DOCSLIB.ORG

Sebastien GUILLOT Post-Doctoral Fellow at IRAP

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sebastien GUILLOT Post-Doctoral Fellow at IRAP Sebastien GUILLOT Post-doctoral Fellow at IRAP 9, avenue du Colonel Roche, BP 44346. 31028 Toulouse Cedex 4 [email protected] Citizenship: French Date of birth: August 6th, 1984 www.astro.puc.cl/~sguillot/ Research Interests Neutron stars, dense matter physics, High-energy phenomena, X-ray binaries and accretion physics, globular clusters Employment Institut de Recherche en Astrophysique et Planétologie, Toulouse, France 2018 CNES Post-doctoral Fellow Pontificia Universidad Católica de Chile, Instituto de Astrofísica 2015 – 2017 FONDECYT Post-doctoral Fellow McGill University, Physics Department 2014 – 2015 Post-doctoral researcher and outreach coordinator Education PhD in astrophysics, McGill University – Vanier Graduate Scholar 2014 Master in physics, McGill University 2009 Bachelor of Science (with distinctions), University of Victoria (BC, Canada) 2007 Euro-American Institute of Technology (EAI Tech, Sophia-Antipolis, France) 2001 – 2003 Note: Two-years preparation program in Astrophysics with courses in French/English, before transferring to UVic Other Research Experience Joint Institute for Laboratory Astrophysics, U. of Colorado (Supervisor: Rosalba Perna) 2013 Research Internship – 2 months, funded by FRQNT International Internship Award). Harvard-Smithsonian Centre for Astrophysics (Supervisor: Alyssa Goodman) 2006 Research Assistant with the COMPLETE team. Sub-mm observations of molecular clouds – 3 months. McGill University, Physics Department (Supervisor: Gil Holder) 2005 Research Assistant. Theoretical Cosmology (weak gravitational lensing) – 4 months. IAP, Institut d'Astrophysique de Paris (Supervisor: François Bouchet) 2005 Research Assistant with Planck-HFI Satellite Data Processing Center team – 4 months. IAS, Institut d'Astrophysique Spatiale, Orsay, France (Supervisor: François Pajot) 2004 Research Assistant with the Planck-HFI Satellite Calibration team – 4 months. Participation in International Observatory Collaborations Member of the “Extreme physics and compact objects” working group of X-ray Surveyor (to be proposed) Since 2016 Member of the “End points of stellar evolution” working group of the ATHENA+ X-Ray Observatory Since 2015 Member of three working groups of the NICER Mission Since 2015 Member of the “Magnetars and rotating radio pulsars” working group of the NuSTAR Observatory Since 2014 Observational Experience and Proposals PI on VLT program “The H-alpha disk emission from compact binaires in the cluster NGC 6397” (1.5 h) 2017 PI on VLT program “Constraining the neutron star EoS with the qLMXB in the globular cluster ωCen” (1.0 h) 2017 PI on Chandra program “Globular cluster neutron stars and the dense matter Equation of State” (83 hours) 2016 PI on VLT program “Constraining the neutron star EoS with the qLMXB in the globular cluster ωCen” (1.5 h) 2016 Observing at Magellan Clay Telescope with LDSS3 instrument (1 night) 2016 Observing at SOAR Telescope with Goodman Spectrograph (2 nights) 2016 Co-I on XMM-Newton program “Searching for thermal X-ray emission from pulsars to constrain the EoS” (13 h) 2015 Co-I (but main writer) on Chandra program “qLMXBs and CVs in the globular cluster NGV 6304” (28 h) 2010 Co-I (but main writer) on Gemini South program “Radial velocity measurement of LMXBs in NGC 6304” (12 h) 2009 Attendee at “1st Summer School on Multi-wavelength Astronomy” (EC program ITN 215212) 2009 Main Grants, Fellowships, and Scholarships ECOS-CONICYT France-Chile collaboration grant (as Co-I, but main writer and collaboration lead) 2017 Chandra observing grant (equivalent to ~ 40,000 € for US-based Co-Is) 2016 FONDECYT Post-doctoral Fellowship (3 years, equivalent to 110,000 €) 2015 Vanier Canada Graduate Scholarship (3 years, equivalent to 105,000 €) 2011 McGill Graduate Office Dow-Hickson Fellowship (equivalent to 5,000 €) 2010 Other Scholarships, Awards, and Honorific Memberships European Commission AHEAD Visitor programme 2017 European Commission AHEAD Trans-National Access to X-ray Data-Analysis travel grant 2016 McGill Scarlet Key Society Award and Membership Since 2013 International Internship Award, Fonds de Recherche du Québec: Nature and Technology (FRQNT) 2013 McGill Physics Department GREAT Travel Award (3 occurrences) 2012, 2013, 2014 McGill Graduate Travel Funding Award (3 occurrences) 2011, 2012, 2013 McGill Graduate Office Provost Graduate Fellowship 2009 Rutherford Physics Department Principal’s Graduate Fellowship 2008 McGill Graduate Office Recruitment Excellence Fellowship 2007 Victoria Center of the Royal Astronomical Society of Canada Price 2007 University of Victoria Physics Department Scholarship 2006 Euro-American Institute of Technology Best GPA Scholarship 2002 Teaching Experience Participation in the development of a teacher training workshop in science education (“Teacher Inquiry Institute”) 2015 Guest lecturer for the course “The Milky Way inside and Out”, at McGill University. 2015 Participation in astronomy course development at McGill Physics Department (astronomy laboratory) 2013 – 2014 Certificate from the T-PULSE Tomlinson University-Level Science Education workshop at McGill 2013 Laboratory Coordinator – Introductory physics course (~700 students) 2008 – 2012 Laboratory Instructor – Introductory physics course 2007 – 2008 Student Supervision and Mentorship Maud Thepenier – M.Sc. student at Université de Toulouse 2018 Goran Doll Carriel – B.Sc. Student at Pontificia Católica Universidad de Chile 2017– 2018 Rodrigo Moraga Merino – B.Sc. Student at Pontificia Católica Universidad de Chile 2017 Nicolas Baillot d’Etivaux – PhD Student at Université de Lyon / IPNL 2016 – 2018 Cristobal Reyes Muñoz – B.Sc. Student at Pontificia Católica Universidad de Chile 2015 – 2017 José Rafael Fentes – M.Sc. Student at Pontificia Católica Universidad de Chile 2016 Manuel Pichardo Marcano – M.Sc. Internship Student at IRAP, Toulouse, France (now PhD at Texas Tech) 2016 Outreach Experience Participation in the Fermi MasterClass Chile 2016 2016 Successful IAU Grant Proposal (ref.: OAD TF2-2015B-1345-AAAP, 2730 euros) 2015 Scientific consultant to a team primary school teachers as part of “Eclairs de Sciences” programme 2012 – 2015 Astronomy Ambassador of the American Astronomical Society Since 2013 Co-founder and coordinator of AstroMcGill, the astronomy outreach program at McGill University Since 2012 Host of over 40 AstroMcGill Podcasts Since 2012 Host of numerous observing events (night sky and solar observing) Since 2012 Facilitator and presenter of numerous astronomy activities in primary/secondary schools Since 2012 Numerous newspapers (La Presse, McGill Reporter), radio (Radio Canada, CBC Montreal Radio), and 2012 – 2015 TV interviews (CBC National, RDI, CTV Montreal) about the Transit of Venus, landing of ESA’s Philae Public Lectures “Les étoiles à neutrons: bien plus fascinantes que les trous noirs”, for the Societé d’Astronomie de Toulouse 2016 “Neutron Stars – More awesome than black-holes”, AstroMcGill Public Lecture (~200 attendees) 2015 “Are we there yet? Climbing the rungs of the distance ladder”, AstroMcGill Public Lecture (~80 attendees) 2015 “The Supernova 2014J”, for the McGill University Student Astronomy Club 2014 “What do we learn by studying the Cosmos?”, for the McGill University Student Astronomy Club 2013 “What do we learn by studying the Cosmos?”, at the Cummings Community Center (Montreal) 2013 Academic Responsibilities Peer-review work: Referee for A&A, ApJ, MNRAS, Time Allocation Committee for Gemini Observatory and NuSTAR Telescope Evaluation of research project for the Argentinian Commission of Sciences FONCyT LOC member of workshop “Treasures hidden in High-energy Catalogs”, to be held at IRAP (Toulouse) 2018 Co-organizer of daily astro-ph discussion group at the Instituto de Astrofisica, PUC 2017 McGill Space Institute Coordinator (interim) 2014 – 2015 Membre of the Scientific Council of the Centre de Recherche en Astrophysique du Québec (CRAQ) 2010 – 2014 Assistant organizer of two annual meetings of the CRAQ (~80 attendees) 2011 and 2014 Public relation officer of the astrophysics group at McGill University 2012 – 2013 President of the McGill Graduate Association of Physics Students 2010 – 2012 Lead organizer of the annual graduate student workshop of the CRAQ (~30 attendees) 2009 Languages Skills • French (first language) • English (fluent) • Spanish (fluent) • German (basics) Sebastien GUILLOT Post-doctoral Fellow at IRAP List of publications and other contributions h-index 8; 445 citations List of Refereed Publications (8 as first author) 1) “NICER observes the effects of an X-ray bursts on the accretion environment in Aquila X-1”, Laurens Keek, Zaven Arzoumanian, Peter Bult, Edward M. Cackett, Deepto Chakrabarty, Jérôme Chenevez, Andrew C. Fabian, Sebastien Guillot, Tolga Güver, et al. January 2018, Submitted to ApJ Letters. 2) “Dense matter with eXTP - White paper in support of the mission concept of the Extended X-ray Timing Polarimetry mission”, Anna Watts, WenFei Yu, Juri Poutanen, Shu Zhang, Alessandro Patruno, …, Sebastien Guillot, et al. December 2017, Submitted to Science China Journal. 3) “Old but still warm: Far-UV detection of PSR B0950+08”, George G. Pavlov, Blagoy Rangelov, Oleg Kargaltsev, Andreas Reisenegger, Sebastien Guillot, Cristobal Reyes, November 2017, ApJ, vol. 850, 79P. 4) “Thermal X-ray emission identified from the millisecond pulsar PSR J1909-3744”, Natalie A. Webb, Denis Leahy, Nicolas Baillot d’Etivaux, Didier Barret, Lucas Guillemot, Sebastien Guillot, Jérôme Margueron, Coleman Miller, October
Load more

Recommended publications
  • 5. Cosmic Distance Ladder Ii: Standard Candles
    5. COSMIC DISTANCE LADDER II: STANDARD CANDLES EQUIPMENT Computer with internet connection GOALS In this lab, you will learn: 1. How to use RR Lyrae variable stars to measures distances to objects within the Milky Way galaxy. 2. How to use Cepheid variable stars to measure distances to nearby galaxies. 3. How to use Type Ia supernovae to measure distances to faraway galaxies. 1 BACKGROUND A. MAGNITUDES Astronomers use apparent magnitudes , which are often referred to simply as magnitudes, to measure brightness: The more negative the magnitude, the brighter the object. The more positive the magnitude, the fainter the object. In the following tutorial, you will learn how to measure, or photometer , uncalibrated magnitudes: http://skynet.unc.edu/ASTR101L/videos/photometry/ 2 In Afterglow, go to “File”, “Open Image(s)”, “Sample Images”, “Astro 101 Lab”, “Lab 5 – Standard Candles”, “CD-47” and open the image “CD-47 8676”. Measure the uncalibrated magnitude of star A: uncalibrated magnitude of star A: ____________________ Uncalibrated magnitudes are always off by a constant and this constant varies from image to image, depending on observing conditions among other things. To calibrate an uncalibrated magnitude, one must first measure this constant, which we do by photometering a reference star of known magnitude: uncalibrated magnitude of reference star: ____________________ 3 The known, true magnitude of the reference star is 12.01. Calculate the correction constant: correction constant = true magnitude of reference star – uncalibrated magnitude of reference star correction constant: ____________________ Finally, calibrate the uncalibrated magnitude of star A by adding the correction constant to it: calibrated magnitude = uncalibrated magnitude + correction constant calibrated magnitude of star A: ____________________ The true magnitude of star A is 13.74.
    [Show full text]
  • New Globular Cluster Age Estimates and Constraints on the Cosmic Equation of State and the Matter Density of the Universe
    1 New Globular Cluster Age Estimates and Constraints on the Cosmic Equation of State and The Matter Density of the Universe. Lawrence M. Krauss* & Brian Chaboyer *Departments of Physics and Astronomy, Case Western Reserve University, 10900 Euclid Ave., Cleveland OH USA 44106-7079; Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH. USA New estimates of globular cluster distances, combined with revised ranges for input parameters in stellar evolution codes and recent estimates of the earliest redshift of cluster formation allow us to derive a new 95% confidence level lower limit on the age of the Universe of 11 Gyr. This is now definitively inconsistent with the expansion age for a flat Universe for the currently allowed range of the Hubble constant unless the cosmic equation of state is dominated by a component that violates the strong energy condition. This solidifies the case for a dark energy-dominated universe, complementing supernova data and direct measurements of the geometry and matter density in the Universe. The best-fit age is consistent with a cosmological constant-dominated (w=pressure/energy density = -1) universe. For the Hubble Key project best fit value of the Hubble Ω Constant our age limits yields the constraints w < -0.4 and Ωmatter < 0.38 at the 68 Ω % confidence level, and w < -0.26 and Ωmatter < 0.58 at the 95 % confidence level. Age determinations of globular clusters provided one of the earliest motivations for considering the possible existence of a cosmological constant. By comparing a lower limit on the age of the oldest globular clusters in our galaxy--- estimated in the 1980 s to be 15-20 Gyr---with the expansion age, determined by measurements of the Hubble constant, an apparent inconsistency arose: globular clusters appeared to be older than 2 the Universe unless one allowed for a possible Cosmological Constant.
    [Show full text]
  • The Ellipticities of Globular Clusters in the Andromeda Galaxy
    ASTRONOMY & ASTROPHYSICS MAY I 1996, PAGE 447 SUPPLEMENT SERIES Astron. Astrophys. Suppl. Ser. 116, 447-461 (1996) The ellipticities of globular clusters in the Andromeda galaxy A. Staneva1, N. Spassova2 and V. Golev1 1 Department of Astronomy, Faculty of Physics, St. Kliment Okhridski University of Sofia, 5 James Bourchier street, BG-1126 Sofia, Bulgaria 2 Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tsarigradsko chauss´ee, BG-1784 Sofia, Bulgaria Received March 15; accepted October 4, 1995 Abstract. — The projected ellipticities and orientations of 173 globular clusters in the Andromeda galaxy have been determined by using isodensity contours and 2D Gaussian fitting techniques. A number of B plates taken with the 2 m Ritchey-Chretien-coud´e reflector of the Bulgarian National Astronomical Observatory were digitized and processed for each cluster. The derived ellipticities and orientations are presented in the form of a catalogue?. The projected ellipticities of M 31 GCs lie between 0.03 0.24 with mean valueε ¯=0.086 0.038. It may be concluded that the most globular clusters in the Andromeda galaxy÷ are quite spherical. The derived± orientations do not show a preference with respect to the center of M 31. Some correlations of the ellipticity with other clusters parameters are discussed. The ellipticities determined in this work are compared with those in other Local Group galaxies. Key words: globular clusters: general — galaxies: individual: M 31 — galaxies: star clusters — catalogs 1. Introduction Bergh & Morbey (1984), and Kontizas et al. (1989), have shown that the globulars in LMC are markedly more ellip- Representing the oldest of all stellar populations, the glo- tical than those in our Galaxy.
    [Show full text]
  • The Cosmic Distance Scale • Distance Information Is Often Crucial to Understand the Physics of Astrophysical Objects
    The cosmic distance scale • Distance information is often crucial to understand the physics of astrophysical objects. This requires knowing the basic properties of such an object, like its size, its environment, its location in space... • There are essentially two ways to derive distances to astronomical objects, through absolute distance estimators or through relative distance estimators • Absolute distance estimators Objects for whose distance can be measured directly. They have physical properties which allow such a measurement. Examples are pulsating stars, supernovae atmospheres, gravitational lensing time delays from multiple quasar images, etc. • Relative distance estimators These (ultimately) depend on directly measured distances, and are based on the existence of types of objects that share the same intrinsic luminosity (and whose distance has been determined somehow). For example, there are types of stars that have all the same intrinsic luminosity. If the distance to a sample of these objects has been measured directly (e.g. through trigonometric parallax), then we can use these to determine the distance to a nearby galaxy by comparing their apparent brightness to those in the Milky Way. Essentially we use that log(D1/D2) = 1/5 * [(m1 –m2) - (A1 –A2)] where D1 is the distance to system 1, D2 is the distance to system 2, m1 is the apparent magnitudes of stars in S1 and S2 respectively, and A1 and A2 corrects for the absorption towards the sources in S1 and S2. Stars or objects which have the same intrinsic luminosity are known as standard candles. If the distance to such a standard candle has been measured directly, then the relative distances will have been anchored to an absolute distance scale.
    [Show full text]
  • Isolated Elliptical Galaxies and Their Globular Cluster Systems II
    A&A 574, A21 (2015) Astronomy DOI: 10.1051/0004-6361/201424530 & c ESO 2015 Astrophysics Isolated elliptical galaxies and their globular cluster systems II. NGC 7796 – globular clusters, dynamics, companion?;?? T. Richtler1;4, R. Salinas2, R. R. Lane1, M. Hilker4, and M. Schirmer3 1 Departamento de Astronomía, Universidad de Concepción, Concepción, Chile e-mail: [email protected] 2 Department of Physics and Astronomy, Michigan State University, 567 Wilson Road, MI 48824 East Lansing, USA 3 Gemini Observatory, Casilla 603, La Serena, Chile 4 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany Received 4 July 2014 / Accepted 16 November 2014 ABSTRACT Context. Rich globular cluster systems, particularly the metal-poor part of them, are thought to be the visible manifestations of long- term accretion processes. The invisible part is the dark matter halo, which may show some correspondence to the globular cluster system. It is therefore interesting to investigate the globular cluster systems of isolated elliptical galaxies, which supposedly have not experienced extended accretion. Aims. We investigate the globular cluster system of the isolated elliptical NGC 7796, present new photometry of the galaxy, and use published kinematical data to constrain the dark matter content. Methods. Deep images in B and R, obtained with the VIsible MultiObject Spectrograph (VIMOS) at the VLT, form the data base. We performed photometry with DAOPHOT and constructed a spherical photometric model. We present isotropic and anisotropic Jeans-models and give a morphological description of the companion dwarf galaxy. Results. The globular cluster system has about 2000 members, so it is not as rich as those of giant ellipticals in galaxy clusters with a comparable stellar mass, but richer than many cluster systems of other isolated ellipticals.
    [Show full text]
  • Globular Clusters
    Observing Globular Clusters TAAS Astronomy 101 Jon Schuchardt August 2016 Outline • What are globular clusters? • Historical significance • Shapley-Sawyer classification M5 (Serpens Caput) • How to find, observe, and report on globular clusters What are Globular Star Clusters? • Densely packed, spherical agglomerations of 104 to 107 very old stars (12-14 billion years old) that surround a galactic nucleus • Most in the Milky Way are 10,000 to 50,000 light years away from us • Diameters: 10s to 100s of light years • Densities: average about 1 star per cubic light year, but more dense in the core • About 150 globular clusters known in the Milky Way What are Globular Star Clusters? • Some globular clusters, e.g., M15, have undergone gravitational collapse in their cores • Glob cores can be millions or even billions of times more densely populated than our solar neighborhood • Imagine a night sky with thousands of stars brighter than Sirius! • Black holes of low stellar mass (10-20 solar masses) may be common at the center of globular clusters. They have been detected (2012-2013) in M22 (a pair) and M62 by detecting radio emissions using the Very Large Array M62 (Ophiuchus) Easier to “see” the black holes using radio emissions and the VLA versus a Hubble view of M22 (Sagittarius) J. Strader et al., Nature Oct 4, 2012 Hertzsprung-Russell diagrams: Typical globular cluster (left) and M55 (right) Note the “knee”” H-R Diagram for M3 (Canes Venatici) The “knee” shows where stars begin to depart the Main Sequence on their path to becoming giants Can be used to estimate the age of the cluster “The thing’s hollow -- it goes on forever -- and -- oh my God! -- it’s full of stars!” Commander David Bowman 2001: A Space Odyssey Arthur C.
    [Show full text]
  • High-Velocity Stars in the Cores of Globular Clusters: the Illustrative Case of NGC 2808
    A&A 543, A82 (2012) Astronomy DOI: 10.1051/0004-6361/201219062 & c ESO 2012 Astrophysics High-velocity stars in the cores of globular clusters: the illustrative case of NGC 2808 N. Lützgendorf1, A. Gualandris2,3, M. Kissler-Patig1,K.Gebhardt4,H.Baumgardt5, E. Noyola6, J. M. D. Kruijssen2, B. Jalali7,P.T.deZeeuw1,8, and N. Neumayer1 1 European Southern Observatory (ESO), Karl-Schwarzschild-Straße 2, 85748 Garching, Germany e-mail: [email protected] 2 Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Straße 1, 85748 Garching, Germany 3 Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK 4 Astronomy Department, University of Texas at Austin, Austin, TX 78712, USA 5 School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia 6 Instituto de Astronomia, Universidad Nacional Autonoma de Mexico (UNAM), A.P. 70-264, 04510 Mexico, Mexico 7 1. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany 8 Sterrewacht Leiden, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands Received 17 February 2012 / Accepted 15 May 2012 ABSTRACT Context. We report the detection of five high-velocity stars in the core of the globular cluster NGC 2808. The stars lie on the red giant −1 −1 branch and show total velocities between 40 and 45 km s . For a core velocity dispersion σc = 13.4kms , this corresponds to up −1 to 3.4σc. These velocities are close to the estimated escape velocity (∼50 km s ) and suggest an ejection from the core. Two of these stars have been confirmed in our recent integral field spectroscopy data and we will discuss them in more detail here.
    [Show full text]
  • Globular Cluster Ages
    Proc. Natl. Acad. Sci. USA Vol. 95, pp. 13–17, January 1998 Colloquium Paper This paper was presented at a colloquium entitled ‘‘The Age of the Universe, Dark Matter, and Structure Formation,’’ organized by David N. Schramm, held March 21–23, 1997, sponsored by the National Academy of Sciences at the Beckman Center in Irvine, CA. Globular cluster ages RAUL JIMENEZ* Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, United Kingdom ABSTRACT We review two new methods to determine the very useful technique to determine distances to GC indepen- age of globular clusters (GCs). These two methods are more dently of the subdwarf fitting and RR–Lyrae techniques. It is accurate than the classical isochrone fitting technique. The also very powerful to determine relative ages of GCs with little first method is based on the morphology of the horizontal error. branch and is independent of the distance modulus of the In the next sections I describe the traditional isochrone globular cluster. The second method uses a careful binning of fitting method and the HB morphology and LF methods. I the stellar luminosity function and determines simultaneously finish with a discussion on the uncertainties of the different the distance and age of the GC. We find that the oldest galactic methods and the most likely value for the age of the oldest 6 GCs have an age of 13.5 2 gigayears (Gyr). The absolute GCs. minimum age for the oldest GCs is 10.5 Gyr (with 99% confidence) and the maximum 16.0 Gyr (with 99% confi- The Isochrone Fitting Method dence).
    [Show full text]
  • Star Clusters E NCYCLOPEDIA of a STRONOMY and a STROPHYSICS
    Star Clusters E NCYCLOPEDIA OF A STRONOMY AND A STROPHYSICS Star Clusters the Galaxy can be used to derive the cluster distance, independently of parallax measurements. Even a small telescope shows obvious local concentrations Afinal category of clusters has recently been identified of stars scattered around the sky. These star clusters are based on observations with infrared detectors. These are not chance juxtapositions of unrelated stars. They are, the embedded clusters—star clusters still in the process of instead, physically associated groups of stars, moving formation, and still embedded in the clouds out of which together through the Galaxy. The stars in a cluster are they formed. Because it is possible to see through the dust held together either permanently or temporarily by their much better at infrared wavelengths than in the optical, mutual gravitational attraction. these clusters have suddenly become observable. The classic, and best known, example of a star cluster Star clusters are of considerable astrophysical impor- is the Pleiades, visible in the evening sky in early winter tance to probe models of stellar evolution and dynamics, (from the northern hemisphere) as a group of 7–10 stars explore the star formation process, calibrate the extragalac- (depending on one’s eyesight). More than 600 Pleiades tic distance scale and most importantly to measure the age members have been identified telescopically. and evolution of the Galaxy. Clusters are generally distinguished as being either Definition of a star cluster—cluster catalogs GALACTIC OPEN CLUSTERS or GLOBULAR CLUSTERS, corresponding Just what is a cluster? How many stars does it take to to their appearance as seen through a moderate-aperture make a cluster? Trumpler in 1930 defined open clusters telescope.
    [Show full text]
  • A Astronomical Terminology
    A Astronomical Terminology A:1 Introduction When we discover a new type of astronomical entity on an optical image of the sky or in a radio-astronomical record, we refer to it as a new object. It need not be a star. It might be a galaxy, a planet, or perhaps a cloud of interstellar matter. The word “object” is convenient because it allows us to discuss the entity before its true character is established. Astronomy seeks to provide an accurate description of all natural objects beyond the Earth’s atmosphere. From time to time the brightness of an object may change, or its color might become altered, or else it might go through some other kind of transition. We then talk about the occurrence of an event. Astrophysics attempts to explain the sequence of events that mark the evolution of astronomical objects. A great variety of different objects populate the Universe. Three of these concern us most immediately in everyday life: the Sun that lights our atmosphere during the day and establishes the moderate temperatures needed for the existence of life, the Earth that forms our habitat, and the Moon that occasionally lights the night sky. Fainter, but far more numerous, are the stars that we can only see after the Sun has set. The objects nearest to us in space comprise the Solar System. They form a grav- itationally bound group orbiting a common center of mass. The Sun is the one star that we can study in great detail and at close range. Ultimately it may reveal pre- cisely what nuclear processes take place in its center and just how a star derives its energy.
    [Show full text]
  • Astronomy Astrophysics
    A&A 415, 123–143 (2004) Astronomy DOI: 10.1051/0004-6361:20031448 & c ESO 2004 Astrophysics VLT spectroscopy of globular cluster systems? I. The photometric and spectroscopic data set??;??? T. H. Puzia1, M. Kissler-Patig2, D. Thomas3, C. Maraston3,R.P.Saglia1, R. Bender1,3, T. Richtler4, P. Goudfrooij5,andM.Hempel2 1 Sternwarte der Ludwig-Maximilians-Universit¨at, Scheinerstr. 1, 81679 M¨unchen, Germany e-mail: [email protected] 2 European Southern Observatory, 85749 Garching bei M¨unchen, Germany e-mail: [email protected] 3 Max-Planck-Institut f¨ur extraterrestrische Physik, Giessenbachstrasse, 85748 Garching bei M¨unchen, Germany e-mail: bender, maraston, [email protected] 4 Grupo de Astronom´ıa, Departamento de F´ısica, Casilla 160-C, Universidad de Concepci´on, Concepci´on, Chile e-mail: [email protected] 5 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA e-mail: [email protected] Received 14 May 2003 / Accepted 11 September 2003 Abstract. We present Lick line-index measurements of extragalactic globular clusters in seven early-type galaxies (NGC 1380, 2434, 3115, 3379, 3585, 5846, and 7192) with different morphological types (E–S0) located in field and group/cluster environ- ments. High-quality spectra were taken with the FORS2 instrument at ESO’s Very Large Telescope. 50% of our data allows an age resolution ∆t/t 0.3 and a metallicity resolution 0.25 0.4 dex, depending on the absolute metallicity.∼ Globular cluster candidates are selected≈ from deep B, V, R, I, K FORS2/ISAAC∼ − photometry with 80 100% success rate inside one effective ra- − dius.
    [Show full text]
  • The Globular Cluster - Galaxy Connection
    The Globular Cluster - Galaxy Connection Ray Sharples (Durham University) Outline of Talk Globular Clusters as Probes of the Formation Histories of Galaxies Open Questions in the Globular Cluster - Galaxy Connection What Can be Done with an 8m (+HST) ? What Could be Done with an E-ELT ? Collaborators: Mark Norris (UNC), Steve Zepf (MSU), Terry Bridges (Queens), Harald Kuntschner (ESO), David Hanes (Queens), Duncan Forbes (Swinburne), Juan-Carlos Forte (La Plata), Markus Kissler-Patig (ESO), Karl Gebhardt (Texas) to name but a few … 2 Why Globular Clusters ? • Found ubiquitously around all galaxies understanding of both spheroidal and disk galaxies • Oldest stellar populations with reliable ages probe earliest phases of galaxy assembly • Scale approximately with host galaxy mass intimate connection with galaxy formation • Simple (?) stellar populations easier age/metallicity determination 3 Key Questions • How do we form GCs (ELT/ALMA) ? • What parameters drive the luminosity (colour) & metallicity distributions of GCSs (8m/ELT) ? • Are the ages & abundances of GCs in ellipticals similar to those in spirals (8m/ELT) ? • What regulates the relative formation of stars vs clusters (ELT) ? • What are the major sites of GC formation (primordial halos, protogalaxies, mergers) (8m/ELT/JWST) ? 4 Star Clusters & Mergers NGC4038/39 4’ KMOS @ VLT March 2011 0”.2 sampling EAGLE @ ELT March 2018 0”.075 sampling Gilbert et al (2001) 5 Bimodality and Mass-Metallicity Relations Milky Way (~150 GCs) BCGs: Z ~ M1/2 for M>106 Mo (Harris 2009) NGC4649
    [Show full text]