An Astrophysical Laboratory: Understanding and Exploiting the Young Massive Cluster Westerlund 1
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Astronomie in Theorie Und Praxis 8. Auflage in Zwei Bänden Erik Wischnewski
Astronomie in Theorie und Praxis 8. Auflage in zwei Bänden Erik Wischnewski Inhaltsverzeichnis 1 Beobachtungen mit bloßem Auge 37 Motivation 37 Hilfsmittel 38 Drehbare Sternkarte Bücher und Atlanten Kataloge Planetariumssoftware Elektronischer Almanach Sternkarten 39 2 Atmosphäre der Erde 49 Aufbau 49 Atmosphärische Fenster 51 Warum der Himmel blau ist? 52 Extinktion 52 Extinktionsgleichung Photometrie Refraktion 55 Szintillationsrauschen 56 Angaben zur Beobachtung 57 Durchsicht Himmelshelligkeit Luftunruhe Beispiel einer Notiz Taupunkt 59 Solar-terrestrische Beziehungen 60 Klassifizierung der Flares Korrelation zur Fleckenrelativzahl Luftleuchten 62 Polarlichter 63 Nachtleuchtende Wolken 64 Haloerscheinungen 67 Formen Häufigkeit Beobachtung Photographie Grüner Strahl 69 Zodiakallicht 71 Dämmerung 72 Definition Purpurlicht Gegendämmerung Venusgürtel Erdschattenbogen 3 Optische Teleskope 75 Fernrohrtypen 76 Refraktoren Reflektoren Fokus Optische Fehler 82 Farbfehler Kugelgestaltsfehler Bildfeldwölbung Koma Astigmatismus Verzeichnung Bildverzerrungen Helligkeitsinhomogenität Objektive 86 Linsenobjektive Spiegelobjektive Vergütung Optische Qualitätsprüfung RC-Wert RGB-Chromasietest Okulare 97 Zusatzoptiken 100 Barlow-Linse Shapley-Linse Flattener Spezialokulare Spektroskopie Herschel-Prisma Fabry-Pérot-Interferometer Vergrößerung 103 Welche Vergrößerung ist die Beste? Blickfeld 105 Lichtstärke 106 Kontrast Dämmerungszahl Auflösungsvermögen 108 Strehl-Zahl Luftunruhe (Seeing) 112 Tubusseeing Kuppelseeing Gebäudeseeing Montierungen 113 Nachführfehler -
Rosette Nebula and Monoceros Loop
Oshkosh Scholar Page 43 Studying Complex Star-Forming Fields: Rosette Nebula and Monoceros Loop Chris Hathaway and Anthony Kuchera, co-authors Dr. Nadia Kaltcheva, Physics and Astronomy, faculty adviser Christopher Hathaway obtained a B.S. in physics in 2007 and is currently pursuing his masters in physics education at UW Oshkosh. He collaborated with Dr. Nadia Kaltcheva on his senior research project and presented their findings at theAmerican Astronomical Society meeting (2008), the Celebration of Scholarship at UW Oshkosh (2009), and the National Conference on Undergraduate Research in La Crosse, Wisconsin (2009). Anthony Kuchera graduated from UW Oshkosh in May 2008 with a B.S. in physics. He collaborated with Dr. Kaltcheva from fall 2006 through graduation. He presented his astronomy-related research at Posters in the Rotunda (2007 and 2008), the Wisconsin Space Conference (2007), the UW System Symposium for Undergraduate Research and Creative Activity (2007 and 2008), and the American Astronomical Society’s 211th meeting (2008). In December 2009 he earned an M.S. in physics from Florida State University where he is currently working toward a Ph.D. in experimental nuclear physics. Dr. Nadia Kaltcheva is a professor of physics and astronomy. She received her Ph.D. from the University of Sofia in Bulgaria. She joined the UW Oshkosh Physics and Astronomy Department in 2001. Her research interests are in the field of stellar photometry and its application to the study of Galactic star-forming fields and the spiral structure of the Milky Way. Abstract An investigation that presents a new analysis of the structure of the Northern Monoceros field was recently completed at the Department of Physics andAstronomy at UW Oshkosh. -
Star Clusters
Star Clusters • Eventually, photons and stellar winds clear out the remaining gas and dust and leave behind the stars. • Reflection nebulae provide evidence for remaining dust on the far side of the Pleiades Star Clusters • It may be that all stars are born in clusters. • A good question is therefore why are most stars we see in the Galaxy not members of obvious clusters? • The answer is that the majority of newly-formed clusters are very weakly gravitationally bound. Perturbations from passing molecular clouds, spiral arms or mass loss from the cluster stars `unbind’ most clusters. Star Cluster Ages • We can use the H-R Diagram of the stars in a cluster to determine the age of the cluster. • A cluster starts off with stars along the full main sequence. • Because stars with larger mass evolve more quickly, the hot, luminous end of the main sequence becomes depleted with time. • The `main-sequence turnoff’ moves to progressively lower mass, L and T with time. • Young clusters contain short-lived, massive stars in their main sequence • Other clusters are missing the high-mass MSTO stars and we can infer the cluster age is the main-sequence lifetime of the highest mass star still on the main- sequence. 25Mo 3million years 104 3Mo 500Myrs 102 1M 10Gyr L o 1 0.5Mo 200Gyr 10-2 30000 15000 7500 3750 Temperature Star Clusters Sidetrip • There are two basic types of clusters in the Galaxy. • Globular Clusters are mostly in the halo of the Galaxy, contain >100,000 stars and are very ancient. • Open clusters are in the disk, contain between several and a few thousand stars and range in age from 0 to 10Gyr Galaxy Ages • Deriving galaxy ages is much harder because most galaxies have a star formation history rather than a single-age population of stars. -
The Young Stellar Population of IC 1613 III
A&A 551, A74 (2013) Astronomy DOI: 10.1051/0004-6361/201219977 & c ESO 2013 Astrophysics The young stellar population of IC 1613 III. New O-type stars unveiled by GTC-OSIRIS,, M. Garcia1,2 and A. Herrero1,2 1 Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain e-mail: [email protected] 2 Departamento de Astrofísica, Universidad de La Laguna, Avda. Astrofísico Francisco Sánchez, s/n, 38071 La Laguna, Tenerife, Spain Received 9 July 2012 / Accepted 16 November 2012 ABSTRACT Context. Very low-metallicity massive stars are key to understanding the reionization epoch. Radiation-driven winds, chief agents in the evolution of massive stars, are consequently an important ingredient in our models of the early-Universe. Recent findings hint that the winds of massive stars with poorer metallicity than the SMC may be stronger than predicted by theory. Besides calling the paradigm of radiation-driven winds into question, this result would affect the calculated ionizing radiation and mechanical feedback of massive stars, as well as the role these objects play at different stages of the Universe. Aims. The field needs a systematic study of the winds of a large sample of very metal-poor massive stars. The sampling of spectral types is particularly poor in the very early types. This paper’s goal is to increase the list of known O-type stars in the dwarf irregular galaxy IC 1613, whose metallicity is lower than the SMC’s roughly by a factor 2. Methods. Using the reddening-free Q pseudo-colour, evolutionary masses, and GALEX photometry, we built a list of very likely O-type stars. -
Pos(INTEGRAL 2010)091
A candidate former companion star to the Magnetar CXOU J164710.2-455216 in the massive Galactic cluster Westerlund 1 PoS(INTEGRAL 2010)091 P.J. Kavanagh 1 School of Physical Sciences and NCPST, Dublin City University Glasnevin, Dublin 9, Ireland E-mail: [email protected] E.J.A. Meurs School of Cosmic Physics, DIAS, and School of Physical Sciences, DCU Glasnevin, Dublin 9, Ireland E-mail: [email protected] L. Norci School of Physical Sciences and NCPST, Dublin City University Glasnevin, Dublin 9, Ireland E-mail: [email protected] Besides carrying the distinction of being the most massive young star cluster in our Galaxy, Westerlund 1 contains the notable Magnetar CXOU J164710.2-455216. While this is the only collapsed stellar remnant known for this cluster, a further ~10² Supernovae may have occurred on the basis of the cluster Initial Mass Function, possibly all leaving Black Holes. We identify a candidate former companion to the Magnetar in view of its high proper motion directed away from the Magnetar region, viz. the Luminous Blue Variable W243. We discuss the properties of W243 and how they pertain to the former Magnetar companion hypothesis. Binary evolution arguments are employed to derive a progenitor mass for the Magnetar of 24-25 M Sun , just within the progenitor mass range for Neutron Star birth. We also draw attention to another candidate to be member of a former massive binary. 8th INTEGRAL Workshop “The Restless Gamma-ray Universe” Dublin, Ireland September 27-30, 2010 1 Speaker Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. -
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. -
Supernova 2007Bi Was a Pair-Instability Explosion
Supernova 2007bi was a pair-instability explosion A. Gal-Yam, Benoziyo Center for Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100, Israel, P. Mazzali, Max-Planck-Institut f¨ur Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany, and Scuola Normale Superiore, Piazza Cavalieri 7, 56127 Pisa, Italy, E. O. Ofek, Department of Astronomy, 105-24, California Institute of Technology, Pasadena, CA 91125, USA, P. E. Nugent, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720-3411, USA, S. R. Kulkarni, M. M. Kasliwal, R. M. Quimby, Department of Astronomy, 105-24, California Institute of Technology, Pasadena, CA 91125, USA, A. V. Filippenko, S. B. Cenko, R. Chornock, Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA, R. Waldman, The Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel, D. Kasen, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA, M. Sullivan, Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH, UK, arXiv:1001.1156v1 [astro-ph.CO] 7 Jan 2010 E. C. Beshore, Department of Planetary Sciences, Lunar and Planetary Laboratory, 1629 E. University Blvd, Tucson AZ 85721, USA, A. J. Drake, Department of Astronomy, 105-24, California Institute of Technology, Pasadena, CA 91125, USA, R. C. Thomas, Luis W. Alvarez Fellow, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720-3411, USA, J. S. Bloom, D. Poznanski, A. A. Miller, Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA, R. J. Foley, Clay Fellow, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, J. -
Exors and the Stellar Birthline Mackenzie S
A&A 600, A133 (2017) Astronomy DOI: 10.1051/0004-6361/201630196 & c ESO 2017 Astrophysics EXors and the stellar birthline Mackenzie S. L. Moody1 and Steven W. Stahler2 1 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA e-mail: [email protected] 2 Astronomy Department, University of California, Berkeley, CA 94720, USA e-mail: [email protected] Received 6 December 2016 / Accepted 23 February 2017 ABSTRACT We assess the evolutionary status of EXors. These low-mass, pre-main-sequence stars repeatedly undergo sharp luminosity increases, each a year or so in duration. We place into the HR diagram all EXors that have documented quiescent luminosities and effective temperatures, and thus determine their masses and ages. Two alternate sets of pre-main-sequence tracks are used, and yield similar results. Roughly half of EXors are embedded objects, i.e., they appear observationally as Class I or flat-spectrum infrared sources. We find that these are relatively young and are located close to the stellar birthline in the HR diagram. Optically visible EXors, on the other hand, are situated well below the birthline. They have ages of several Myr, typical of classical T Tauri stars. Judging from the limited data at hand, we find no evidence that binarity companions trigger EXor eruptions; this issue merits further investigation. We draw several general conclusions. First, repetitive luminosity outbursts do not occur in all pre-main-sequence stars, and are not in themselves a sign of extreme youth. They persist, along with other signs of activity, in a relatively small subset of these objects. -
The Impact of the Astro2010 Recommendations on Variable Star Science
The Impact of the Astro2010 Recommendations on Variable Star Science Corresponding Authors Lucianne M. Walkowicz Department of Astronomy, University of California Berkeley [email protected] phone: (510) 642–6931 Andrew C. Becker Department of Astronomy, University of Washington [email protected] phone: (206) 685–0542 Authors Scott F. Anderson, Department of Astronomy, University of Washington Joshua S. Bloom, Department of Astronomy, University of California Berkeley Leonid Georgiev, Universidad Autonoma de Mexico Josh Grindlay, Harvard–Smithsonian Center for Astrophysics Steve Howell, National Optical Astronomy Observatory Knox Long, Space Telescope Science Institute Anjum Mukadam, Department of Astronomy, University of Washington Andrej Prsa,ˇ Villanova University Joshua Pepper, Villanova University Arne Rau, California Institute of Technology Branimir Sesar, Department of Astronomy, University of Washington Nicole Silvestri, Department of Astronomy, University of Washington Nathan Smith, Department of Astronomy, University of California Berkeley Keivan Stassun, Vanderbilt University Paula Szkody, Department of Astronomy, University of Washington Science Frontier Panels: Stars and Stellar Evolution (SSE) February 16, 2009 Abstract The next decade of survey astronomy has the potential to transform our knowledge of variable stars. Stellar variability underpins our knowledge of the cosmological distance ladder, and provides direct tests of stellar formation and evolution theory. Variable stars can also be used to probe the fundamental physics of gravity and degenerate material in ways that are otherwise impossible in the laboratory. The computational and engineering advances of the past decade have made large–scale, time–domain surveys an immediate reality. Some surveys proposed for the next decade promise to gather more data than in the prior cumulative history of astronomy. -
Star Formation in the “Gulf of Mexico”
A&A 528, A125 (2011) Astronomy DOI: 10.1051/0004-6361/200912671 & c ESO 2011 Astrophysics Star formation in the “Gulf of Mexico” T. Armond1,, B. Reipurth2,J.Bally3, and C. Aspin2, 1 SOAR Telescope, Casilla 603, La Serena, Chile e-mail: [email protected] 2 Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, Hilo, HI 96720, USA e-mail: [reipurth;caa]@ifa.hawaii.edu 3 Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309, USA e-mail: [email protected] Received 9 June 2009 / Accepted 6 February 2011 ABSTRACT We present an optical/infrared study of the dense molecular cloud, L935, dubbed “The Gulf of Mexico”, which separates the North America and the Pelican nebulae, and we demonstrate that this area is a very active star forming region. A wide-field imaging study with interference filters has revealed 35 new Herbig-Haro objects in the Gulf of Mexico. A grism survey has identified 41 Hα emission- line stars, 30 of them new. A small cluster of partly embedded pre-main sequence stars is located around the known LkHα 185-189 group of stars, which includes the recently erupting FUor HBC 722. Key words. Herbig-Haro objects – stars: formation 1. Introduction In a grism survey of the W80 region, Herbig (1958) detected a population of Hα emission-line stars, LkHα 131–195, mostly The North America nebula (NGC 7000) and the adjacent Pelican T Tauri stars, including the little group LkHα 185 to 189 located nebula (IC 5070), both well known for the characteristic shapes within the dark lane of the Gulf of Mexico, thus demonstrating that have given rise to their names, are part of the single large that low-mass star formation has recently taken place here. -
SXP 1062, a Young Be X-Ray Binary Pulsar with Long Spin Period⋆
A&A 537, L1 (2012) Astronomy DOI: 10.1051/0004-6361/201118369 & c ESO 2012 Astrophysics Letter to the Editor SXP 1062, a young Be X-ray binary pulsar with long spin period Implications for the neutron star birth spin F. Haberl1, R. Sturm1, M. D. Filipovic´2,W.Pietsch1, and E. J. Crawford2 1 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany e-mail: [email protected] 2 University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW1797, Australia Received 31 October 2011 / Accepted 1 December 2011 ABSTRACT Context. The Small Magellanic Cloud (SMC) is ideally suited to investigating the recent star formation history from X-ray source population studies. It harbours a large number of Be/X-ray binaries (Be stars with an accreting neutron star as companion), and the supernova remnants can be easily resolved with imaging X-ray instruments. Aims. We search for new supernova remnants in the SMC and in particular for composite remnants with a central X-ray source. Methods. We study the morphology of newly found candidate supernova remnants using radio, optical and X-ray images and inves- tigate their X-ray spectra. Results. Here we report on the discovery of the new supernova remnant around the recently discovered Be/X-ray binary pulsar CXO J012745.97−733256.5 = SXP 1062 in radio and X-ray images. The Be/X-ray binary system is found near the centre of the supernova remnant, which is located at the outer edge of the eastern wing of the SMC. The remnant is oxygen-rich, indicating that it developed from a type Ib event. -
Andrea Possenti
UniversidadUniversidad dede ValenciaValencia 1515November November2010 2010 PulsarsPulsars asas probesprobes forfor thethe existenceexistence ofof IMBHsIMBHs ANDREA POSSENTI LayoutLayout ¾¾ KnownKnown BlackBlack HoleHole classesclasses ¾¾ FormationFormation scenariosscenarios forfor thethe IMBHsIMBHs ¾¾ IMBHIMBH candidatescandidates ¾¾ IMBHIMBH candidatescandidates (?)(?) fromfrom RadioRadio PulsarPulsar datadata analysisanalysis ¾¾ PerspectivesPerspectives forfor thethe directdirect observationobservation ofof IMBHsIMBHs fromfrom PulsarPulsar searchessearches ClassesClasses ofof BlackBlack HolesHoles Stellar mass Black Holes resulting from star evolution are supposed to be contained in many X-ray binaries: for solar metallicity, the max mass is of order few 10 Msun Massive Black Holes seen in the nucleus of the galaxies: 6 9 masses of order ≈ 10 Msun to ≈ 10 Msun AreAre IntermediateIntermediate Mass Black Holes ((IMBH)IMBH) ofof massesmasses ≈≈ 100100 -- 10,000 10,000 MMsunsun alsoalso partpart ofof thethe astronomicalastronomical landscapelandscape ?? N.B. ULX in the Globular Cluster RZ2109 of NGC 4472 may be a stellar mass BH likely in a triple system [ Maccarone et al. 2007 - 2010 ] FormationFormation mechanismsmechanisms forfor IMBHsIMBHs 11- - Mass Mass segregationsegregation ofof compactcompact remnantsremnants inin aa densedense starstar cluster 22– – Runaway Runaway collisionscollisions ofof massivemassive starsstars inin aa densedense starstar clustercluster In both cases, the seed IMBH can then grow by capturing other “ordinary”