Structure and Kinematics of Edge-On Galaxy Discs – V. the Dynamics of Stellar Discs M
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The Professor Comet's Report Early Spring – April 2012
The Professor Comet’s Report 1 Mr. Justin J McCollum (BS, MS Physics) Lab Physics Coordinator Dept. of Physics Lamar University Welcome to the comet report which is a monthly article on the observations of comets by the amateur astronomy community and comet hunters from around the world! This C/2009 P1 Garradd with article is dedicated to the latest reports of available comets for Barred Spiral Galaxy NGC 4236 observations, current state of those comets, future 14 March 2011! predictions, & projections for observations in comet astronomy! Early Spring – April 2012 The Professor Comet’s Report 2 The Current Status of the Predominant Comets for Apr 2012! Comets Designation Orbital Magnitude Trend Observation Constellations Visibility (IAU – MPC) Status Visual (Range in (Night Sky Location) Period Lat.) Garradd 2009 P1 C 7.0* - 7.5 Fading 90°N – 30°S SW region of Ursa Major moving All Night SSW towards the SE region of Lynx. Giacobini - 21P P 9 – 10 Fading Poor N/A Zinner Elongation Lost in the daytime Glare! LINEAR 2011 F1 C 11 .7* Brightening 90°N – 20°S Undergoing retrograde motion All Night between Boötes and Draco thru the late Spring. Gehrels 2 78P P 12.2* Fading 60˚N - 20˚S Moving eastwards across Taurus Early Evening and progressing along the N edge of the Hyades Star Cluster! McNaught 2011 Q2 C 12.5 Fading 70˚N – Eqn. Currently in the S central region Early Morning of Andromeda moving NE between the boundary between Andromeda & Pisces. NEAT 246P/2010 V2 P 12.3* - 13 Possible 65˚N - 60˚S Undergoing retrograde motion All Night Steadiness in the E half of the N central region of Virgo until late June. -
Dwarf Galaxy Dark Matter Density Profiles Inferred from Stellar and Gas Kinematics
ACCEPTED BY APJ Preprint typeset using LATEX style emulateapj v. 5/2/11 DWARF GALAXY DARK MATTER DENSITY PROFILES INFERRED FROM STELLAR AND GAS KINEMATICS* JOSHUA J. ADAMS1,2 , JOSHUA D. SIMON1, MAXIMILIAN H. FABRICIUS3,REMCO C. E. VAN DEN BOSCH4 , JOHN C. BARENTINE5, RALF BENDER3,6,KARL GEBHARDT5,7,GARY J. HILL 5,7,8 , JEREMY D. MURPHY9 ,R.A.SWATERS10, JENS THOMAS3,GLENN VAN DE VEN4, Accepted by ApJ ABSTRACT We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. The gas kinematics of low mass galaxies frequently suggest that they contain constant density DM cores, while N-body simulations instead predict a cuspy profile. We present a data set of high resolution integral field spectroscopy on seven galaxies and measure the stellar and gas kinematics simultaneously. Using Jeans modeling on our full sample, we examine whether gas kinematics in general produce shallower density profiles than are derived from the stars. Although 2/7 galaxies show some localized differences in their rotation curves between the two tracers, estimates of the central logarithmic slope of the DM density profile, γ, are generally robust. The mean and standard deviation of the logarithmic slope for the population are γ = 0.67 0.10 when measured in the stars and γ = 0.58 0.24 when measured in the gas. We also find that the halos± are not under-concentrated at the radii of half± their maximum velocities. Finally, we search for correlations of the DM density profile with stellar velocity anisotropy and other baryonic properties. -
Dark Energy and Extending the Geodesic Equations of Motion: Connecting the Galactic and Cosmological Length Scales
General Relativity and Gravitation (2011) DOI 10.1007/s10714-010-1043-z RESEARCHARTICLE A. D. Speliotopoulos Dark energy and extending the geodesic equations of motion: connecting the galactic and cosmological length scales Received: 23 May 2010 / Accepted: 16 June 2010 c The Author(s) 2010 Abstract Recently, an extension of the geodesic equations of motion using the Dark Energy length scale was proposed. Here, we apply this extension to analyz- ing the motion of test particles at the galactic scale and longer. A cosmological check of the extension is made using the observed rotational velocity curves and core sizes of 1,393 spiral galaxies. We derive the density profile of a model galaxy using this extension, and with it, we calculate σ8 to be 0.73±0.12; this is within +0.049 experimental error of the WMAP value of 0.761−0.048. We then calculate R200 to be 206±53 kpc, which is in reasonable agreement with observations. Keywords Dark energy, Galactic density profile, Density fluctuations, Extensions of the geodesic equations of motion, Galactic rotation curves 1 Introduction In a previous paper [1], we constructed an extension of the geodesic equations of motion (GEOM). This construction is possible because with the discovery of +0.82 −30 3 Dark Energy, ΛDE = (7.21−0.84) × 10 g/cm [2; 3; 4], there is now a length 1/2 scale, λDE = c/(ΛDEG) , associated with the universe. As this length scale is also not associated with the mass of any known particle, this extension does not violate various statements of the equivalence principle. -
Making a Sky Atlas
Appendix A Making a Sky Atlas Although a number of very advanced sky atlases are now available in print, none is likely to be ideal for any given task. Published atlases will probably have too few or too many guide stars, too few or too many deep-sky objects plotted in them, wrong- size charts, etc. I found that with MegaStar I could design and make, specifically for my survey, a “just right” personalized atlas. My atlas consists of 108 charts, each about twenty square degrees in size, with guide stars down to magnitude 8.9. I used only the northernmost 78 charts, since I observed the sky only down to –35°. On the charts I plotted only the objects I wanted to observe. In addition I made enlargements of small, overcrowded areas (“quad charts”) as well as separate large-scale charts for the Virgo Galaxy Cluster, the latter with guide stars down to magnitude 11.4. I put the charts in plastic sheet protectors in a three-ring binder, taking them out and plac- ing them on my telescope mount’s clipboard as needed. To find an object I would use the 35 mm finder (except in the Virgo Cluster, where I used the 60 mm as the finder) to point the ensemble of telescopes at the indicated spot among the guide stars. If the object was not seen in the 35 mm, as it usually was not, I would then look in the larger telescopes. If the object was not immediately visible even in the primary telescope – a not uncommon occur- rence due to inexact initial pointing – I would then scan around for it. -
Dark Energy and Extending the Geodesic Equations of Motion: Connecting the Galactic and Cosmological Length Scales
Gen Relativ Gravit (2010) 42:2913–2938 DOI 10.1007/s10714-010-1043-z RESEARCH ARTICLE Dark energy and extending the geodesic equations of motion: connecting the galactic and cosmological length scales A. D. Speliotopoulos Received: 23 May 2010 / Accepted: 16 June 2010 / Published online: 4 July 2010 © The Author(s) 2010. This article is published with open access at Springerlink.com Abstract Recently, an extension of the geodesic equations of motion using the Dark Energy length scale was proposed. Here, we apply this extension to analyzing the motion of test particles at the galactic scale and longer. A cosmological check of the extension is made using the observed rotational velocity curves and core sizes of 1,393 spiral galaxies. We derive the density profile of a model galaxy using this extension, and with it, we calculate σ8 to be 0.73±0.12; this is within experimental . +0.049 error of the WMAP value of 0 761−0.048. We then calculate R200 to be 206±53 kpc, which is in reasonable agreement with observations. Keywords Dark energy · Galactic density profile · Density fluctuations · Extensions of the geodesic equations of motion · Galactic rotation curves 1 Introduction In a previous paper [1], we constructed an extension of the geodesic equations of motion (GEOM). This construction is possible because with the discovery of Dark = ( . +0.82) × −30 3 λ = Energy, DE 7 21−0.84 10 g/cm [2–4], there is now a length scale, DE 1/2 c/(DEG) , associated with the universe. As this length scale is also not associated with the mass of any known particle, this extension does not violate various statements of the equivalence principle. -
Photometric Properties of Kiso Ultraviolet-Excess Galaxies in the Lynx-Ursa Major Region0
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Photometric Properties of Kiso Ultraviolet-Excess Galaxies in the Lynx-Ursa Major Region0 Tsutomu T. Takeuchi1, 2, Akihiko Tomita3, Kouichiro Nakanishi1, Takako T. Ishii1, 4, Ikuru Iwata5, and Mamoru Sait¯o1 1 Department of Astronomy, Faculty of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, JAPAN 2 Research Fellow of the Japan Society for the Promotion of Science 3 Department of Earth and Astronomical Sciences, Faculty of Education, Wakayama University, Wakayama 640-8510, JAPAN 4 Kwasan and Hida Observatories, Kyoto University, Yamashina-ku, Kyoto 607-8471, JAPAN 5 Toyama Astronomical Observatory, Toyama Science Museum, 49-4 San-no-kuma, Toyama City, Toyama 930-0155, JAPAN Electronic mail: [email protected] Received ; accepted 0Based on observations made at Kiso Observatory, which is operated by Institute of Astronomy, Faculty of Science, University of Tokyo, Japan. –2– ABSTRACT We have performed a systematic study of several regions in the sky where the number of galaxies exhibiting star formation (SF) activity is greater than average. We used Kiso ultraviolet-excess galaxies (KUGs) as our SF-enhanced sample. By statistically comparing the KUG and non-KUG distributions, we discovered four KUG-rich regions with a size of ∼ 10◦ ×10◦. One of these regions corresponds spatially to a filament of length ∼ 60 h−1 Mpc in the Lynx-Ursa Major region (α ∼ 9h − 10h ,δ∼42◦ − 48◦). We call this “the Lynx-Ursa Major (LUM) filament”. We obtained V (RI)C surface photometry of 11 of the KUGs in the LUM filament and used these to investigate the integrated colors, distribution of SF regions, morphologies, and local environments. -
New Evidence for Dark Matter
New evidence for dark matter A. Boyarsky1,2, O. Ruchayskiy1, D. Iakubovskyi2, A.V. Macci`o3, D. Malyshev4 1Ecole Polytechnique F´ed´erale de Lausanne, FSB/ITP/LPPC, BSP CH-1015, Lausanne, Switzerland 2Bogolyubov Institute for Theoretical Physics, Metrologichna str., 14-b, Kiev 03680, Ukraine 3Max-Planck-Institut f¨ur Astronomie, K¨onigstuhl 17, 69117 Heidelberg, Germany 4Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland Observations of star motion, emissions from hot ionized gas, gravitational lensing and other tracers demonstrate that the dynamics of galaxies and galaxy clusters cannot be explained by the Newtonian potential produced by visible matter only [1–4]. The simplest resolution assumes that a significant fraction of matter in the Universe, dominating the dynamics of objects from dwarf galaxies to galaxy clusters, does not interact with electromagnetic radiation (hence the name dark matter). This elegant hypothesis poses, however, a major challenge to the highly successful Standard Model of particle physics, as it was realized that dark matter cannot be made of known elementary particles [4]. The quest for direct evidence of the presence of dark matter and for its properties thus becomes of crucial importance for building a fundamental theory of nature. Here we present a new universal relation, satisfied by matter distributions at all observed scales, and show its amaz- ingly good and detailed agreement with the predictions of the most up-to-date pure dark matter simulations of structure formation in the Universe [5–7]. This behaviour seems to be insensitive to the complicated feedback of ordinary matter on dark matter. -
An Explanation for the Unexpected Diversity of Dwarf Galaxy Rotation Curves
AN EXPLANATION FOR THE UNEXPECTED DIVERSITY OF DWARF GALAXY ROTATION CURVES by Kyle Oman B.Sc., University of Waterloo, 2011 M.Sc., University of Waterloo, 2013 A dissertation submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in the Department of Physics and Astronomy c Kyle Oman, 2017 University of Victoria All rights reserved. This dissertation may not be reproduced in whole or in part, by photocopying or other means, without the permission of the author. ii AN EXPLANATION FOR THE UNEXPECTED DIVERSITY OF DWARF GALAXY ROTATION CURVES by Kyle Oman B.Sc., University of Waterloo, 2011 M.Sc., University of Waterloo, 2013 Supervisory Committee Dr. J. F. Navarro, Supervisor (Department of Physics and Astronomy) Dr. F. Herwig, Departmental Member (Department of Physics and Astronomy) Dr. F. Diacu, Outside Member (Department of Mathematics and Statistics) iii ABSTRACT The cosmological constant + cold dark matter (ΛCDM) theory is the `standard model' of cosmology. Encoded in it are extremely accurate descriptions of the large scale structure of the Universe, despite a very limited number of degrees of freedom. The model struggles, however, to explain some measurements on galactic and smaller scales. The shape of the dark matter distribution toward the centres of galaxies is predicted to be steeply increasing in density (`cuspy') by the theory, yet observations of the rotation curves of some galaxies suggest that it instead reaches a central density plateau (a `core'). This discrepancy is termed the `cusp-core problem'. I propose a new way of quantifying this problem as a diversity in the central mass content of galaxies. -
Arxiv:1207.4189V1 [Astro-Ph.CO] 17 Jul 2012 N a Osdrtrefnaetlpyia Parame- Physical Fundamental Mass Three Alternatively, Ters: Consider Color
The Astrophysical Journal Supplement Series, in press, 17 July 2012 A Preprint typeset using LTEX style emulateapj v. 5/2/11 ANGULAR MOMENTUM AND GALAXY FORMATION REVISITED Aaron J. Romanowsky1, S. Michael Fall2 1University of California Observatories, Santa Cruz, CA 95064, USA 2Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA The Astrophysical Journal Supplement Series, in press, 17 July 2012 ABSTRACT Motivated by a new wave of kinematical tracers in the outer regions of early-type galaxies (ellipticals and lenticulars), we re-examine the role of angular momentum in galaxies of all types. We present new methods for quantifying the specific angular momentum j, focusing mainly on the more challenging case of early-type galaxies, in order to derive firm empirical relations between stellar j⋆ and mass M⋆ (thus extending the work by Fall 1983). We carry out detailed analyses of eight galaxies with kinematical data extending as far out as ten effective radii, and find that data at two effective radii are generally sufficient to estimate total j⋆ reliably. Our results contravene suggestions that ellipticals could harbor large reservoirs of hidden j⋆ in their outer regions owing to angular momentum transport in major mergers. We then carry out a comprehensive analysis of extended kinematic data from the literature for a sample of 100 nearby bright galaxies of all types, placing them on a diagram of ∼ j⋆ versus M⋆. The ellipticals and spirals form two parallel j⋆–M⋆ tracks, with log-slopes of 0.6, which for the spirals is closely related to the Tully-Fisher relation, but for the ellipticals derives from∼ a remarkable conspiracy between masses, sizes, and rotation velocities. -
Dwarf Galaxy Dark Matter Density Profiles Inferred from Stellar and Gas Kinematics∗
The Astrophysical Journal, 789:63 (28pp), 2014 July 1 doi:10.1088/0004-637X/789/1/63 C 2014. The American Astronomical Society. All rights reserved. Printed in the U.S.A. DWARF GALAXY DARK MATTER DENSITY PROFILES INFERRED FROM STELLAR AND GAS KINEMATICS∗ Joshua J. Adams1,10, Joshua D. Simon1, Maximilian H. Fabricius2, Remco C. E. van den Bosch3, John C. Barentine4, Ralf Bender2,5, Karl Gebhardt4,6, Gary J. Hill4,6,7, Jeremy D. Murphy8, R. A. Swaters9, Jens Thomas2, and Glenn van de Ven3 1 Observatories of the Carnegie Institution of Science, 813 Santa Barbara Street, Pasadena, CA 91101, USA; [email protected] 2 Max-Planck Institut fur¨ extraterrestrische Physik, Giessenbachstraße, D-85741 Garching bei Munchen,¨ Germany 3 Max-Planck Institut fur¨ Astronomie, Konigstuhl¨ 17, D-69117 Heidelberg, Germany 4 Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205, USA 5 Universitats-Sternwarte,¨ Ludwig-Maximilians-Universitat,¨ Scheinerstrasse 1, D-81679 Munchen,¨ Germany 6 Texas Cosmology Center, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712, USA 7 McDonald Observatory, 2515 Speedway, Stop C1402, Austin, TX 78712-1205, USA 8 Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544, USA 9 National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719, USA Received 2014 February 19; accepted 2014 May 17; published 2014 June 16 ABSTRACT We present new constraints on the density profiles of dark matter (DM) halos in seven nearby dwarf galaxies from measurements of their integrated stellar light and gas kinematics. -
Dark Matter-Baryon Scaling Relations from Einasto Halo Fits To
Astronomy & Astrophysics manuscript no. paper ©ESO 2019 January 30, 2019 Dark matter-baryon scaling relations from Einasto halo fits to SPARC galaxy rotation curves Amir Ghari1, 2, Benoit Famaey1, Chervin Laporte3†, and Hosein Haghi2, 4 1Université de Strasbourg, CNRS, UMR 7550, Observatoire astronomique de Strasbourg, Strasbourg, France 2Department of Physics, Institute for Advanced Studies in Basic Sciences, 11365-9161, Zanjan, Iran 3Departement of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 1A1, Canada 4Helmholtz-Institut für Strahlen- und Kernphysik (HISKP), Universität Bonn, Bonn, Germany Received xxx; accepted yyy ABSTRACT Dark matter-baryon scaling relations in galaxies are important in order to constrain galaxy formation models. Here, we provide a modern quantitative assessment of those relations, by modelling the rotation curves of galaxies from the Spitzer Photometry and Accurate Rotation Curves (SPARC) database with the Einasto dark halo model. We focus in particular on the comparison between the original SPARC parameters, with constant mass-to-light ratios for bulges and disks, and the parameters for which galaxies follow the tightest radial acceleration relation. We show that fits are improved in the second case, and that the pure halo scaling relations also become tighter. We report that the density at the radius where the slope is −2 is strongly anticorrelated to this radius, and to the Einasto index. The latter is close to unity for a large number of galaxies, indicative of large cores. In terms of dark matter-baryon scalings, we focus on relations between the core properties and the extent of the baryonic component, which are relevant to the cusp-core transformation process. -
A Classical Morphological Analysis of Galaxies in the Spitzer Survey Of
Accepted for publication in the Astrophysical Journal Supplement Series A Preprint typeset using LTEX style emulateapj v. 03/07/07 A CLASSICAL MORPHOLOGICAL ANALYSIS OF GALAXIES IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S4G) Ronald J. Buta1, Kartik Sheth2, E. Athanassoula3, A. Bosma3, Johan H. Knapen4,5, Eija Laurikainen6,7, Heikki Salo6, Debra Elmegreen8, Luis C. Ho9,10,11, Dennis Zaritsky12, Helene Courtois13,14, Joannah L. Hinz12, Juan-Carlos Munoz-Mateos˜ 2,15, Taehyun Kim2,15,16, Michael W. Regan17, Dimitri A. Gadotti15, Armando Gil de Paz18, Jarkko Laine6, Kar´ın Menendez-Delmestre´ 19, Sebastien´ Comeron´ 6,7, Santiago Erroz Ferrer4,5, Mark Seibert20, Trisha Mizusawa2,21, Benne Holwerda22, Barry F. Madore20 Accepted for publication in the Astrophysical Journal Supplement Series ABSTRACT The Spitzer Survey of Stellar Structure in Galaxies (S4G) is the largest available database of deep, homogeneous middle-infrared (mid-IR) images of galaxies of all types. The survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications of S4G galaxies in the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. The CVRHS system follows the precepts of classical de Vaucouleurs (1959) morphology, modified to include recognition of other features such as inner, outer, and nuclear lenses, nuclear rings, bars, and disks, spheroidal galaxies, X patterns and box/peanut structures, OLR subclass outer rings and pseudorings, bar ansae and barlenses, parallel sequence late-types, thick disks, and embedded disks in 3D early-type systems. We show that our CVRHS classifications are internally consistent, and that nearly half of the S4G sample consists of extreme late-type systems (mostly bulgeless, pure disk galaxies) in the range Scd-Im.