, S. Ciprini23,24,28, R. Claus14, J. Cohen-Tanugi17, L. R. Cominsky29, J. Conrad30,31,32,70, S. Cutini23,24,28,R.D’Abrusco33,F.D’Ammando34,35, A. de Angelis36, R. Desiante6,37, S. W. Digel14, L. Di Venere38, P. S. Drell14, C. Favuzzi13,38, S. J. Fegan19, E. C. Ferrara10, J. Finke27, W. B. Focke14, A. Franckowiak14, L. Fuhrmann39, Y. Fukazawa40, A. K. Furniss14, P. Fusco13,38, F. Gargano13, D. Gasparrini23,24,28, N. Giglietto13,38, P. Giommi23, F. Giordano13,38, M. Giroletti34, T. Glanzman14, G. Godfrey14, I. A. Grenier5, J. E. Grove27, S. Guiriec10,2,71, J. W. Hewitt41,42, A. B. Hill14,43,68, D. Horan19, R. Itoh40, G. Jóhannesson44, A. S. Johnson14, W. N. Johnson27, J. Kataoka45,T.Kawano40, F. Krauss46, M. Kuss12, G. La Mura9,47, S. Larsson30,31,48, L. -
Virgo the Virgin
Virgo the Virgin Virgo is one of the constellations of the zodiac, the group tion Virgo itself. There is also the connection here with of 12 constellations that lies on the ecliptic plane defined “The Scales of Justice” and the sign Libra which lies next by the planets orbital orientation around the Sun. Virgo is to Virgo in the Zodiac. The study of astronomy had a one of the original 48 constellations charted by Ptolemy. practical “time keeping” aspect in the cultures of ancient It is the largest constellation of the Zodiac and the sec- history and as the stars of Virgo appeared before sunrise ond - largest constellation after Hydra. Virgo is bordered by late in the northern summer, many cultures linked this the constellations of Bootes, Coma Berenices, Leo, Crater, asterism with crops, harvest and fecundity. Corvus, Hydra, Libra and Serpens Caput. The constella- tion of Virgo is highly populated with galaxies and there Virgo is usually depicted with angel - like wings, with an are several galaxy clusters located within its boundaries, ear of wheat in her left hand, marked by the bright star each of which is home to hundreds or even thousands of Spica, which is Latin for “ear of grain”, and a tall blade of galaxies. The accepted abbreviation when enumerating grass, or a palm frond, in her right hand. Spica will be objects within the constellation is Vir, the genitive form is important for us in navigating Virgo in the modern night Virginis and meteor showers that appear to originate from sky. Spica was most likely the star that helped the Greek Virgo are called Virginids. -
Counting Gamma Rays in the Directions of Galaxy Clusters
A&A 567, A93 (2014) Astronomy DOI: 10.1051/0004-6361/201322454 & c ESO 2014 Astrophysics Counting gamma rays in the directions of galaxy clusters D. A. Prokhorov1 and E. M. Churazov1,2 1 Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany e-mail: [email protected] 2 Space Research Institute (IKI), Profsouznaya 84/32, 117997 Moscow, Russia Received 6 August 2013 / Accepted 19 May 2014 ABSTRACT Emission from active galactic nuclei (AGNs) and from neutral pion decay are the two most natural mechanisms that could establish a galaxy cluster as a source of gamma rays in the GeV regime. We revisit this problem by using 52.5 months of Fermi-LAT data above 10 GeV and stacking 55 clusters from the HIFLUCGS sample of the X-ray brightest clusters. The choice of >10 GeV photons is optimal from the point of view of angular resolution, while the sample selection optimizes the chances of detecting signatures of neutral pion decay, arising from hadronic interactions of relativistic protons with an intracluster medium, which scale with the X-ray flux. In the stacked data we detected a signal for the central 0.25 deg circle at the level of 4.3σ. Evidence for a spatial extent of the signal is marginal. A subsample of cool-core clusters has a higher count rate of 1.9 ± 0.3 per cluster compared to the subsample of non-cool core clusters at 1.3 ± 0.2. Several independent arguments suggest that the contribution of AGNs to the observed signal is substantial, if not dominant. -
'-. 5 36 B6 19650268
-- '-. 5 36_B6 _ rr_nm O/ITEE I_ATUREOF THE QUASI-S_ OBJECTS F. HOYLE , University of Cambridge- C_m_ridge,Eng!and and G. R. BURBIDGE :University of California at San Diego La Jolla, California ) 19650268 1965026885-002 ON _ NA_NJEE OF THE QUASI-STELLAR OBJECTS F. HOYLE Uni,_ersity of Cambridge Cambridge, England and G. R. BURBIDGE University of California at San Diego - La Jolla, California Received July 1965 1985028885-003 ABST_ACT In this paper we discuss the origin of the quasi-stellar objects from , two different points of view: (i) that they are objects al;cosmological distances as has been commonly supposed, and (ii) that they are local obje:ts situated at distance _ 1 - l0 Mpc. In the introductory section the optical properties of the quasi-stellar objects ar_:compared with the optical properties of galaxies associated with strong radio courses and Syefert nuclei from both points of view. Section II is devoted to a d.Lscussion of (i) and on this basis it is argue_ that they are most probably the nuclei of galaxies which have reached a high density phase at which time the formation of me_sive objects and their subsequent evolution has occurred. Apart from the suggestion of Terrell little atr.entionhas been paid until now to the possibility that they are local objects and so we have considered this in considerable detail. A plausible case can now be made for supposing that they are coherent objects which have been ejected at relativistic speeds L from the nuclei of galaxies at times when they erupt to give rise to strong radio source_ and other phenomena. -
Extragalactic Astronomy: the U Nivcre Bey Nd Our Galaxy
U1IJT RESUPE EU 1J3 199 021 775 dacon Eenneth Char TITLE Extragalactic Astronomy: The U nivcre Bey nd Our Galaxy. American Astronomical Society, Princeton, N.J. SFONS AGENCY National Aeronautics and Space Administra ashingtonl D.C.; National Science Foundation, Washington, D.C. REPOBT NO NASA-i:T-129 PUB DATE Sep 76 NOTE 44p.; FOF ltEd aocunents, _e SE 021 773-776 AVAII,AULE Superintendent of Documents, U.S. G-vernment Prin ing Office, Washington, D.C. 20402(5 ock Number 033-000-00657-8, $1.30) E.-RS PE10E 1F-$0.03 HC-$2.06 Plus Postige. DESCilIPTORS *Astronomy; Curriculum; *Instructional Materials; Science Education; *Scientific iesearch; Secondary Education; *Secondary School Science; *Space Sciences TIF NASA; National Aeronautics and Space Administration BSTRACT This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers or secondary school chemistry, physics, and earth science. The material is presented in three parts: one section provides the fundamental content of extragalactic astronomy, another section discusses modern discoveries in detail, and the last section summarizes the earlier discussions within the structure of the Big Bang Theory of Evolution. Each of the three sections is followed by student exercises and activities, laboratory projects, and questions and answers. The glossary contains unfamiliar terms used in the text and a collection of teacher aids such as literature references and audiovisual materials. (111) ***** *** * ** ** ***************** ********** Document., acquired by IC include many informal unpublished aterials not available from other sources. ERIC makes every effort * * to obtain the best copy available. Nevertheless, items of marginal * * reproducibility are often encountered and tbis affects the quality * * of the microfiche and hardcopy reproductions ERIC makes available * * via the ERIC Document Reproduction Service (EDRS). -
Abstract Handbook
July 8-11, 2008 Cambridge, Massachusetts at the Harvard Student Organization Center at Hilles Hosted by the Chandra X-Ray Center Chandra X-Ray Center Smithsonian Astrophysical Observatory Scientific Organizing Committee: SOC Chairs: Ralph Kraft and Aneta Siemiginowska (SAO) Elizabeth Blanton (BU) Geoff Bicknell (Stromlo) Annalisa Celotti (SISSA) Jean Eilek (NRAO/NMIMT) Dan Evans (Harvard) Heino Falcke (Radboud) Paul Green (SAO) Martin Hardcastle (Hertfordshire) Dan Harris (SAO) Sebastian Heinz (UWisc) Jun Kataoka (TokyoTech) Herman Marshall (MIT) Paul Nulsen (SAO) Chris Reynolds (UMd) Jeremy Sanders (IoA) Dan Schwartz (SAO) Marek Sikora (CAMK, Warsaw) Local Organizing Committee Paul Green (Chair) Lauren Deknis Ryan Foltz Michele Hall Michelle Henson Cathy Oskin Lisa Paton Su Tuttle This Chandra science workshop is sponsored by the Chandra Director’s Office (CDO) at the Chandra X-ray Center (CXC), part of the Smithsonian Astrophysical Observatory in Cambridge, MA. RADIO GALAXIES IN THE CHANDRA ERA July 8-11, 2008 PROGRAM TUESDAY JULY 8 9:00-9:15 Opening Remarks - Ralph Kraft and Harvey Tananbaum 9:15-9:50 Invited Talk: Dave De Young Radio Galaxies in X-ray Light: Problems and Processes SESSION I - RADIO GALAXIES IN THE LOCAL UNIVERSE CHAIR: DAN SCHWARTZ 9:50-10:25 Invited Talk: Mark Birkinshaw AGN Jet Flows 10:25-10:40 Talk I-1 : D. Harris Impulsive Brightening and Variability Timescales in the M87 Jet 10:40-11:10 Coffee 11:10-11:25 Talk I-2 : R. Daly The Properties of the Most Powerful FRII Radio Galaxies 11:25-11:40 Talk I-3 : C. Jones Centaurus A 11:40-11:55 Talk I-4 : R. -
Structure in Radio Galaxies
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FY13 High-Level Deliverables
National Optical Astronomy Observatory Fiscal Year Annual Report for FY 2013 (1 October 2012 – 30 September 2013) Submitted to the National Science Foundation Pursuant to Cooperative Support Agreement No. AST-0950945 13 December 2013 Revised 18 September 2014 Contents NOAO MISSION PROFILE .................................................................................................... 1 1 EXECUTIVE SUMMARY ................................................................................................ 2 2 NOAO ACCOMPLISHMENTS ....................................................................................... 4 2.1 Achievements ..................................................................................................... 4 2.2 Status of Vision and Goals ................................................................................. 5 2.2.1 Status of FY13 High-Level Deliverables ............................................ 5 2.2.2 FY13 Planned vs. Actual Spending and Revenues .............................. 8 2.3 Challenges and Their Impacts ............................................................................ 9 3 SCIENTIFIC ACTIVITIES AND FINDINGS .............................................................. 11 3.1 Cerro Tololo Inter-American Observatory ....................................................... 11 3.2 Kitt Peak National Observatory ....................................................................... 14 3.3 Gemini Observatory ........................................................................................