Hubble Sees Elegant Spiral Hiding a Hungry Monster 19 October 2015

Total Page：16

File Type：pdf, Size：1020Kb

Image: Hubble sees elegant spiral hiding a hungry monster 19 October 2015 dark secret in its core—a massive black hole that is consuming the surrounding gas. This is known as an active galactic nucleus (AGN), and is revealed by characteristic features in the spectrum of light from the galaxy and by X-rays produced close to the black hole as the hot gas plunges towards it. Most galaxies are thought to contain a black hole at the center. NGC 4639 is in fact a very weak example of an AGN, demonstrating that AGNs exist over a large range of activity, from galaxies like NGC 4639 to distant quasars, where the parent galaxy is almost completely dominated by the emissions from the AGN. Provided by NASA Credit: ESA/Hubble & NASA NGC 4639 is a beautiful example of a type of galaxy known as a barred spiral. It lies over 70 million light-years away in the constellation of Virgo and is one of about 1,500 galaxies that make up the Virgo Cluster. In this image, taken by the NASA/ESA Hubble Space Telescope, one can clearly see the bar running through the bright, round core of the galaxy. Bars are found in around two-thirds of spiral galaxies, and are thought to be a natural phase in their evolution. The galaxy's spiral arms are sprinkled with bright regions of active star formation. Each of these tiny jewels is actually several hundred light-years across and contains hundreds or thousands of newly formed stars. But NGC 4639 also conceals a 1 / 2 APA citation: Image: Hubble sees elegant spiral hiding a hungry monster (2015, October 19) retrieved 27 September 2021 from https://phys.org/news/2015-10-image-hubble-elegant-spiral-hungry.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. 2 / 2 Powered by TCPDF (www.tcpdf.org).

Copy Link

Recommended publications

The Distribution of Absorbing Column Densities Among Seyfert 2 Galaxies
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server The distribution of absorbing column densities among Seyfert 2 galaxies G. Risaliti Dipartimento di Astronomia e Scienza dello Spazio, Univerità di Firenze, L. E. Fermi 5, I-50125, Firenze, Italy R. Maiolino and M. Salvati Osservatorio Astrofisico di Arcetri, L. E. Fermi 5, I-50125 Firenze, Italy ABSTRACT We use hard X-ray data for an “optimal” sample of Seyfert 2 galaxies to derive the distribution of the gaseous absorbing column densities among obscured active nuclei in the local Universe. Of all Seyfert 2 galaxies in the sample, 75% are heavily obscured 23 2 24 2 (NH > 10 cm− ) and about half are Compton thick (NH > 10 cm− ). Intermediate type 1.8–1.9 Seyferts are characterized by an average NH much lower than “strict” Seyfert 2s. No correlation is found between NH and the intrinsic luminosity of the nuclear source. This NH distribution has important consequences for the synthesis of the cosmic X-ray background. Also, the large fraction of Compton thick objects implies that most of the obscuring gas is located within a radius of a few 10 pc from the nucleus. Subject headings: Galaxies: active — Galaxies: nuclei — Galaxies: Seyfert — X-rays: galaxies 1. Introduction According to the so-called unified model (Antonucci 1993) the same engine is at work in all Active Galactic Nuclei (AGNs). The differences between type 1 and type 2 AGNs are ascribed solely to orientation effects: our line of sight to the nucleus may (type 2) or may not (type 1) be obstructed by optically thick material, perhaps distributed in a toroidal geometry.
[Show full text]
Gone Without a Bang: an Archival HST Survey for Disappearing Massive Stars
MNRAS 453, 2885–2900 (2015) doi:10.1093/mnras/stv1809 Gone without a bang: an archival HST survey for disappearing massive stars Thomas M. Reynolds,1,2‹ Morgan Fraser1 and Gerard Gilmore1 1Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 2Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Vais¨ al¨ antie¨ 20, FI-21500 Piikkio,¨ Finland Downloaded from Accepted 2015 August 4. Received 2015 July 16; in original form 2015 May 27 ABSTRACT It has been argued that a substantial fraction of massive stars may end their lives without http://mnras.oxfordjournals.org/ an optically bright supernova (SN), but rather collapse to form a black hole. Such an event would not be detected by current SN surveys, which are focused on finding bright transients. Kochanek et al. proposed a novel survey for such events, using repeated observations of nearby galaxies to search for the disappearance of a massive star. We present such a survey, using the first systematic analysis of archival Hubble Space Telescope images of nearby galaxies with the aim of identifying evolved massive stars which have disappeared, without an accompanying optically bright SN. We consider a sample of 15 galaxies, with at least three epochs of Hubble Space Telescope imaging taken between 1994 and 2013. Within this data, we find one candidate at CERN - European Organization for Nuclear Research on September 15, 2016 which is consistent with a 25–30 M yellow supergiant which has undergone an optically dark core-collapse. Key words: stars: evolution – stars: massive – supernovae: general. plosion, and Type IIL (Linear) SNe which have a steady decline 1 INTRODUCTION in luminosity from peak.
[Show full text]
Distances to PHANGS Galaxies: New Tip of the Red Giant Branch Measurements and Adopted Distances
MNRAS 501, 3621–3639 (2021) doi:10.1093/mnras/staa3668 Advance Access publication 2020 November 25 Distances to PHANGS galaxies: New tip of the red giant branch measurements and adopted distances Gagandeep S. Anand ,1,2‹† Janice C. Lee,1 Schuyler D. Van Dyk ,1 Adam K. Leroy,3 Erik Rosolowsky ,4 Eva Schinnerer,5 Kirsten Larson,1 Ehsan Kourkchi,2 Kathryn Kreckel ,6 Downloaded from https://academic.oup.com/mnras/article/501/3/3621/6006291 by California Institute of Technology user on 25 January 2021 Fabian Scheuermann,6 Luca Rizzi,7 David Thilker ,8 R. Brent Tully,2 Frank Bigiel,9 Guillermo A. Blanc,10,11 Med´ eric´ Boquien,12 Rupali Chandar,13 Daniel Dale,14 Eric Emsellem,15,16 Sinan Deger,1 Simon C. O. Glover ,17 Kathryn Grasha ,18 Brent Groves,18,19 Ralf S. Klessen ,17,20 J. M. Diederik Kruijssen ,21 Miguel Querejeta,22 Patricia Sanchez-Bl´ azquez,´ 23 Andreas Schruba,24 Jordan Turner ,14 Leonardo Ubeda,25 Thomas G. Williams 5 and Brad Whitmore25 Afﬁliations are listed at the end of the paper Accepted 2020 November 20. Received 2020 November 13; in original form 2020 August 24 ABSTRACT PHANGS-HST is an ultraviolet-optical imaging survey of 38 spiral galaxies within ∼20 Mpc. Combined with the PHANGS- ALMA, PHANGS-MUSE surveys and other multiwavelength data, the data set will provide an unprecedented look into the connections between young stars, H II regions, and cold molecular gas in these nearby star-forming galaxies. Accurate distances are needed to transform measured observables into physical parameters (e.g.
[Show full text]
May 2013 BRAS Newsletter
www.brastro.org May 2013 What's in this issue: PRESIDENT'S MESSAGE .............................................................................................................................. 2 NOTES FROM THE VICE PRESIDENT ........................................................................................................... 3 MESSAGE FROM THE HRPO ...................................................................................................................... 4 OBSERVING NOTES ..................................................................................................................................... 5 DEEP SKY OBJECTS ................................................................................................................................... 6 MAY ASTRONOMICAL EVENTS .................................................................................................................... 7 TREASURER’S NOTES ................................................................................................................................. 8 PREVIOUS MEETING MINUTES .................................................................................................................... 9 IMPORTANT NOTE: This month's meeting will be held on Saturday, May 18th at LIGO. PRESIDENT'S MESSAGE Hi Everyone, April was quite a busy month and the busiest day was International Astronomy Day. As you may have heard, we had the highest attendance at our Astronomy Day festivities at the HRPO ever. Approximately 770 people attended this year
[Show full text]
Synapses of Active Galactic Nuclei: Comparing X-Ray and Optical Classifications Using Artificial Neural Networks?
A&A 567, A92 (2014) Astronomy DOI: 10.1051/0004-6361/201322592 & c ESO 2014 Astrophysics Synapses of active galactic nuclei: Comparing X-ray and optical classifications using artificial neural networks? O. González-Martín1;2;??, D. Díaz-González3, J. A. Acosta-Pulido1;2, J. Masegosa4, I. E. Papadakis5;6, J. M. Rodríguez-Espinosa1;2, I. Márquez4, and L. Hernández-García4 1 Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea s/n, 38205 La Laguna, Spain e-mail: [email protected] 2 Departamento de Astrofísica, Universidad de La Laguna (ULL), 38205 La Laguna, Spain 3 Shidix Technologies, 38320, La Laguna, Spain 4 Instituto de Astrofísica de Andalucía, CSIC, C/ Glorieta de la Astronomía s/n, 18005 Granada, Spain 5 Physics Department, University of Crete, PO Box 2208, 710 03 Heraklion, Crete, Greece 6 IESL, Foundation for Research and Technology, 711 10 Heraklion, Crete, Greece Received 2 September 2013 / Accepted 3 April 2014 ABSTRACT Context. Many classes of active galactic nuclei (AGN) have been defined entirely through optical wavelengths, while the X-ray spectra have been very useful to investigate their inner regions. However, optical and X-ray results show many discrepancies that have not been fully understood yet. Aims. The main purpose of the present paper is to study the synapses (i.e., connections) between X-ray and optical AGN classifications. Methods. For the first time, the newly implemented efluxer task allowed us to analyse broad band X-ray spectra of a sample of emission-line nuclei without any prior spectral fitting. Our sample comprises 162 spectra observed with XMM-Newton/pn of 90 lo- cal emission line nuclei in the Palomar sample.
[Show full text]
SAC's 110 Best of the NGC
SAC's 110 Best of the NGC by Paul Dickson Version: 1.4 | March 26, 1997 Copyright °c 1996, by Paul Dickson. All rights reserved If you purchased this book from Paul Dickson directly, please ignore this form. I already have most of this information. Why Should You Register This Book? Please register your copy of this book. I have done two book, SAC's 110 Best of the NGC and the Messier Logbook. In the works for late 1997 is a four volume set for the Herschel 400. q I am a beginner and I bought this book to get start with deep-sky observing. q I am an intermediate observer. I bought this book to observe these objects again. q I am an advance observer. I bought this book to add to my collect and/or re-observe these objects again. The book I'm registering is: q SAC's 110 Best of the NGC q Messier Logbook q I would like to purchase a copy of Herschel 400 book when it becomes available. Club Name: __________________________________________ Your Name: __________________________________________ Address: ____________________________________________ City: __________________ State: ____ Zip Code: _________ Mail this to: or E-mail it to: Paul Dickson 7714 N 36th Ave [email protected] Phoenix, AZ 85051-6401 After Observing the Messier Catalog, Try this Observing List: SAC's 110 Best of the NGC [email protected] http://www.seds.org/pub/info/newsletters/sacnews/html/sac.110.best.ngc.html SAC's 110 Best of the NGC is an observing list of some of the best objects after those in the Messier Catalog.
[Show full text]
The Virgo Supercluster
12-1 How Far Away Is It – The Virgo Supercluster The Virgo Supercluster {Abstract – In this segment of our “How far away is it” video book, we cover our local supercluster, the Virgo Supercluster. We begin with a description of the size, content and structure of the supercluster, including the formation of galaxy clusters and galaxy clouds. We then take a look at some of the galaxies in the Virgo Supercluster including: NGC 4314 with its ring in the core, NGC 5866, Zwicky 18, the beautiful NGC 2841, NGC 3079 with is central gaseous bubble, M100, M77 with its central supermassive black hole, NGC 3949, NGC 3310, NGC 4013, the unusual NGC 4522, NGC 4710 with its "X"-shaped bulge, and NGC 4414. At this point, we have enough distant galaxies to formulate Hubble’s Law and calculate Hubble’s Red Shift constant. From a distance ladder point of view, once we have the Hubble constant, and we can measure red shift, we can calculate distance. So we add Red Shift to our ladder. Then we continue with galaxy gazing with: NGC 1427A, NGC 3982, NGC 1300, NGC 5584, the dusty NGC 1316, NGC 4639, NGC 4319, NGC 3021 with is large number of Cepheid variables, NGC 3370, NGC 1309, and 7049. We end with a review of the distance ladder now that Red Shift has been added.} Introduction [Music: Antonio Vivaldi – “The Four Seasons – Winter” – Vivaldi composed "The Four Seasons" in 1723. "Winter" is peppered with silvery pizzicato notes from the high strings, calling to mind icy rain. The ending line for the accompanying sonnet reads "this is winter, which nonetheless brings its own delights." The galaxies of the Virgo Supercluster will also bring us their own visual and intellectual delight.] Superclusters are among the largest structures in the known Universe.
[Show full text]
DGSAT: Dwarf Galaxy Survey with Amateur Telescopes
Astronomy & Astrophysics manuscript no. arxiv30539 c ESO 2017 March 21, 2017 DGSAT: Dwarf Galaxy Survey with Amateur Telescopes II. A catalogue of isolated nearby edge-on disk galaxies and the discovery of new low surface brightness systems C. Henkel1;2, B. Javanmardi3, D. Mart´ınez-Delgado4, P. Kroupa5;6, and K. Teuwen7 1 Max-Planck-Institut fürRadioastronomie, Auf dem Hügel69, 53121 Bonn, Germany 2 Astronomy Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia 3 Argelander Institut fürAstronomie, UniversitätBonn, Auf dem Hügel71, 53121 Bonn, Germany 4 Astronomisches Rechen-Institut, Zentrum fürAstronomie, UniversitätHeidelberg, Mönchhofstr. 12{14, 69120 Heidelberg, Germany 5 Helmholtz Institut für Strahlen- und Kernphysik (HISKP), Universität Bonn, Nussallee 14{16, D-53121 Bonn, Germany 6 Charles University, Faculty of Mathematics and Physics, Astronomical Institute, V Holeˇsoviˇckách 2, CZ-18000 Praha 8, Czech Republic 7 Remote Observatories Southern Alps, Verclause, France Received date ; accepted date ABSTRACT The connection between the bulge mass or bulge luminosity in disk galaxies and the number, spatial and phase space distribution of associated dwarf galaxies is a dis- criminator between cosmological simulations related to galaxy formation in cold dark matter and generalised gravity models. Here, a nearby sample of isolated Milky Way- class edge-on galaxies is introduced, to facilitate observational campaigns to detect the associated families of dwarf galaxies at low surface brightness. Three galaxy pairs with at least one of the targets being edge-on are also introduced. Approximately 60% of the arXiv:1703.05356v2 [astro-ph.GA] 19 Mar 2017 catalogued isolated galaxies contain bulges of different size, while the remaining objects appear to be bulgeless.
[Show full text]
Open Thesis10.Pdf
The Pennsylvania State University The Graduate School The Eberly College of Science POPULATION SYNTHESIS AND ITS CONNECTION TO ASTRONOMICAL OBSERVABLES A Thesis in Astronomy and Astrophysics Michael S. Sipior c 2003 Michael S. Sipior Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy May 2003 We approve the thesis of Michael S. Sipior Date of Signature Michael Eracleous Assistant Professor of Astronomy and Astrophysics Thesis Advisor Chair of Committee Steinn Sigurdsson Assistant Professor of Astronomy and Astrophysics Gordon P. Garmire Evan Pugh Professor of Astronomy and Astrophysics W. Niel Brandt Associate Professor of Astronomy and Astrophysics L. Samuel Finn Professor of Physics Peter I. Mészáros Distinguished Professor of Astronomy and Astrophysics Head of the Department of Astronomy and Astrophysics Abstract In this thesis, I present a model used for binary population synthesis, and 8 use it to simulate a starburst of 2 10 M over a duration of 20 Myr. This × population reaches a maximum 2{10 keV luminosity of 4 1040 erg s−1, ∼ × attained at the end of the star formation episode, and sustained for a pe- riod of several hundreds of Myr by succeeding populations of XRBs with lighter companion stars. An important property of these results is the min- imal dependence on poorly-constrained values of the initial mass function (IMF) and the average mass ratio between accreting and donating stars in XRBs. The peak X-ray luminosity is shown to be consistent with recent observationally-motivated correlations between the star formation rate and total hard (2{10 keV) X-ray luminosity.
[Show full text]
THE LUMINOSITIES of SUPERNOVAE of TYPE Ia
THE LUMINOSITIES OF SUPERNOVAE OF TYPE Ia DERIVED FROM CEPHEID CALIBRATIONS Sidney van den Bergh Dominion Astrophysical Observatory 5071 West Saanich Road Victoria, British Columbia, V8X 4M6, Canada Electronic mail: [email protected] Received: 1996 January 17 Revised: - 2 - ABSTRACT Available data on the luminosities of supernovae of Type Ia (SNe Ia) that have been calibrated by Cepheids are collected and discussed. The objects in the present sample show a range of ~20 in luminosity. The data strongly confirm the suspicion that SNe Ia in early-type systems are, on average, fainter than those that occur in late-type galaxies. Historical observations of S Andromedae suggest that the maximum magnitude versus rate-of-decline relationship for SNe Ia exhibits a large intrinsic dispersion. This is not surprising because the amount of 56Ni that is produced, and other observable properties of SNe Ia, are expected to depend sensitively on how much fuel is ignited. Subject headings: cosmology-distance scale - stars: supernovae: general - stars: variables: Cepheids - 3 - 1. INTRODUCTION The first great distance scale controversy (Curtis 1921, Shapley 1921) was resolved when Edwin Hubble (1925) discovered Cepheid variables in M31 and M33. Ever since that time Cepheids have remained the cornerstone to the determination of extragalactic distances (Sandage 1972). Can Cepheids resolve the second great distance scale controversy between astronomers who believe that . -1 -1 . -1 -1 Ho 55 km s Mpc and those who think that Ho 80 km s Mpc ? Even with the Hubble Space Telescope (HST), it is not possible to study Cepheids out to distances at which the random motions of galaxies are negligible compared to the cosmic Hubble flow.
[Show full text]
NGC 4654: Gravitational Interaction Or Ram Pressure Stripping?
A&A 398, 525–539 (2003) Astronomy DOI: 10.1051/0004-6361:20021729 & c ESO 2003 Astrophysics NGC 4654: Gravitational interaction or ram pressure stripping? B. Vollmer? Max-Planck-Institut f¨ur Radioastronomie, Auf dem H¨ugel 69, 53121 Bonn, Germany Received 13 July 2001 / Accepted 5 November 2002 Abstract. The Virgo cluster spiral galaxy NGC 4654 is supposed to be a good candidate for ongoing ram pressure stripping based on its very asymmetric Hi distribution. However, this galaxy also shows an asymmetric stellar distribution. Numerical simulations using ram pressure as the only perturbation can produce a tail structure of the gas content, but cannot account for its kinematical structure. It is shown that a strong edge–on stripping event can produce an asymmetric stellar distribution up to 800 Myr after the stripping event, i.e. the galaxy’s closest passage to the cluster center. Simulations using a gravitational interaction with the companion galaxy NGC 4639 can account for the asymmetric stellar distribution of NGC 4654, but cannot reproduce the observed extended gas tail. Only a mixed interaction, gravitational and ram pressure, can reproduce all observed properties of NGC 4654. It is concluded that NGC 4654 had a tidal interaction 500 Myr ago and is continuing to experience ram pressure until the present day. ∼ Key words. galaxies: individual: NGC 4654 – galaxies: interactions – galaxies: ISM – galaxies: kinematics and dynamics 1. Introduction Table 1. Physical parameters of NGC 4654. Maps of the gas content of spiral galaxies in the Virgo clus- ter have revealed that the Hi disks of cluster spirals are dis- Other names UGC 7902 turbed and considerably reduced (Cayatte et al.
[Show full text]
Southern Sentinel Observing Session Notes
Southern Sentinel Observing Session Notes Observing Session - Thursday 24th April 2003 Date: 24 Apr 2002 (Local) Time: 2145-2345 NZDT (UT +12) Location: Pauanui, Coromandel Peninsula. 120 Minutes From Home. Weather: Clear, Mild and Calm conditions. Seeing: Limiting Magnitude 5.5, transparency 3.5/5, seeing 3/5 Moon: No Moon (Small Waxing Moon, Set) Equipment: 13.1" F5 Dob with Paracorr, TeleVue Eyepieces, UHC Filter After a break of three weeks this time, Michelle and I planned a long weekend at Pauanui with the inclusion of Anzac Day. The weather looked to be pretty good and was liked to be settled for the whole weekend. Arriving from Auckland at 9 PM at Pauanui, I was observing 45 minutes later after the obligatory unpacking and settling in. The conditions were mild and clear. The skies were dark and through the gap in the large pines a dark Northeast aspect presented a good chance to work at the Virgo Cluster again. There was no dew all night and the seeing was average to good. The plan for the whole weekend was the systematic logging of the whole Virgo Coma Berenices region. This would start tonight from Vindemiatrix past Rho Virginis. Objects seen were; Object Type Altitude Magnification Eyepiece ------ ---- -------- ------------- -------- NGC 4689 Galaxy 36.2° 114x TeleVue 17mm Nagler Type 4 NGC 4762 Galaxy 38.6° 114x TeleVue 17mm Nagler Type 4 NGC 4754 Galaxy 38.5° 114x TeleVue 17mm Nagler Type 4 NGC 4880 Galaxy 36.8° 114x TeleVue 17mm Nagler Type 4 NGC 4866 Galaxy 35.5° 114x TeleVue 17mm Nagler Type 4 NGC 4654 Galaxy 38.1° 114x
[Show full text]