A Misty Cloud on Our Doorstep
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Arxiv:1612.03165V3 [Astro-Ph.HE] 12 Sep 2017 – 2 –
The second catalog of flaring gamma-ray sources from the Fermi All-sky Variability Analysis S. Abdollahi1, M. Ackermann2, M. Ajello3;4, A. Albert5, L. Baldini6, J. Ballet7, G. Barbiellini8;9, D. Bastieri10;11, J. Becerra Gonzalez12;13, R. Bellazzini14, E. Bissaldi15, R. D. Blandford16, E. D. Bloom16, R. Bonino17;18, E. Bottacini16, J. Bregeon19, P. Bruel20, R. Buehler2;21, S. Buson12;22, R. A. Cameron16, M. Caragiulo23;15, P. A. Caraveo24, E. Cavazzuti25, C. Cecchi26;27, A. Chekhtman28, C. C. Cheung29, G. Chiaro11, S. Ciprini25;26, J. Conrad30;31;32, D. Costantin11, F. Costanza15, S. Cutini25;26, F. D'Ammando33;34, F. de Palma15;35, A. Desai3, R. Desiante17;36, S. W. Digel16, N. Di Lalla6, M. Di Mauro16, L. Di Venere23;15, B. Donaggio10, P. S. Drell16, C. Favuzzi23;15, S. J. Fegan20, E. C. Ferrara12, W. B. Focke16, A. Franckowiak2, Y. Fukazawa1, S. Funk37, P. Fusco23;15, F. Gargano15, D. Gasparrini25;26, N. Giglietto23;15, M. Giomi2;59, F. Giordano23;15, M. Giroletti33, T. Glanzman16, D. Green13;12, I. A. Grenier7, J. E. Grove29, L. Guillemot38;39, S. Guiriec12;22, E. Hays12, D. Horan20, T. Jogler40, G. J´ohannesson41, A. S. Johnson16, D. Kocevski12;42, M. Kuss14, G. La Mura11, S. Larsson43;31, L. Latronico17, J. Li44, F. Longo8;9, F. Loparco23;15, M. N. Lovellette29, P. Lubrano26, J. D. Magill13, S. Maldera17, A. Manfreda6, M. Mayer2, M. N. Mazziotta15, P. F. Michelson16, W. Mitthumsiri45, T. Mizuno46, M. E. Monzani16, A. Morselli47, I. V. Moskalenko16, M. Negro17;18, E. Nuss19, T. Ohsugi46, N. Omodei16, M. Orienti33, E. -
Limits from the Hubble Space Telescope on a Point Source in SN 1987A
Limits from the Hubble Space Telescope on a Point Source in SN 1987A The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Graves, Genevieve J. M., Peter M. Challis, Roger A. Chevalier, Arlin Crotts, Alexei V. Filippenko, Claes Fransson, Peter Garnavich, et al. 2005. “Limits from the Hubble Space Telescopeon a Point Source in SN 1987A.” The Astrophysical Journal 629 (2): 944–59. https:// doi.org/10.1086/431422. Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:41399924 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA The Astrophysical Journal, 629:944–959, 2005 August 20 # 2005. The American Astronomical Society. All rights reserved. Printed in U.S.A. LIMITS FROM THE HUBBLE SPACE TELESCOPE ON A POINT SOURCE IN SN 1987A Genevieve J. M. Graves,1, 2 Peter M. Challis,2 Roger A. Chevalier,3 Arlin Crotts,4 Alexei V. Filippenko,5 Claes Fransson,6 Peter Garnavich,7 Robert P. Kirshner,2 Weidong Li,5 Peter Lundqvist,6 Richard McCray,8 Nino Panagia,9 Mark M. Phillips,10 Chun J. S. Pun,11,12 Brian P. Schmidt,13 George Sonneborn,11 Nicholas B. Suntzeff,14 Lifan Wang,15 and J. Craig Wheeler16 Received 2005 January 27; accepted 2005 April 26 ABSTRACT We observed supernova 1987A (SN 1987A) with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST ) in 1999 September and again with the Advanced Camera for Surveys (ACS) on the HST in 2003 November. -
The AAVSO DSLR Observing Manual
The AAVSO DSLR Observing Manual AAVSO 49 Bay State Road Cambridge, MA 02138 email: [email protected] Version 1.2 Copyright 2014 AAVSO Foreword This manual is a basic introduction and guide to using a DSLR camera to make variable star observations. The target audience is first-time beginner to intermediate level DSLR observers, although many advanced observers may find the content contained herein useful. The AAVSO DSLR Observing Manual was inspired by the great interest in DSLR photometry witnessed during the AAVSO’s Citizen Sky program. Consumer-grade imaging devices are rapidly evolving, so we have elected to write this manual to be as general as possible and move the software and camera-specific topics to the AAVSO DSLR forums. If you find an area where this document could use improvement, please let us know. Please send any feedback or suggestions to [email protected]. Most of the content for these chapters was written during the third Citizen Sky workshop during March 22-24, 2013 at the AAVSO. The persons responsible for creation of most of the content in the chapters are: Chapter 1 (Introduction): Colin Littlefield, Paul Norris, Richard (Doc) Kinne, Matthew Templeton Chapter 2 (Equipment overview): Roger Pieri, Rebecca Jackson, Michael Brewster, Matthew Templeton Chapter 3 (Software overview): Mark Blackford, Heinz-Bernd Eggenstein, Martin Connors, Ian Doktor Chapters 4 & 5 (Image acquisition and processing): Robert Buchheim, Donald Collins, Tim Hager, Bob Manske, Matthew Templeton Chapter 6 (Transformation): Brian Kloppenborg, Arne Henden Chapter 7 (Observing program): Des Loughney, Mike Simonsen, Todd Brown Various figures: Paul Valleli Clear skies, and Good Observing! Arne Henden, Director Rebecca Turner, Operations Director Brian Kloppenborg, Editor Matthew Templeton, Science Director Elizabeth Waagen, Senior Technical Assistant American Association of Variable Star Observers Cambridge, Massachusetts June 2014 i Index 1. -
THE 1000 BRIGHTEST HIPASS GALAXIES: H I PROPERTIES B
The Astronomical Journal, 128:16–46, 2004 July A # 2004. The American Astronomical Society. All rights reserved. Printed in U.S.A. THE 1000 BRIGHTEST HIPASS GALAXIES: H i PROPERTIES B. S. Koribalski,1 L. Staveley-Smith,1 V. A. Kilborn,1, 2 S. D. Ryder,3 R. C. Kraan-Korteweg,4 E. V. Ryan-Weber,1, 5 R. D. Ekers,1 H. Jerjen,6 P. A. Henning,7 M. E. Putman,8 M. A. Zwaan,5, 9 W. J. G. de Blok,1,10 M. R. Calabretta,1 M. J. Disney,10 R. F. Minchin,10 R. Bhathal,11 P. J. Boyce,10 M. J. Drinkwater,12 K. C. Freeman,6 B. K. Gibson,2 A. J. Green,13 R. F. Haynes,1 S. Juraszek,13 M. J. Kesteven,1 P. M. Knezek,14 S. Mader,1 M. Marquarding,1 M. Meyer,5 J. R. Mould,15 T. Oosterloo,16 J. O’Brien,1,6 R. M. Price,7 E. M. Sadler,13 A. Schro¨der,17 I. M. Stewart,17 F. Stootman,11 M. Waugh,1, 5 B. E. Warren,1, 6 R. L. Webster,5 and A. E. Wright1 Received 2002 October 30; accepted 2004 April 7 ABSTRACT We present the HIPASS Bright Galaxy Catalog (BGC), which contains the 1000 H i brightest galaxies in the southern sky as obtained from the H i Parkes All-Sky Survey (HIPASS). The selection of the brightest sources is basedontheirHi peak flux density (Speak k116 mJy) as measured from the spatially integrated HIPASS spectrum. 7 ; 10 The derived H i masses range from 10 to 4 10 M . -
Highlights of Discoveries for $\Delta $ Scuti Variable Stars from the Kepler
Highlights of Discoveries for δ Scuti Variable Stars from the Kepler Era Joyce Ann Guzik1,∗ 1Los Alamos National Laboratory, Los Alamos, NM 87545 USA Correspondence*: Joyce Ann Guzik [email protected] ABSTRACT The NASA Kepler and follow-on K2 mission (2009-2018) left a legacy of data and discoveries, finding thousands of exoplanets, and also obtaining high-precision long time-series data for hundreds of thousands of stars, including many types of pulsating variables. Here we highlight a few of the ongoing discoveries from Kepler data on δ Scuti pulsating variables, which are core hydrogen-burning stars of about twice the mass of the Sun. We discuss many unsolved problems surrounding the properties of the variability in these stars, and the progress enabled by Kepler data in using pulsations to infer their interior structure, a field of research known as asteroseismology. Keywords: Stars: δ Scuti, Stars: γ Doradus, NASA Kepler Mission, asteroseismology, stellar pulsation 1 INTRODUCTION The long time-series, high-cadence, high-precision photometric observations of the NASA Kepler (2009- 2013) [Borucki et al., 2010; Gilliland et al., 2010; Koch et al., 2010] and follow-on K2 (2014-2018) [Howell et al., 2014] missions have revolutionized the study of stellar variability. The amount and quality of data provided by Kepler is nearly overwhelming, and will motivate follow-on observations and generate new discoveries for decades to come. Here we review some highlights of discoveries for δ Scuti (abbreviated as δ Sct) variable stars from the Kepler mission. The δ Sct variables are pre-main-sequence, main-sequence (core hydrogen-burning), or post-main-sequence (undergoing core contraction after core hydrogen burning, and beginning shell hydrogen burning) stars with spectral types A through mid-F, and masses around 2 solar masses. -
Arxiv:2009.04090V2 [Astro-Ph.GA] 14 Sep 2020
Research in Astronomy and Astrophysics manuscript no. (LATEX: tikhonov˙Dorado.tex; printed on September 15, 2020; 1:01) Distance to the Dorado galaxy group N.A. Tikhonov1, O.A. Galazutdinova1 Special Astrophysical Observatory, Nizhnij Arkhyz, Karachai-Cherkessian Republic, Russia 369167; [email protected] Abstract Based on the archival images of the Hubble Space Telescope, stellar photometry of the brightest galaxies of the Dorado group:NGC 1433, NGC1533,NGC1566and NGC1672 was carried out. Red giants were found on the obtained CM diagrams and distances to the galaxies were measured using the TRGB method. The obtained values: 14.2±1.2, 15.1±0.9, 14.9 ± 1.0 and 15.9 ± 0.9 Mpc, show that all the named galaxies are located approximately at the same distances and form a scattered group with an average distance D = 15.0 Mpc. It was found that blue and red supergiants are visible in the hydrogen arm between the galaxies NGC1533 and IC2038, and form a ring structure in the lenticular galaxy NGC1533, at a distance of 3.6 kpc from the center. The high metallicity of these stars (Z = 0.02) indicates their origin from NGC1533 gas. Key words: groups of galaxies, Dorado group, stellar photometry of galaxies: TRGB- method, distances to galaxies, galaxies NGC1433, NGC 1533, NGC1566, NGC1672 1 INTRODUCTION arXiv:2009.04090v2 [astro-ph.GA] 14 Sep 2020 A concentration of galaxies of different types and luminosities can be observed in the southern constella- tion Dorado. Among them, Shobbrook (1966) identified 11 galaxies, which, in his opinion, constituted one group, which he called “Dorado”. -
Fundamental Parameters of Wolf-Rayet Stars VI
Astron. Astrophys. 320, 500–524 (1997) ASTRONOMY AND ASTROPHYSICS Fundamental parameters of Wolf-Rayet stars VI. Large Magellanic Cloud WNL stars? P.A.Crowther and L.J. Smith Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK Received 5 February 1996 / Accepted 26 June 1996 Abstract. We present a detailed, quantitative study of late WN Key words: stars: Wolf-Rayet;mass-loss; evolution; fundamen- (WNL) stars in the LMC, based on new optical spectroscopy tal parameters – galaxies: Magellanic Clouds (AAT, MSO) and the Hillier (1990) atmospheric model. In a pre- vious paper (Crowther et al. 1995a), we showed that 4 out of the 10 known LMC Ofpe/WN9 stars should be re-classified WN9– 10. We now present observations of the remaining stars (except the LBV R127), and show that they are also WNL (WN9–11) 1. Introduction stars, with the exception of R99. Our total sample consists of 17 stars, and represents all but one of the single LMC WN6– Quantitative studies of hot luminous stars in galaxies are im- 11 population and allows a direct comparison with the stellar portant for a number of reasons. First, and probably foremost, parameters and chemical abundances of Galactic WNL stars is the information they provide on the effect of the environment (Crowther et al. 1995b; Hamann et al. 1995a). Previously un- on such fundamental properties as the mass-loss rate and stellar published ultraviolet (HST-FOS, IUE-HIRES) spectroscopy are evolution. In the standard picture (e.g. Maeder & Meynet 1987) presented for a subset of our programme stars. -
Properties of Bright Variable Stars in Unusual Metal Rich
PROPERTIES OF BRIGHT VARIABLE STARS IN UNUSUAL METAL RICH CLUSTER NGC 6388 Gustavo A. Cardona V. AThesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2011 Committee: Andrew C. Layden, Advisor John B. Laird Dale W. Smith ii ABSTRACT Andrew C. Layden, Advisor We have searched for Long Period Variable (LPV) stars in the metal-rich cluster NGC 6388 using time series photometry in the V and I bandpasses. A CMD was created, which displays the tilted red HB at V = 17.5 mag. and the unusual prominent blue HB at V = 17 to 18 mag. Time-series photometry and periods have been presented for 63 variable stars, of which 30 are newly discovered variables. Of the known variables nine are LPVs. We are the first to present light curves for these stars and to classify their variability types. We find 3 LPVs as Mira, 6 as Semi-regulars (SR) and 1 as Irregular (Irr.), 18 are RR Lyrae, of which we present complementary time series and period for 14 of these stars, and 7 are Population II Cepheids, of which we present complementary time series and period for 4 of them. The newly discovered variables are all suspected LPV stars and we classified them, using time series photometry and periods, as Mira for 1 star, SR for 15 stars, Irr for 7 stars, Suspected Variables for 7 stars, out of which there are 3 very bright stars that could have overexposed the CCD, with no definite borderline between the SR and Irr stars. -
A Comprehensive Comparative Test of Seven Widely Used Spectral Synthesis Models Against Multi-Band Photometry of Young Massive-Star Clusters
MNRAS 457, 4296–4322 (2016) doi:10.1093/mnras/stw150 A comprehensive comparative test of seven widely used spectral synthesis models against multi-band photometry of young massive-star clusters A. Wofford,1‹ S. Charlot,1‹ G. Bruzual,2 J. J. Eldridge,3‹ D. Calzetti,4 A. Adamo,5 M. Cignoni,6 S. E. de Mink,7 D. A. Gouliermis,8,9 K. Grasha,4 E. K. Grebel,10 J. C. Lee,6 G. Ostlin,¨ 5 L. J. Smith,6 L. Ubeda6 and E. Zackrisson11 1Sorbonne Universites,´ UPMC-CNRS, UMR7095, Institut d’Astrophysique de Paris, F-75014 Paris, France 2Instituto de Radioastronom´ıa y Astrof´ısica, UNAM, 58089 Morelia, Michoacan,´ Mexico´ 3Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand 4Department of Astronomy, University of Massachusetts – Amherst, Amherst, MA 01003, USA 5Department of Astronomy, The Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm, Sweden Downloaded from 6Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 7Anton Pannekoek Astronomical Institute, University of Amsterdam, NL-1090 GE Amsterdam, the Netherlands 8Institute for Theoretical Astrophysics, Centre for Astronomy, University of Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg, Germany 9Max Planck Institute for Astronomy, Konigstuhl¨ 17, D-69117 Heidelberg, Germany 10Astronomisches Rechen-Institut, Zentrum fur¨ Astronomie der Universitat¨ Heidelberg, Monchhofstr.¨ 12-14, D-Heidelberg, Germany 11Department of Physics and Astronomy, Uppsala University, Box 515, SE-751 20 Uppsala, Sweden http://mnras.oxfordjournals.org/ Accepted 2016 January 14. Received 2016 January 14; in original form 2015 November 30 ABSTRACT We test the predictions of spectral synthesis models based on seven different massive-star prescriptions against Legacy ExtraGalactic UV Survey (LEGUS) observations of eight young massive clusters in two local galaxies, NGC 1566 and NGC 5253, chosen because predictions at Universita degli Studi di Pisa on October 14, 2016 of all seven models are available at the published galactic metallicities. -
Stsci Newsletter: 1991 Volume 008 Issue 03
SPACE 'fEIFSCOPE SOENCE ...______._.INSTITUIE Operated for NASA by AURA November 1991 Vol. 8No. 3 HIGHLIGHTS OF THIS ISSUE: HSTSCIENCE HIGHLIGHTS WF/PC OBSERVATIONS OF THE STELLAR O NEW SCIENCE RESULTS ON M87, CRAB PULSAR CUSP IN M87 O COSTAR PROGRESSING WELL The photograph on the left shows one of a set of images of the central regions of the giant ellipti O ANSWERS TO YOUR QUESTIONS ABOUT HST DATA cal galaxy M87, obtained in June 1991 withHSI's Wide Field and Planetary Camera {WF/PC). 0 CYCLE 2 PEER REVIEW UNDERWAY Analysis of these images has revealed a stellar cusp in the core of M87, consistent with the pres ence of a massive black hole in its nucleus. A combined approach of image deconvolution and modelling has made it possible to investigate the starlight distribution in M87 down to a limiting radius of about 0'.'04 from the nucleus (or about 3 pc from the nucleus if the Virgo cluster is at 16 Mpc). The results show that the central struc ture of M87 can be described by three compo nents: a power-law starlight profile with an r·114 slope which continues unabated into the center, an unresolved central point source, and optical coun terparts of the jet knots identified by VLBI obser vations. In both the V- and /-band Planetary Camera images, the stellar cusp is consistent with the black-hole model proposed for M87 by Young et al. in 1978; in this model, there is a central mas sive object of about 3 x 109 Me. -
ESO Annual Report 2004 ESO Annual Report 2004 Presented to the Council by the Director General Dr
ESO Annual Report 2004 ESO Annual Report 2004 presented to the Council by the Director General Dr. Catherine Cesarsky View of La Silla from the 3.6-m telescope. ESO is the foremost intergovernmental European Science and Technology organi- sation in the field of ground-based as- trophysics. It is supported by eleven coun- tries: Belgium, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Sweden, Switzerland and the United Kingdom. Created in 1962, ESO provides state-of- the-art research facilities to European astronomers and astrophysicists. In pur- suit of this task, ESO’s activities cover a wide spectrum including the design and construction of world-class ground-based observational facilities for the member- state scientists, large telescope projects, design of innovative scientific instruments, developing new and advanced techno- logies, furthering European co-operation and carrying out European educational programmes. ESO operates at three sites in the Ataca- ma desert region of Chile. The first site The VLT is a most unusual telescope, is at La Silla, a mountain 600 km north of based on the latest technology. It is not Santiago de Chile, at 2 400 m altitude. just one, but an array of 4 telescopes, It is equipped with several optical tele- each with a main mirror of 8.2-m diame- scopes with mirror diameters of up to ter. With one such telescope, images 3.6-metres. The 3.5-m New Technology of celestial objects as faint as magnitude Telescope (NTT) was the first in the 30 have been obtained in a one-hour ex- world to have a computer-controlled main posure. -
Download the 2016 Spring Deep-Sky Challenge
Deep-sky Challenge 2016 Spring Southern Star Party Explore the Local Group Bonnievale, South Africa Hello! And thanks for taking up the challenge at this SSP! The theme for this Challenge is Galaxies of the Local Group. I’ve written up some notes about galaxies & galaxy clusters (pp 3 & 4 of this document). Johan Brink Peter Harvey Late-October is prime time for galaxy viewing, and you’ll be exploring the James Smith best the sky has to offer. All the objects are visible in binoculars, just make sure you’re properly dark adapted to get the best view. Galaxy viewing starts right after sunset, when the centre of our own Milky Way is visible low in the west. The edge of our spiral disk is draped along the horizon, from Carina in the south to Cygnus in the north. As the night progresses the action turns north- and east-ward as Orion rises, drawing the Milky Way up with it. Before daybreak, the Milky Way spans from Perseus and Auriga in the north to Crux in the South. Meanwhile, the Large and Small Magellanic Clouds are in pole position for observing. The SMC is perfectly placed at the start of the evening (it culminates at 21:00 on November 30), while the LMC rises throughout the course of the night. Many hundreds of deep-sky objects are on display in the two Clouds, so come prepared! Soon after nightfall, the rich galactic fields of Sculptor and Grus are in view. Gems like Caroline’s Galaxy (NGC 253), the Black-Bottomed Galaxy (NGC 247), the Sculptor Pinwheel (NGC 300), and the String of Pearls (NGC 55) are keen to be viewed.