Spectropolarimetry As a Probe of Stellar Winds
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Rotating Wolf-Rayet Stars in a Post RSG/LBV Phase an Evolutionary Channel Towards Long-Duration Grbs?
A&A 547, A83 (2012) Astronomy DOI: 10.1051/0004-6361/201118664 & c ESO 2012 Astrophysics Rotating Wolf-Rayet stars in a post RSG/LBV phase An evolutionary channel towards long-duration GRBs? G. Gräfener1,J.S.Vink1, T. J. Harries2, and N. Langer3 1 Armagh Observatory, College Hill, Armagh BT61 9DG, UK 2 School of Physics and Astronomy, University of Exeter, Stocker Rd, Exeter EX4 4QL, UK 3 Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany Received 16 December 2011 / Accepted 3 October 2012 ABSTRACT Context. Wolf-Rayet (WR) stars with fast rotating cores are thought to be the direct progenitors of long-duration gamma-ray bursts (LGRBs). A well accepted evolutionary channel towards LGRBs is chemically-homogeneous evolution at low metallicities, which completely avoids a red supergiant (RSG), or luminous blue variable (LBV) phase. On the other hand, strong absorption features with velocities of several hundred km s−1 have been found in some LGRB afterglow spectra (GRB 020813 and GRB 021004), which have been attributed to dense circumstellar (CS) material that has been ejected in a previous RSG or LBV phase, and is interacting with a fast WR-type stellar wind. Aims. Here we investigate the properties of Galactic WR stars and their environment to identify similar evolutionary channels that may lead to the formation of LGRBs. Methods. We compile available information on the spectropolarimetric properties of 29 WR stars, the presence of CS ejecta for 172 WR stars, and the CS velocities in the environment of 34 WR stars in the Galaxy. -
X-Ray Emission from Wolf-Rayet Stars
X-ray Emission from Wolf-Rayet Stars Steve Skinner1, Svet Zhekov2, Manuel Güdel3 Werner Schmutz4, Kimberly Sokal1 1CASA, Univ. of Colorado (USA) [email protected] 2Space Research Inst. (Bulgaria) and JILA/Univ. of Colorado (USA) 3ETH Zurich (Switzerland) 3PMOD (Switzerland) Abstract We present an overview of recent X-ray observations of Wolf-Rayet (WR) stars with XMM-Newton and Chandra. Observations of several WC-type (carbon-rich) WR stars without known companions have yielded only non-detections, implying they are either very feeble X-ray emitters or perhaps even X-ray quiet. In contrast, several apparently single WN2-6 stars have been detected, but data are sparse for later WN7-9 stars. Putatively single WN stars such as WR 134 have X-ray luminosities and spectra that are strikingly similar to some known WN + OB binaries such as WR 147, suggesting a similar emission mechanism. 1 X-rays from WR Stars: Overview 3 Single Nitrogen-rich WN Stars 4 Wolf-Rayet Binaries WR stars are the evolutionary descendants of massive O • Sensitive X-ray observations have now been obtained • High-resolution X-ray grating spectra have been ob- stars and are losing mass at very high rates. They are in ad- of several putatively single WN2-6 stars with XMM tained for a few binaries such as γ2 Vel (WC8 + vanced nuclear burning stages, approaching the end of their and Chandra. All but one were detected (Fig. 1). O7.5; Fig. 3) and WR 140 (WC7 + O4-5). CCD lives as supernovae. Strong X-rays have been detected from CCD spectra exist (Fig. -
A 2.4-12 Microns Spectrophotometric Study with ISO of Cygnus X-3 in Quiescence
1 Abstract. We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray bi- nary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4 - 12 µm continuum radiation observed with ISOPHOT-S can be explained by thermal free-free emis- sion in an expanding wind with, above 6.5 µm, a possi- ble additional black-body component with temperature T ∼ 250K and radius R ∼ 5000R⊙ at 10 kpc, likely due to thermal emission by circumstellar dust. The observed brightness and continuum spectrum closely match that of the Wolf-Rayet star WR 147, a WN8+B0.5 binary system, when rescaled at the same 10 kpc distance as Cygnus X- 3. A rough mass loss estimate assuming a WN wind gives −4 −1 ∼ 1.2 × 10 M⊙.yr . A line at ∼ 4.3 µm with a more than 4.3 σ detection level, and with a dereddened flux of 126 mJy, is interpreted as the expected He I 3p-3s line at 4.295 µm, a prominent line in the WR 147 spectrum. These results are consistent with a Wolf-Rayet-like com- panion to the compact object in Cyg X-3 of WN8 type, a later type than suggested by earlier works. Key words: binaries: close - stars: individual: Cyg X-3 - stars: Wolf-Rayet - stars: mass loss - infrared: stars arXiv:astro-ph/0207466v1 22 Jul 2002 A&A manuscript no. ASTRONOMY (will be inserted by hand later) AND Your thesaurus codes are: missing; you have not inserted them ASTROPHYSICS A 2.4 - 12 µm spectrophotometric study with ISO of CygnusX-3 in quiescence ⋆ Lydie Koch-Miramond1, P´eter Abrah´am´ 2,3, Ya¨el Fuchs1,4, Jean-Marc Bonnet-Bidaud1, and Arnaud Claret1 1 DAPNIA/Service d’Astrophysique, CEA-Saclay, 91191 Gif-sur-Yvette Cedex, France 2 Konkoly Observatory, P.O. -
The Results of the 2013 Pro-Am Wolf-Rayet Campaign E
Wolf-Rayet Stars W.-R. Hamann, A. Sander, H. Todt, eds. Potsdam: Univ.-Verlag, 2015 URL: http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-84268 The Results of the 2013 Pro-Am Wolf-Rayet Campaign E. J. Aldoretta1, N. St-Louis1, N. D. Richardson1, A. F. J. Moffat1, T. Eversberg2, G. M. Hill3 and the World-Wide WR Pro-Am Campaign Team4;5 1Universite´ de Montr´eal, Canada 2Schn¨orringenTelescope Science Institute, Germany 3W. M. Keck Observatory, United States 4VdS Section Spectroscopy, Germany 5Astronomical Ring for Access to Spectroscopy (ARAS), France Professional and amateur astronomers around the world contributed to a 4-month long cam- paign in 2013, mainly in spectroscopy but also in photometry, interferometry and polarimetry, to observe the first 3 Wolf-Rayet stars discovered: WR 134 (WN6b), WR 135 (WC8) and WR 137 (WC7pd+O9). Each of these stars are interesting in their own way, showing a variety of stellar wind structures. The spectroscopic data from this campaign were reduced and analyzed for WR 134 in order to better understand its behavior and long-term periodicity in the context of CIRs in the wind. We will be presenting the results of these spectroscopic data, which include the confirmation of the CIR variability and a time-coherency of 40 days (half-life of 20 days). ∼ ∼ 1 Motivation and Campaign the spectral lines (Morel et al. 1999), WR 135 is known to show large clumpy structures in its wind Overview (Lepine et al. 1996) and WR 137 is a long-period WR+O binary system with possible CIRs (Lef`evre Co-rotating interaction regions (CIRs) form in the et al. -
Interstellarum 89 | August/September 2013 Fokussiert
interstellarum 89 | August/September 2013 fokussiert Titelbild: IC 410 im Schmalbandfilter-Komposit, umgesetzt als Falschfarbenaufnahme nach der Hubble-Palette. Aufgenommen mit einem 300/1140-Newton und Korrektor, Moravian Instruments G2 8300 CCD-Kamera, 10×8min (Hα), 11×8min ([OIII]), 11×8min ([SII]). Lesen Sie dazu mehr ab Seite 42. Thomas Jäger INTERAKTIV Werden Sie Follower des neuen interstellarum Twitter-Dienstes! . Die gesamte Redaktion informiert t g Sie täglich über Neuigkeiten aus der (Amateur-)Astronomie. www.twitter.com/interstellarum ist untersa g BUCHTIPP reitun Liebe Leserinnen, liebe Leser, b ein Sternatlas der neuen Generation – das ist der neue »interstellarum Deep-Sky- interstellarum Erscheint Deep-Sky-Atlas Atlas«, der am 1. September erscheinen wird. Über zehn Jahre habe ich an diesem neuen am 1.9. Ronald Stoyan, Konzept gearbeitet: ein Kartenwerk, das Deep-Sky-Objekte nicht einfach als Symbole Stephan Schurig darstellt, sondern diese so gestaltet, dass helle Objekte auf einen Blick von schwachen zu unterscheiden sind; ein Kartenwerk, das so einfach und logisch aufgebaut ist, dass auch unter schwierigen Bedingungen die Orientierung leicht fällt; ein Kartenwerk, das mit vielen kleinen Details von visuellen Objektumrissen bis zur Filterempfehlung auf die Bedürfnisse des praktischen Deep-Sky-Beobachters eingeht. Ich möchte Sie herzlich einladen, sich unter www.deepskyatlas.de über unser größtes Projekt in der Geschichte des Oculum-Verlags zu informieren, und den Atlas auf der Astromesse in Villingen- Schwenningen am 14. September selbst in Augenschein zu nehmen (Seite 2). Die Astromesse AME wird auch der Höhepunkt in unserem großen Astrofotowett- bewerb »Astrofotograf des Jahres 2013« sein. Nachdem die Jury aus den Astrofotografen Bernhard Hubl, Johannes Schedler, Ranga Yogeshwar sowie Egon Döberl von unserem nur zu privaten Zwecken. -
Annual Report / Rapport Annuel / Jahresbericht 1996
Annual Report / Rapport annuel / Jahresbericht 1996 ✦ ✦ ✦ E U R O P E A N S O U T H E R N O B S E R V A T O R Y ES O✦ 99 COVER COUVERTURE UMSCHLAG Beta Pictoris, as observed in scattered light Beta Pictoris, observée en lumière diffusée Beta Pictoris, im Streulicht bei 1,25 µm (J- at 1.25 microns (J band) with the ESO à 1,25 microns (bande J) avec le système Band) beobachtet mit dem adaptiven opti- ADONIS adaptive optics system at the 3.6-m d’optique adaptative de l’ESO, ADONIS, au schen System ADONIS am ESO-3,6-m-Tele- telescope and the Observatoire de Grenoble télescope de 3,60 m et le coronographe de skop und dem Koronographen des Obser- coronograph. l’observatoire de Grenoble. vatoriums von Grenoble. The combination of high angular resolution La combinaison de haute résolution angu- Die Kombination von hoher Winkelauflö- (0.12 arcsec) and high dynamical range laire (0,12 arcsec) et de gamme dynamique sung (0,12 Bogensekunden) und hohem dy- (105) allows to image the disk to only 24 AU élevée (105) permet de reproduire le disque namischen Bereich (105) erlaubt es, die from the star. Inside 50 AU, the main plane jusqu’à seulement 24 UA de l’étoile. A Scheibe bis zu einem Abstand von nur 24 AE of the disk is inclined with respect to the l’intérieur de 50 UA, le plan principal du vom Stern abzubilden. Innerhalb von 50 AE outer part. Observers: J.-L. Beuzit, A.-M. -
Curriculum Vitae Stephan Robert Mccandliss
August 2015 Curriculum Vitae Stephan Robert McCandliss Research Professor - JHU [email protected] Johns Hopkins University tel: 410-516-5272 Department of Physics & Astronomy fax: 410-516-8260 Baltimore, Maryland 21218 http://www.pha.jhu.edu/~stephan Familial History 1955/09/07 Born Salinas California 1989/01/01 Married Ann Marie McCandliss (nee Selander) 1989/11/10 Daughter Rachel Pearl McCandliss 1992/05/26 Son Ian Frederick McCandliss Education 1988 Ph.D. Astrophysics University of Colorado, Boulder 1981 B.S. Physics University of Washington, Seattle 1981 B.S. Astronomy University of Washington, Seattle Work History 2015 – present Director, Center for Astrophysical Sciences Johns Hopkins University 2010 – present Research Professor Johns Hopkins University 2002 – 2010 Principal Research Scientist Johns Hopkins University 1994 – 2002 Research Scientist Johns Hopkins University 1988 – 1994 Associate Research Scientist Johns Hopkins University 1981 – 1988 Ph.D. Candidate University of Colorado, Boulder 1977 – 1981 Reader and Lab Assistant University of Washington, Seattle Primary Research Interests The ionization history of the universe. Spectral signatures of dust, molecules and atoms in astrophysical environments. Rapid-response space science missions and enabling low-cost access to space. Space-based astronomical instrumentation. Service 2013 HST Cycle 21 Proposal Review Panel 2011 NASA APRA/SAT UV/Vis Review Panel Chair 2011 NSF Astronomy Advanced Technology and Instrumentation Opt/IR Panel 2008 – present Astrophysics Sounding Rocket -
Université De Montréal Étude De L'étoile Wolf-Rayet Variable WR 46 Dans L'ultraviolet Lointain Et Les Rayons X Par Vince
Université de Montréal Étude de l’étoile Wolf-Rayet variable WR 46 dans l’ultraviolet lointain et les rayons X par Vincent Hénault-Brunet Département de physique Faculté des arts et des sciences Mémoire présenté à la Faculté des études supérieures en vue de l’obtention du grade de Maître ès sciences (M.Sc.) en physique Août, 2009 c Vincent Hénault-Brunet, 2009 ! Université de Montréal Faculté des études supérieures Ce mémoire intitulé: Étude de l’étoile Wolf-Rayet variable WR 46 dans l’ultraviolet lointain et les rayons X présenté par: Vincent Hénault-Brunet a été évalué par un jury composé des personnes suivantes: Pierre Bergeron, président-rapporteur Nicole St-Louis, directrice de recherche Claude Carignan, membre du jury Mémoire accepté le: 11 septembre 2009 i «Il me semble que ce qui est requis est un délicat équilibre entre deux tendances : celle qui nous pousse à scruter de manière inlassablement sceptique toutes les hypothèses qui nous sont soumises et celle qui nous invite à garder une grande ouverture aux idées nouvelles.» - Carl Sagan ii Sommaire L’étoile Wolf-Rayet WR 46 est connue pour sa variabilité complexe sur des échelles de temps relativement courtes de quelques heures et sur des échelles de temps plus longues de plusieurs mois. Des décalages périodiques mais intermittents en vitesse radiale ont déjà été observés dans ses raies d’émission optiques. Plusieurs périodes photométriques ont aussi été mesurées dans le passé. Des pulsations non-radiales, une modulation liée à la rotation rapide, ou encore la présence d’un compagnon de faible masse dont la présence reste à confirmer ont été proposées pour expliquer le comportement de l’étoile sur des échelles de temps de quelques heures. -
The Wolf-Rayet Counterpart of Cygnusx-3
AND Your thesaurus codes are: View metadata, citation and similar papers at core.ac.uk ASTROPHYSICSbrought to you by CORE 05(08.02.1; 08.09.2 Cygnus X-3; 08.23.2; 13.25.5) 19.4.1996 provided by CERN Document Server The Wolf-Rayet counterpart of Cygnus X-3? M.H. van Kerkwijk1,2, T.R. Geballe3, D.L. King4, M. van der Klis1, and J. van Paradijs1,5 1 Astronomical Institute “Anton Pannekoek”, University of Amsterdam, and Center for High-Energy Astrophysics (CHEAF), Kruislaan 403, 1098 SJ Amsterdam, The Netherlands 2 Department of Astronomy, California Institute of Technology, m.s. 105-24, Pasadena, CA 91125, USA 3 Joint Astronomy Centre, 665 Komohana Street, Hilo, HI 96720, USA 4 Royal Greenwich Observatory, Madingley Road, Cambridge CB3 0EZ, UK 5 Physics Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA Submitted 1995 September 9 Abstract. We present orbital-phase resolved I and K- 1. Introduction band spectroscopy of Cygnus X-3. All spectra show emis- sion lines characteristic of Wolf-Rayet stars of the WN Cygnus X-3 is a bright X-ray source that is peculiar among subclass. On time scales longer than about one day, the X-ray binaries. It has huge radio outbursts, mildly rela- line strengths show large changes, both in flux and in tivistic (β ' 0.3) jets, smooth 4.8 hour orbital modulation equivalent width. In addition, the line ratios change, cor- of its X-ray light curve, and a rapid increase of the or- responding to a variation in spectral subtype of WN6/7 bital period on a time scale of 850 000 years. -
Cygnus X-3 and the Problem of the Missing Wolf-Rayet X-Ray Binaries
A&A 443, 231–241 (2005) Astronomy DOI: 10.1051/0004-6361:20052824 & c ESO 2005 Astrophysics Cygnus X-3 and the problem of the missing Wolf-Rayet X-ray binaries D. Lommen1,2, L. Yungelson1,3,4,E.vandenHeuvel1, G. Nelemans5, and S. Portegies Zwart1,6 1 Astronomical Institute “Anton Pannekoek”, University of Amsterdam, and Center for High Energy Astrophysics, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands e-mail: [email protected] 2 Sterrewacht Leiden, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands 3 Institute of Astronomy of the Russian Academy of Sciences, 48 Pyatniskaya Str., 119017 Moscow, Russia 4 Isaac Newton Institute, Moscow Branch, 12 Universitetskii Pr., Moscow, Russia 5 Astronomy Department, IMAPP, Radboud Universiteit Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands 6 Informatics Institute, University of Amsterdam, Kruislaan 403, 1098 SJ, Amsterdam, The Netherlands Received 6 February 2005 / Accepted 7 July 2005 ABSTRACT 38 −1 Cygnus X-3 is a strong X-ray source (LX ≈ 10 erg s ) which is thought to consist of a compact object accreting matter from a helium star. We analytically find that the estimated ranges of mass-loss rate and orbital-period derivative for Cyg X-3 are consistent with two models: i) the system is detached and the mass loss from the system comes from the stellar wind of a massive helium star, of which only a fraction that allows for the observed X-ray luminosity is accreted, or ii) the system is semidetached and a Roche-lobe-overflowing low- or moderate-mass helium donor transfers mass to the compact object, followed by ejection of its excess over the Eddington rate from the system. -
Thermodynamics and Statistical Mechanics
Thermodynamics and Statistical Mechanics Richard Fitzpatrick Professor of Physics The University of Texas at Austin Contents 1 Introduction 7 1.1 IntendedAudience.................................. 7 1.2 MajorSources.................................... 7 1.3 Why Study Thermodynamics? ........................... 7 1.4 AtomicTheoryofMatter.............................. 7 1.5 What is Thermodynamics? . ........................... 8 1.6 NeedforStatisticalApproach............................ 8 1.7 MicroscopicandMacroscopicSystems....................... 10 1.8 Classical and Statistical Thermodynamics . .................... 10 1.9 ClassicalandQuantumApproaches......................... 11 2 Probability Theory 13 2.1 Introduction . .................................. 13 2.2 What is Probability? . ........................... 13 2.3 Combining Probabilities . ........................... 13 2.4 Two-StateSystem.................................. 15 2.5 CombinatorialAnalysis............................... 16 2.6 Binomial Probability Distribution . .................... 17 2.7 Mean,Variance,andStandardDeviation...................... 18 2.8 Application to Binomial Probability Distribution . ................ 19 2.9 Gaussian Probability Distribution . .................... 22 2.10 CentralLimitTheorem............................... 25 Exercises ....................................... 26 3 Statistical Mechanics 29 3.1 Introduction . .................................. 29 3.2 SpecificationofStateofMany-ParticleSystem................... 29 2 CONTENTS 3.3 Principle -
Astronomy Magazine 2020 Index
Astronomy Magazine 2020 Index SUBJECT A AAVSO (American Association of Variable Star Observers), Spectroscopic Database (AVSpec), 2:15 Abell 21 (Medusa Nebula), 2:56, 59 Abell 85 (galaxy), 4:11 Abell 2384 (galaxy cluster), 9:12 Abell 3574 (galaxy cluster), 6:73 active galactic nuclei (AGNs). See black holes Aerojet Rocketdyne, 9:7 airglow, 6:73 al-Amal spaceprobe, 11:9 Aldebaran (Alpha Tauri) (star), binocular observation of, 1:62 Alnasl (Gamma Sagittarii) (optical double star), 8:68 Alpha Canum Venaticorum (Cor Caroli) (star), 4:66 Alpha Centauri A (star), 7:34–35 Alpha Centauri B (star), 7:34–35 Alpha Centauri (star system), 7:34 Alpha Orionis. See Betelgeuse (Alpha Orionis) Alpha Scorpii (Antares) (star), 7:68, 10:11 Alpha Tauri (Aldebaran) (star), binocular observation of, 1:62 amateur astronomy AAVSO Spectroscopic Database (AVSpec), 2:15 beginner’s guides, 3:66, 12:58 brown dwarfs discovered by citizen scientists, 12:13 discovery and observation of exoplanets, 6:54–57 mindful observation, 11:14 Planetary Society awards, 5:13 satellite tracking, 2:62 women in astronomy clubs, 8:66, 9:64 Amateur Telescope Makers of Boston (ATMoB), 8:66 American Association of Variable Star Observers (AAVSO), Spectroscopic Database (AVSpec), 2:15 Andromeda Galaxy (M31) binocular observations of, 12:60 consumption of dwarf galaxies, 2:11 images of, 3:72, 6:31 satellite galaxies, 11:62 Antares (Alpha Scorpii) (star), 7:68, 10:11 Antennae galaxies (NGC 4038 and NGC 4039), 3:28 Apollo missions commemorative postage stamps, 11:54–55 extravehicular activity