219Th Meeting of the American Astronomical Society
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Luminous Blue Variables
Review Luminous Blue Variables Kerstin Weis 1* and Dominik J. Bomans 1,2,3 1 Astronomical Institute, Faculty for Physics and Astronomy, Ruhr University Bochum, 44801 Bochum, Germany 2 Department Plasmas with Complex Interactions, Ruhr University Bochum, 44801 Bochum, Germany 3 Ruhr Astroparticle and Plasma Physics (RAPP) Center, 44801 Bochum, Germany Received: 29 October 2019; Accepted: 18 February 2020; Published: 29 February 2020 Abstract: Luminous Blue Variables are massive evolved stars, here we introduce this outstanding class of objects. Described are the specific characteristics, the evolutionary state and what they are connected to other phases and types of massive stars. Our current knowledge of LBVs is limited by the fact that in comparison to other stellar classes and phases only a few “true” LBVs are known. This results from the lack of a unique, fast and always reliable identification scheme for LBVs. It literally takes time to get a true classification of a LBV. In addition the short duration of the LBV phase makes it even harder to catch and identify a star as LBV. We summarize here what is known so far, give an overview of the LBV population and the list of LBV host galaxies. LBV are clearly an important and still not fully understood phase in the live of (very) massive stars, especially due to the large and time variable mass loss during the LBV phase. We like to emphasize again the problem how to clearly identify LBV and that there are more than just one type of LBVs: The giant eruption LBVs or h Car analogs and the S Dor cycle LBVs. -
The Title of My
Research in Astronomy and Astrophysics manuscript no. (LATEX: cgw.tex; printed on January 14, 2020; 2:35) Constraints on individual supermassive binary black holes using observations of PSR J1909 3744 − Yi Feng1,2,3, Di Li1,3, Yan-Rong Li4 and Jian-Min Wang4 1 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China ; [email protected] 2 University of Chinese Academy of Sciences, Beijing 100049, China 3 CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 4 Institute of High Energy Physics, Chinese Academy of Sciences,19B Yuquan Road, Beijing 100049, China Abstract We perform a search for gravitational waves (GWs) from several supermassive binary black hole (SMBBH) candidates (NGC 5548, Mrk 231, OJ 287, PG 1302-102, NGC 4151, Ark 120 and 3C 66B) in long-term timing observations of the pulsar PSR J1909 3744 − obtained using the Parkes radio telescope. No statistically significant signals were found. We constrain the chirp masses of those SMBBH candidates and find the chirp mass of NGC 5548 and3C66Btobeless than2.4 109 M and 2.5 109 M (with 95% confidence), respectively. × ⊙ × ⊙ Our upperlimits remaina factor of 3 to 370 abovethe likely chirp masses for these candidates as estimated from other approaches. The observations processed here provide upper limits on the GW strain amplitude that improve upon the results from the first Parkes Pulsar Timing arXiv:1907.03460v2 [astro-ph.IM] 13 Jan 2020 Array data release by a factor of 2 to 7. We investigate how information about the orbital pa- rameters can help improve the search sensitivity for individual SMBBH systems. -
A Basic Requirement for Studying the Heavens Is Determining Where In
Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short). -
Effemeridi Astronomiche Di Milano Per L'anno
Informazioni su questo libro Si tratta della copia digitale di un libro che per generazioni è stato conservata negli scaffali di una biblioteca prima di essere digitalizzato da Google nell’ambito del progetto volto a rendere disponibili online i libri di tutto il mondo. Ha sopravvissuto abbastanza per non essere più protetto dai diritti di copyright e diventare di pubblico dominio. Un libro di pubblico dominio è un libro che non è mai stato protetto dal copyright o i cui termini legali di copyright sono scaduti. La classificazione di un libro come di pubblico dominio può variare da paese a paese. I libri di pubblico dominio sono l’anello di congiunzione con il passato, rappresentano un patrimonio storico, culturale e di conoscenza spesso difficile da scoprire. Commenti, note e altre annotazioni a margine presenti nel volume originale compariranno in questo file, come testimonianza del lungo viaggio percorso dal libro, dall’editore originale alla biblioteca, per giungere fino a te. Linee guide per l’utilizzo Google è orgoglioso di essere il partner delle biblioteche per digitalizzare i materiali di pubblico dominio e renderli universalmente disponibili. I libri di pubblico dominio appartengono al pubblico e noi ne siamo solamente i custodi. Tuttavia questo lavoro è oneroso, pertanto, per poter continuare ad offrire questo servizio abbiamo preso alcune iniziative per impedire l’utilizzo illecito da parte di soggetti commerciali, compresa l’imposizione di restrizioni sull’invio di query automatizzate. Inoltre ti chiediamo di: + Non fare un uso commerciale di questi file Abbiamo concepito Google Ricerca Libri per l’uso da parte dei singoli utenti privati e ti chiediamo di utilizzare questi file per uso personale e non a fini commerciali. -
Information Bulletin on Variable Stars
COMMISSIONS AND OF THE I A U INFORMATION BULLETIN ON VARIABLE STARS Nos November July EDITORS L SZABADOS K OLAH TECHNICAL EDITOR A HOLL TYPESETTING K ORI ADMINISTRATION Zs KOVARI EDITORIAL BOARD L A BALONA M BREGER E BUDDING M deGROOT E GUINAN D S HALL P HARMANEC M JERZYKIEWICZ K C LEUNG M RODONO N N SAMUS J SMAK C STERKEN Chair H BUDAPEST XI I Box HUNGARY URL httpwwwkonkolyhuIBVSIBVShtml HU ISSN COPYRIGHT NOTICE IBVS is published on b ehalf of the th and nd Commissions of the IAU by the Konkoly Observatory Budap est Hungary Individual issues could b e downloaded for scientic and educational purp oses free of charge Bibliographic information of the recent issues could b e entered to indexing sys tems No IBVS issues may b e stored in a public retrieval system in any form or by any means electronic or otherwise without the prior written p ermission of the publishers Prior written p ermission of the publishers is required for entering IBVS issues to an electronic indexing or bibliographic system to o CONTENTS C STERKEN A JONES B VOS I ZEGELAAR AM van GENDEREN M de GROOT On the Cyclicity of the S Dor Phases in AG Carinae ::::::::::::::::::::::::::::::::::::::::::::::::::: : J BOROVICKA L SAROUNOVA The Period and Lightcurve of NSV ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::: W LILLER AF JONES A New Very Long Period Variable Star in Norma ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::: EA KARITSKAYA VP GORANSKIJ Unusual Fading of V Cygni Cyg X in Early November ::::::::::::::::::::::::::::::::::::::: -
198 8Apj. . .329. .532K the Astrophysical Journal, 329:532-550
.532K The Astrophysical Journal, 329:532-550,1988 June 15 © 1988. The American Astronomical Society. All rights reserved. Printed in U.S.A. .329. 8ApJ. 198 THE OPTICAL CONTINUA OF EXTRAGALACTIC RADIO JETS1 William C. Keel Sterrewacht Leiden Received 1987 August 11 ; accepted 1987 December 11 ABSTRACT Multicolor optical images have been used to measure the broad-band spectral shapes of radio jets known to show optical counterparts, and to search for such counterparts in additional objects. One new detection, the brightest knot in the NGC 6251 jet, is reported. In all cases, except part of the 3C 273 jet, the jet continua are well-represented by synchrotron spectra from truncated power-law electron distributions, with emitted-frame critical frequencies between 3 x 1014 and 2 x 1015 Hz. This may be due to fine structure in the jets or to the particle (re)acceleration process. Two hot spots (Pic A and 3C 303) differ from the jets, in showing unbroken power-law spectra from the radio to the B band. Image restoration has been used to examine the sub-arcsecond structure of the M87 jet and derive spectral shapes for various knots free of blending problems. The structure matches that seen in the radio to the Ol'S level, implying that the jet structure prevents particles from streaming freely over this distance (~30pc) Significant changes in turnover frequency occur from knot to knot, with an overall trend of higher frequency closer to the nucleus. Knot A is an exception, with a spectrum like the features near the core. An Appendix gives results of surface photometry for the program galaxies. -
A Fresh Insight Into the Evolutionary Status and Third Body Hypothesis of the Eclipsing Binaries AD Andromedae, AL Camelopardalis, and V338 Herculis
A&A 539, A129 (2012) Astronomy DOI: 10.1051/0004-6361/201117386 & c ESO 2012 Astrophysics A fresh insight into the evolutionary status and third body hypothesis of the eclipsing binaries AD Andromedae, AL Camelopardalis, and V338 Herculis A. Liakos1,P.Niarchos1, and E. Budding2,3 1 University of Athens, Department of Astrophysics, Astronomy and Mechanics, 157 84 Zografos, Athens, Greece e-mail: [alliakos;pniarcho]@phys.uoa.gr 2 Carter Observatory & School of Chemical and Physical Sciences, Victoria University, Wellington, New Zealand 3 Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand e-mail: [email protected] Received 1 June 2011 / Accepted 11 January 2012 ABSTRACT Aims. We aim to derive the absolute parameters of the components of AD And, AL Cam, and V338 Her, interpret their orbital period changes and discuss their evolutionary status. Methods. New and complete multi-filter light curves of the eclipsing binaries AD And, AL Cam, and V338 Her were obtained and analysed with modern methods. Using all reliably observed times of minimum light, we examined orbital period irregularities using the least squares method. In addition, we acquired new spectroscopic observations during the secondary eclipses for AL Cam and V338 Her. Results. For AL Cam and V338 Her, we derive reliable spectral types for their primary stars. Statistical checks of orbital period analysis for all systems are very reassuring in the cases of V338 Her and AD And, although less so for AL Cam. The LIght-Time Effect (LITE) results are checked by inclusion of a third light option in the photometric analyses. -
134, December 2007
British Astronomical Association VARIABLE STAR SECTION CIRCULAR No 134, December 2007 Contents AB Andromedae Primary Minima ......................................... inside front cover From the Director ............................................................................................. 1 Recurrent Objects Programme and Long Term Polar Programme News............4 Eclipsing Binary News ..................................................................................... 5 Chart News ...................................................................................................... 7 CE Lyncis ......................................................................................................... 9 New Chart for CE and SV Lyncis ........................................................ 10 SV Lyncis Light Curves 1971-2007 ............................................................... 11 An Introduction to Measuring Variable Stars using a CCD Camera..............13 Cataclysmic Variables-Some Recent Experiences ........................................... 16 The UK Virtual Observatory ......................................................................... 18 A New Infrared Variable in Scutum ................................................................ 22 The Life and Times of Charles Frederick Butterworth, FRAS........................24 A Hard Day’s Night: Day-to-Day Photometry of Vega and Beta Lyrae.........28 Delta Cephei, 2007 ......................................................................................... 33 -
Three Naked Eye Galaxies? Dave Eagle
Three Naked Eye Galaxies? Dave Eagle. Eagleseye Observatory. Star hopping to M31, The Great Andromeda Galaxy. In the autumn sky in the northern hemisphere, the constellations of Perseus and Andromeda are very proudly on display, located on the meridian around midnight, and visible from most of the world. The Great Square of Pegasus is a distinct asterism of four stars. Using just your naked eye, find this square of stars. Incidentally, the top left star (all instructions are now as seen from the northern hemisphere) Sirrah, is now actually Alpha Andromedae. From this square of stars take the top edge of the square and carry the line on towards the left (east) and up. Just under half the distance of the top of the square, you should come to another reasonably bright star. Slightly left and up again, taking a slightly longer journey, you will come to another star of similar brightness. This is Mirach or Beta Andromedae. When you have found this star, turn 90 degrees to the right. You will then see two fairly bright stars leading away. Aim for the second star and gaze at this star. If your skies are reasonably dark, just above and to the right of the second star you should be able to see a faint smudge. This marks the location of M31, The Andromeda Galaxy. In five hops we have found our quarry. Figure 1 – Star hopping from Sirrah to The Andromeda Galaxy. This is the most distant object you can see with the naked eye and is almost 2.5 million light years away. -
Thesis, Anton Pannekoek Institute, Universiteit Van Amsterdam
UvA-DARE (Digital Academic Repository) The peculiar climates of ultra-hot Jupiters Arcangeli, J. Publication date 2020 Document Version Final published version License Other Link to publication Citation for published version (APA): Arcangeli, J. (2020). The peculiar climates of ultra-hot Jupiters. General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl) Download date:09 Oct 2021 Jacob Arcangeli of Ultra-hot Jupiters The peculiar climates The peculiar climates of Ultra-hot Jupiters Jacob Arcangeli The peculiar climates of Ultra-hot Jupiters Jacob Arcangeli © 2020, Jacob Arcangeli Contact: [email protected] The peculiar climates of Ultra-hot Jupiters Thesis, Anton Pannekoek Institute, Universiteit van Amsterdam Cover by Imogen Arcangeli ([email protected]) Printed by Amsterdam University Press ANTON PANNEKOEK INSTITUTE The research included in this thesis was carried out at the Anton Pannekoek Institute for Astronomy (API) of the University of Amsterdam. -
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. -
Jet-Powered Molecular Hydrogen Emission from Radio Galaxies
JET-POWERED MOLECULAR HYDROGEN EMISSION FROM RADIO GALAXIES The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Ogle, Patrick, Francois Boulanger, Pierre Guillard, Daniel A. Evans, Robert Antonucci, P. N. Appleton, Nicole Nesvadba, and Christian Leipski. “JET-POWERED MOLECULAR HYDROGEN EMISSION FROM RADIO GALAXIES.” The Astrophysical Journal 724, no. 2 (November 11, 2010): 1193–1217. © 2010 The American Astronomical Society As Published http://dx.doi.org/10.1088/0004-637x/724/2/1193 Publisher IOP Publishing Version Final published version Citable link http://hdl.handle.net/1721.1/95698 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The Astrophysical Journal, 724:1193–1217, 2010 December 1 doi:10.1088/0004-637X/724/2/1193 C 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A. JET-POWERED MOLECULAR HYDROGEN EMISSION FROM RADIO GALAXIES Patrick Ogle1, Francois Boulanger2, Pierre Guillard1, Daniel A. Evans3, Robert Antonucci4, P. N. Appleton5, Nicole Nesvadba2, and Christian Leipski6 1 Spitzer Science Center, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125, USA; [email protected] 2 Institut d’Astrophysique Spatiale, Universite Paris-Sud 11, Bat. 121, 91405 Orsay Cedex, France 3 MIT Center for Space Research, Cambridge, MA 02139, USA 4 Physics Department, University of California, Santa Barbara, CA 93106, USA 5 NASA Herschel Science Center, California Institute of Technology, Mail Code 100-22, Pasadena, CA 91125, USA 6 Max-Planck Institut fur¨ Astronomie (MPIA), Konigstuhl¨ 17, D-69117 Heidelberg, Germany Received 2009 November 10; accepted 2010 September 22; published 2010 November 11 ABSTRACT H2 pure-rotational emission lines are detected from warm (100–1500 K) molecular gas in 17/55 (31% of) radio galaxies at redshift z<0.22 observed with the Spitzer IR Spectrograph.