Stellar Kinematics in the Galaxy: Reference Frames
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University of Groningen Kinematics and Stellar Populations of Dwarf
University of Groningen Kinematics and stellar populations of dwarf elliptical galaxies Mentz, Jacobus Johannes IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2018 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Mentz, J. J. (2018). Kinematics and stellar populations of dwarf elliptical galaxies. Rijksuniversiteit Groningen. Copyright Other than for strictly personal use, 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), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 09-10-2021 Kinematics and stellar populations of dwarf elliptical galaxies Proefschrift ter verkrijging van het doctoraat aan de Rijksuniversiteit Groningen op gezag van de rector magnificus prof. -
A Radial Velocity Survey of the Carina Nebula's O-Type Stars
A radial velocity survey of the Carina Nebula's O-type stars Item Type Article Authors Kiminki, Megan M; Smith, Nathan Citation Megan M Kiminki, Nathan Smith; A radial velocity survey of the Carina Nebula's O-type stars, Monthly Notices of the Royal Astronomical Society, Volume 477, Issue 2, 21 June 2018, Pages 2068–2086, https://doi.org/10.1093/mnras/sty748 DOI 10.1093/mnras/sty748 Publisher OXFORD UNIV PRESS Journal MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Rights © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. Download date 30/09/2021 21:29:15 Item License http://rightsstatements.org/vocab/InC/1.0/ Version Final published version Link to Item http://hdl.handle.net/10150/628380 MNRAS 477, 2068–2086 (2018) doi:10.1093/mnras/sty748 Advance Access publication 2018 March 21 A radial velocity survey of the Carina Nebula’s O-type stars Megan M. Kiminki‹ and Nathan Smith Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721, USA Accepted 2018 March 14. Received 2018 March 11; in original form 2017 June 17 ABSTRACT We have obtained multi-epoch observations of 31 O-type stars in the Carina Nebula using the CHIRON spectrograph on the CTIO/SMARTS 1.5-m telescope. We measure their radial velocities to 1–2 km s−1 precision and present new or updated orbital solutions for the binary systems HD 92607, HD 93576, HDE 303312, and HDE 305536. We also compile radial velocities from the literature for 32 additional O-type and evolved massive stars in the region. -
Relaxation Time
Today in Astronomy 142: the Milky Way’s disk More on stars as a gas: stellar relaxation time, equilibrium Differential rotation of the stars in the disk The local standard of rest Rotation curves and the distribution of mass The rotation curve of the Galaxy Figure: spiral structure in the first Galactic quadrant, deduced from CO observations. (Clemens, Sanders, Scoville 1988) 21 March 2013 Astronomy 142, Spring 2013 1 Stellar encounters: relaxation time of a stellar cluster In order to behave like a gas, as we assumed last time, stars have to collide elastically enough times for their random kinetic energy to be shared in a thermal fashion. But stellar encounters, even distant ones, are rare on human time scales. How long does it take a cluster of stars to thermalize? One characteristic time: the time between stellar elastic encounters, called the relaxation time. If a gravitationally bound cluster is a lot older than its relaxation time, then the stars will be describable as a gas (the star system has temperature, pressure, etc.). 21 March 2013 Astronomy 142, Spring 2013 2 Stellar encounters: relaxation time of a stellar cluster (continued) Suppose a star has a gravitational “sphere of influence” with radius r (>>R, the radius of the star), and moves at speed v between encounters, with its sphere of influence sweeping out a cylinder as it does: v V= π r2 vt r vt If the number density of stars (stars per unit volume) is n, then there will be exactly one star in the cylinder if 2 1 nV= nπ r vtcc =⇒=1 t Relaxation time nrvπ 2 21 March 2013 Astronomy 142, Spring 2013 3 Stellar encounters: relaxation time of a stellar cluster (continued) What is the appropriate radius, r? Choose that for which the gravitational potential energy is equal in magnitude to the average stellar kinetic energy. -
In-Class Worksheet on the Galaxy
Ay 20 / Fall Term 2014-2015 Hillenbrand In-Class Worksheet on The Galaxy Today is another collaborative learning day. As earlier in the term when working on blackbody radiation, divide yourselves into groups of 2-3 people. Then find a broad space at the white boards around the room. Work through the logic of the following two topics. Oort Constants. From the vantage point of the Sun within the plane of the Galaxy, we have managed to infer its structure by observing line-of-sight velocities as a function of galactic longitude. Let’s see why this works by considering basic geometry and observables. • Begin by drawing a picture. Consider the Sun at a distance Ro from the center of the Galaxy (a.k.a. the GC) on a circular orbit with velocity θ(Ro) = θo. Draw several concentric circles interior to the Sun’s orbit that represent the circular orbits of other stars or gas. Now consider some line of sight at a longitude l from the direction of the GC, that intersects one of your concentric circles at only one point. The circular velocity of an object on that (also circular) orbit at galactocentric distance R is θ(R); the direction of θ(R) forms an angle α with respect to the line of sight. You should also label the components of θ(R): they are vr along the line-of-sight, and vt tangential to the line-of-sight. If you need some assistance, Figure 18.14 of C/O shows the desired result. What we are aiming to do is derive formulae for vr and vt, which in principle are measureable, as a function of the distance d from us, the galactic longitude l, and some constants. -
Stellar Dynamics and Stellar Phenomena Near a Massive Black Hole
Stellar Dynamics and Stellar Phenomena Near A Massive Black Hole Tal Alexander Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl St, Rehovot, Israel 76100; email: [email protected] | Author's original version. To appear in Annual Review of Astronomy and Astrophysics. See final published version in ARA&A website: www.annualreviews.org/doi/10.1146/annurev-astro-091916-055306 Annu. Rev. Astron. Astrophys. 2017. Keywords 55:1{41 massive black holes, stellar kinematics, stellar dynamics, Galactic This article's doi: Center 10.1146/((please add article doi)) Copyright c 2017 by Annual Reviews. Abstract All rights reserved Most galactic nuclei harbor a massive black hole (MBH), whose birth and evolution are closely linked to those of its host galaxy. The unique conditions near the MBH: high velocity and density in the steep po- tential of a massive singular relativistic object, lead to unusual modes of stellar birth, evolution, dynamics and death. A complex network of dynamical mechanisms, operating on multiple timescales, deflect stars arXiv:1701.04762v1 [astro-ph.GA] 17 Jan 2017 to orbits that intercept the MBH. Such close encounters lead to ener- getic interactions with observable signatures and consequences for the evolution of the MBH and its stellar environment. Galactic nuclei are astrophysical laboratories that test and challenge our understanding of MBH formation, strong gravity, stellar dynamics, and stellar physics. I review from a theoretical perspective the wide range of stellar phe- nomena that occur near MBHs, focusing on the role of stellar dynamics near an isolated MBH in a relaxed stellar cusp. -
Probabilistic Fundamental Stellar Parameters
Solving some r-process issues in chemical evolution Ralph Schönrich (Oxford) Paul McMillan, Laurent Eyer, Walter Dehnen James Binney, Michael Aumer, Luca Casagrande Martin Asplund, David Weinberg Hokotezaka et al. (2018) Chemical evolution gas inflow/onflow IGM stars Chemical evolution gas Fe-rich inflow/onflow SNIa SNII+Ib,c IGM a-rich progenitors stars Chemical evolution gas Fe-rich inflow/onflow SNIa SNII+Ib,c IGM a-rich r-process progenitors outflow NM stars Hokotezaka et al. (2018) Some simple thoughts Assume constant loss fraction from yields What about the thick disc ridge? Neutron star mergers → r process later Doing a simple model Doing a simple model Chemical evolution gas Fe-rich inflow/onflow SNIa SNII+Ib,c IGM a-rich r-process progenitors outflow NM stars Trying to escape the usual links Hot air does not only make you fly, it can delay your evolution Short-lived isotopes in the early solar system Wasserburg et al. (2006) Chemical evolution gas condensation warm cool evaporation Fe-rich inflow/onflow direct enrichment SNIa SNII+Ib,c IGM a-rich r-process progenitors outflow NM stars Introducing the hot gas phase Introducing the hot gas phase Some simple thoughts Assume constant loss fraction from yields What about the thick disc ridge? Neutron star mergers → r process later Some simple thoughts Assume constant loss fraction from yields What about the thick disc ridge? Neutron star mergers → r process later Using the different factor Using the different factor Summary The hot vs. cold ISM is central for the evolution of „early“ -
Two Stellar Components in the Halo of the Milky Way
1 Two stellar components in the halo of the Milky Way Daniela Carollo1,2,3,5, Timothy C. Beers2,3, Young Sun Lee2,3, Masashi Chiba4, John E. Norris5 , Ronald Wilhelm6, Thirupathi Sivarani2,3, Brian Marsteller2,3, Jeffrey A. Munn7, Coryn A. L. Bailer-Jones8, Paola Re Fiorentin8,9, & Donald G. York10,11 1INAF - Osservatorio Astronomico di Torino, 10025 Pino Torinese, Italy, 2Department of Physics & Astronomy, Center for the Study of Cosmic Evolution, 3Joint Institute for Nuclear Astrophysics, Michigan State University, E. Lansing, MI 48824, USA, 4Astronomical Institute, Tohoku University, Sendai 980-8578, Japan, 5Research School of Astronomy & Astrophysics, The Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Australian Capital Territory 2611, Australia, 6Department of Physics, Texas Tech University, Lubbock, TX 79409, USA, 7US Naval Observatory, P.O. Box 1149, Flagstaff, AZ 86002, USA, 8Max-Planck-Institute für Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany, 9Department of Physics, University of Ljubljana, Jadronska 19, 1000, Ljubljana, Slovenia, 10Department of Astronomy and Astrophysics, Center, 11The Enrico Fermi Institute, University of Chicago, Chicago, IL, 60637, USA The halo of the Milky Way provides unique elemental abundance and kinematic information on the first objects to form in the Universe, which can be used to tightly constrain models of galaxy formation and evolution. Although the halo was once considered a single component, evidence for is dichotomy has slowly emerged in recent years from inspection of small samples of halo objects. Here we show that the halo is indeed clearly divisible into two broadly overlapping structural components -- an inner and an outer halo – that exhibit different spatial density profiles, stellar orbits and stellar metallicities (abundances of elements heavier than helium). -
Book of Abstracts
KIAA / DoA 2019 Postdoc Science Days Book of Abstracts December 10th and 11th 2019 in the KIAA Auditorium Schedule Time Speaker Title Page k Tuesday December 10th 2019: 9:30 - 9:35 Gregory Herczeg Introduction Galaxy Formation and Evolution 9:35 - 9:55 Tomonari Michiyama (道山知成) Sub-mm observations of nearby merging galaxies 3 9:55 - 10:15 Bumhyun Lee (이범현) Deep Impact: molecular gas properties under strong ram pressure 3 10:15 - 10:35 Kexin Guo (郭可欣) The Roles of AGNs and Dynamical Process in Star Formation Quenching in Nearby 4 Disk Galaxies 10:35 - 10:55 Sonali Sachdeva Correlation of structure and stellar properties of galaxies 4 10:55 - 11:15 Min Du (杜敏) Intrinsic structures of disk galaxies identified in kinematics 5 Tea & Coffee Break Pulsars and Radio Sources 11:35 - 11:55 Xuhao Wu (武旭浩) How Can The Pulsar’s Maximum Mass Reach ∼3 M⊙ 5 11:55 - 12:15 Nicolas Caballero Pulsar-based timescales 5 12:15 - 12:35 Wei Hua Wang (汪卫华) The unique post-glitch behavior of the Crab pulsar as a possible signature of 6 superfluid PBF Lunch ISM, Star-Formation, and Supernovae 13:40 - 14:00 Toky Randriamampandry CALIFA bar pattern speed: toward a bar scaling relation 6 14:00 - 14:20 Moran Xia (夏默然) The Origin of The Stellar Mass-Stellar Metallicity Relation In the Milky Way 7 Satellites and Beyond 14:20 - 14:40 Juan Molina A spatially-resolved view of the gas kinematics in two star-forming galaxies at z~1.47 7 seen with ALMA and VLT-SINFONI 14:40 - 15:00 John Graham The Metallicity Distribution of Type II SNe Hosts 8 Tea & Coffee Break Active Galactic -
Near-Field Cosmology with Extremely Metal-Poor Stars
AA53CH16-Frebel ARI 29 July 2015 12:54 Near-Field Cosmology with Extremely Metal-Poor Stars Anna Frebel1 and John E. Norris2 1Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; email: [email protected] 2Research School of Astronomy & Astrophysics, The Australian National University, Mount Stromlo Observatory, Weston, Australian Capital Territory 2611, Australia; email: [email protected] Annu. Rev. Astron. Astrophys. 2015. 53:631–88 Keywords The Annual Review of Astronomy and Astrophysics is stellar abundances, stellar evolution, stellar populations, Population II, online at astro.annualreviews.org Galactic halo, metal-poor stars, carbon-enhanced metal-poor stars, dwarf This article’s doi: galaxies, Population III, first stars, galaxy formation, early Universe, 10.1146/annurev-astro-082214-122423 cosmology Copyright c 2015 by Annual Reviews. All rights reserved Abstract The oldest, most metal-poor stars in the Galactic halo and satellite dwarf galaxies present an opportunity to explore the chemical and physical condi- tions of the earliest star-forming environments in the Universe. We review Access provided by California Institute of Technology on 01/11/17. For personal use only. the fields of stellar archaeology and dwarf galaxy archaeology by examin- Annu. Rev. Astron. Astrophys. 2015.53:631-688. Downloaded from www.annualreviews.org ing the chemical abundance measurements of various elements in extremely metal-poor stars. Focus on the carbon-rich and carbon-normal halo star populations illustrates how these provide insight into the Population III star progenitors responsible for the first metal enrichment events. We extend the discussion to near-field cosmology, which is concerned with the forma- tion of the first stars and galaxies, and how metal-poor stars can be used to constrain these processes. -
Lecture 10 Milky Way II
Measuring Structure of the Galaxy • To invert the measured distribution of stars One needs to make a lot – A(m,l,b): # of stars at an of 'corrections' the biggest one apparent mag m, at galactic is due to extinction so one coordinates l,b per sq degree does not repeat Herschel's error! per unit mag. – N(m,l,b): cumulative # of stars with mag < m, at galactic coordinates l,b per sq degree per unit mag. N(m,l,b)=∫ A(m',l,b) dm Into a true 3-D structure 36 Need to Measure Extinction Accurately 37 APOGEE Results • Metallicity across the Milky Way • An example of the fine grain knowledge now being obtained. 38 Gaia Capability • Gaia will survey ~1/4 of the MW (Luri and Robin) 39 Early GAIA Results • Proper motions in the M67 star cluster-accuracies of ~5mas/year (5x10-9 radians/year or 4.3x10-5 pc/year (42 km/sec- 2.5x the speed of the earth around the sun) at distance of M67 ) 40 MW II • Use of gas (HI) to trace velocity field and thus mass of the disk (discuss a bit of the geometry details in the next lecture) – dependence on distance to center of MW • properties of MW (e.g. mass of components) • Cosmic Rays – only directly observable in MW • Start of dynamics 41 Timescales 7 • crossing time tc=2R/σ∼5x10 yrs (R10kpc/v200) • dynamical time td=sqrt(3π/16Gρ)- related to the orbital time; assumption homogenous sphere of density ρ • Relaxation time- the time for a system to 'forget' its initial conditions S+G (eq. -
Dwarf Galaxies 1 Planck “Merger Tree” Hierarchical Structure Formation
04.04.2019 Grebel: Dwarf Galaxies 1 Planck “Merger Tree” Hierarchical Structure Formation q Larger structures form q through successive Illustris q mergers of smaller simulation q structures. q If baryons are Time q involved: Observable q signatures of past merger q events may be retained. ➙ Dwarf galaxies as building blocks of massive galaxies. Potentially traceable; esp. in galactic halos. Fundamental scenario: q Surviving dwarfs: Fossils of galaxy formation q and evolution. Large structures form through numerous mergers of smaller ones. 04.04.2019 Grebel: Dwarf Galaxies 2 Satellite Disruption and Accretion Satellite disruption: q may lead to tidal q stripping (up to 90% q of the satellite’s original q stellar mass may be lost, q but remnant may survive), or q to complete disruption and q ultimately satellite accretion. Harding q More massive satellites experience Stellar tidal streams r r q higher dynamical friction dV M ρ V from different dwarf ∝ − r 3 galaxy accretion q and sink more rapidly. dt V events lead to ➙ Due to the mass-metallicity relation, expect a highly sub- q more metal-rich stars to end up at smaller radii. structured halo. 04.04.2019 € Grebel: Dwarf Galaxies Johnston 3 De Lucia & Helmi 2008; Cooper et al. 2010 accreted stars (ex situ) in-situ stars Stellar Halo Origins q Stellar halos composed in part of q accreted stars and in part of stars q formed in situ. Rodriguez- q Halos grow from “from inside out”. Gomez et al. 2016 q Wide variety of satellite accretion histories from smooth growth to discrete events. -
High-Drag Interstellar Objects and Galactic Dynamical Streams
Draft version March 25, 2019 Typeset using LATEX twocolumn style in AASTeX62 High-Drag Interstellar Objects And Galactic Dynamical Streams T.M. Eubanks1 1Space Initiatives Inc, Clifton, Virginia 20124 (Received; Revised March 25, 2019; Accepted) Submitted to ApJL ABSTRACT The nature of 1I/’Oumuamua (henceforth, 1I), the first interstellar object known to pass through the solar system, remains mysterious. Feng & Jones noted that the incoming 1I velocity vector “at infinity” (v∞) is close to the motion of the Pleiades dynamical stream (or Local Association), and suggested that 1I is a young object ejected from a star in that stream. Micheli et al. subsequently detected non-gravitational acceleration in the 1I trajectory; this acceleration would not be unusual in an active comet, but 1I observations failed to reveal any signs of activity. Bialy & Loeb hypothesized that the anomalous 1I acceleration was instead due to radiation pressure, which would require an extremely low mass-to-area ratio (or area density). Here I show that a low area density can also explain the very close kinematic association of 1I and the Pleiades stream, as it renders 1I subject to drag capture by interstellar gas clouds. This supports the radiation pressure hypothesis and suggests that there is a significant population of low area density ISOs in the Galaxy, leading, through gas drag, to enhanced ISO concentrations in the galactic dynamical streams. Any interstellar object entrained in a dynamical stream will have a predictable incoming v∞; targeted deep surveys using this information should be able to find dynamical stream objects months to as much as a year before their perihelion, providing the lead time needed for fast-response missions for the future in situ exploration of such objects.