Gaia DR2 Proper Motions of Dwarf Galaxies Within 420 Kpc Orbits, Milky Way Mass, Tidal Influences, Planar Alignments, and Group Infall
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Arxiv:1303.1406V1 [Astro-Ph.HE] 6 Mar 2013 the flux of Gamma-Rays from Dark Matter Annihilation Takes a Surprisingly Simple Form 2
4th Fermi Symposium : Monterey, CA : 28 Oct-2 Nov 2012 1 The VERITAS Dark Matter Program Alex Geringer-Sameth∗ for the VERITAS Collaboration Department of Physics, Brown University, 182 Hope St., Providence, RI 02912 The VERITAS array of Cherenkov telescopes, designed for the detection of gamma-rays in the 100 GeV-10 TeV energy range, performs dark matter searches over a wide variety of targets. VERITAS continues to carry out focused observations of dwarf spheroidal galaxies in the Local Group, of the Milky Way galactic center, and of Fermi-LAT unidentified sources. This report presents our extensive observations of these targets, new statistical techniques, and current constraints on dark matter particle physics derived from these observations. 1. Introduction Earth's atmosphere as a target for high-energy cosmic particles. An incoming gamma-ray may interact in the The characterization of dark matter beyond its Earth's atmosphere, initiating a shower of secondary gravitational interactions is currently a central task particles that travel at speeds greater than the local of modern particle physics. A generic and well- (in air) speed of light. This entails the emission of motivated dark matter candidate is a weakly in- ultraviolet Cherenkov radiation. The four telescopes teracting massive particle (WIMP). Such particles of the VERITAS array capture images of the shower have masses in the GeV-TeV range and may inter- using this Cherenkov light. The images are analyzed act with the Standard Model through the weak force. to reconstruct the direction of the original particle as Searches for WIMPs are performed at particle accel- well as its energy. -
15Th October at 19:00 Hours Or 7Pm AEST
TheSky (c) Astronomy Software 1984-1998 TheSky (c) Astronomy Software 1984-1998 URSA MINOR CEPHEUS CASSIOPEIA DRACO Night sky map OctoberDRACO 2017 URSA MAJOR North North STAR BRIGHTNESS Zero or brighter 1st magnitude nd LACERTA Deneb 2 NE rd NE Vega CYGNUS CANES VENATICI LYRAANDROMEDA 3 Vega NW th NW 4 LYRA LEO MINOR CORONA BOREALIS HERCULES BOOTES CORONA BOREALIS HERCULES VULPECULA COMA BERENICES Arcturus PEGASUS SAGITTA DELPHINUS SAGITTA SERPENS LEO Altair EQUULEUS PISCES Regulus AQUILAVIRGO Altair OPHIUCHUS First Quarter Moon SERPENS on the 28th Spica AQUARIUS LIBRA Zubenelgenubi SCUTUM OPHIUCHUS CORVUS Teapot SEXTANS SERPENS CAPRICORNUS SERPENSCRATER AQUILA SCUTUM East East Antares SAGITTARIUS CETUS PISCIS AUSTRINUS P SATURN Centre of the Galaxy MICROSCOPIUM Centre of the Galaxy HYDRA West SCORPIUS West LUPUS SAGITTARIUS SCULPTOR CORONA AUSTRALIS Antares GRUS CENTAURUS LIBRA SCORPIUS NORMAINDUS TELESCOPIUM CORONA AUSTRALIS ANTLIA Zubenelgenubi ARA CIRCINUS Hadar Alpha Centauri PHOENIX Mimosa CRUX ARA CAPRICORNUS TRIANGULUM AUSTRALEPAVO PYXIS TELESCOPIUM NORMAVELALUPUS FORNAX TUCANA MUSCA 47 Tucanae MICROSCOPIUM Achernar APUS ERIDANUS PAVO SMC TRIANGULUM AUSTRALE CIRCINUS OCTANSCHAMAELEON APUS CARINA HOROLOGIUMINDUS HYDRUS Alpha Centauri OCTANS SouthSouth CelestialCelestial PolePole VOLANS Hadar PUPPIS RETICULUM POINTERS SOUTHERN CROSS PISCIS AUSTRINUS MENSA CHAMAELEONMENSA MUSCA CENTAURUS Adhara CANIS MAJOR CHART KEY LMC Mimosa SE GRUS DORADO SMC CAELUM LMCCRUX Canopus Bright star HYDRUS TUCANA SWSW MOON PHASE Faint star VOLANS DORADO -
A Revised View of the Canis Major Stellar Overdensity with Decam And
MNRAS 501, 1690–1700 (2021) doi:10.1093/mnras/staa2655 Advance Access publication 2020 October 14 A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars Downloaded from https://academic.oup.com/mnras/article/501/2/1690/5923573 by Consejo Superior de Investigaciones Cientificas (CSIC) user on 15 March 2021 Julio A. Carballo-Bello ,1‹ David Mart´ınez-Delgado,2 Jesus´ M. Corral-Santana ,3 Emilio J. Alfaro,2 Camila Navarrete,3,4 A. Katherina Vivas 5 and Marcio´ Catelan 4,6 1Instituto de Alta Investigacion,´ Universidad de Tarapaca,´ Casilla 7D, Arica, Chile 2Instituto de Astrof´ısica de Andaluc´ıa, CSIC, E-18080 Granada, Spain 3European Southern Observatory, Alonso de Cordova´ 3107, Casilla 19001, Santiago, Chile 4Millennium Institute of Astrophysics, Santiago, Chile 5Cerro Tololo Inter-American Observatory, NSF’s National Optical-Infrared Astronomy Research Laboratory, Casilla 603, La Serena, Chile 6Instituto de Astrof´ısica, Facultad de F´ısica, Pontificia Universidad Catolica´ de Chile, Av. Vicuna˜ Mackenna 4860, 782-0436 Macul, Santiago, Chile Accepted 2020 August 27. Received 2020 July 16; in original form 2020 February 24 ABSTRACT We present the Dark Energy Camera (DECam) imaging combined with Gaia Data Release 2 (DR2) data to study the Canis Major overdensity. The presence of the so-called Blue Plume stars in a low-pollution area of the colour–magnitude diagram allows us to derive the distance and proper motions of this stellar feature along the line of sight of its hypothetical core. The stellar overdensity extends on a large area of the sky at low Galactic latitudes, below the plane, and in the range 230◦ <<255◦. -
Survey of Britain's Most Powerful Radial Engine : an Example Of
JULY 5TH, 1945 FLIGHT Survey of Britain's Most Powerful Radial Engine : An Example of . r l^OgiCal Layout to Achieve Compactness with Power T has been eommbn knowledge far some time past that •power figure of 3,500, the b.h.p. /litre of both Hercules the Bristol Aeroplane Co., Ltd., have been engaged with Centaurus is 46.5, although we know that the latter engine the production of a larger and improved model in the is somewhat better than this, as may be rough!y indicated age of radial, air-cooled, sleeve-valve engines with which by the figures for b.h.p./sq. in. of piston area, these ey have for so long enhanced their reputation. This being respectively:. Hercules 4.93. and Centaurus better mmon knowledge—the result of unofficial "leaks"— than 5.34. • f ibraced the facts that the new engine was an 18-cylinder : Cooling Arrangements lit of over 2,000 h.p. and was called the Centaurug.. ther than this nothing much was generally known until As an indication of refinement in the design of the cowl- nctioned reference, to the engine was made with the ing, if. we take as a datum the frontal area of the Hercules lease of the Short Shetland flying boat (Flight, May 17th, at 2,122 sq. in. and give it the value of unity, then the 145), when it was revealed that the Centaurus was of Centaurus frontal area of 2,402 sq. in. gives a comparative 'er 2,500 h.p. ratio of 1.13:1, which is well below the relative h.p..ratio Even now we are not permitted to give any indication of 1.385 :1, itself a conservative figure. -
The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia
MNRAS 000,1{20 (2019) Preprint 14 November 2019 Compiled using MNRAS LATEX style file v3.0 The Milky Way's Disk of Classical Satellite Galaxies in Light of Gaia DR2 Marcel S. Pawlowski,1? and Pavel Kroupa2;3 1Leibniz-Institut fur¨ Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany 2Helmholtz-Institut fur¨ Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, D- 53115 Bonn, Germany 3Charles University in Prague, Faculty of Mathematics and Physics, Astronomical Institute, V Holeˇsoviˇck´ach 2, CZ-180 00 Praha 8, Czech Republic Accepted 2019 November 7. Received 2019 November 7; in original form 2019 August 26 ABSTRACT We study the correlation of orbital poles of the 11 classical satellite galaxies of the Milky Way, comparing results from previous proper motions with the independent data by Gaia DR2. Previous results on the degree of correlation and its significance are confirmed by the new data. A majority of the satellites co-orbit along the Vast Polar Structure, the plane (or disk) of satellite galaxies defined by their positions. The orbital planes of eight satellites align to < 20◦ with a common direction, seven even orbit in the same sense. Most also share similar specific angular momenta, though their wide distribution on the sky does not support a recent group infall or satellites- of-satellites origin. The orbital pole concentration has continuously increased as more precise proper motions were measured, as expected if the underlying distribution shows true correlation that is washed out by observational uncertainties. The orbital poles of the up to seven most correlated satellites are in fact almost as concentrated as expected for the best-possible orbital alignment achievable given the satellite posi- tions. -
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Distances to Local Group Galaxies
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server Distances to Local Group Galaxies Alistair R. Walker Cerro Tololo Inter-American Observatory, NOAO, Casilla 603, la Serena, Chile Abstract. Distances to galaxies in the Local Group are reviewed. In particular, the distance to the Large Magellanic Cloud is found to be (m M)0 =18:52 0:10, cor- − ± responding to 50; 600 2; 400 pc. The importance of M31 as an analog of the galaxies observed at greater distances± is stressed, while the variety of star formation and chem- ical enrichment histories displayed by Local Group galaxies allows critical evaluation of the calibrations of the various distance indicators in a variety of environments. 1 Introduction The Local Group (hereafter LG) of galaxies has been comprehensively described in the monograph by Sidney van den Berg [1], with update in [2]. The zero- velocity surface has radius of a little more than 1 Mpc, therefore the small sub-group of galaxies consisting of NGC 3109, Antlia, Sextans A and Sextans B lie outside the the LG by this definition, as do galaxies in the direction of the nearby Sculptor and IC342/Maffei groups. Thus the LG consists of two large spirals (the Galaxy and M31) each with their entourage of 11 and 10 smaller galaxies respectively, the dwarf spiral M33, and 13 other galaxies classified as either irregular or spherical. We have here included NGC 147 and NGC 185 as members of the M31 sub-group [60], whether they are actually bound to M31 is not proven. -
Distribution of Phantom Dark Matter in Dwarf Spheroidals Alistair O
A&A 640, A26 (2020) Astronomy https://doi.org/10.1051/0004-6361/202037634 & c ESO 2020 Astrophysics Distribution of phantom dark matter in dwarf spheroidals Alistair O. Hodson1,2, Antonaldo Diaferio1,2, and Luisa Ostorero1,2 1 Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, 10125 Torino, Italy 2 Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Torino, Via P. Giuria 1, 10125 Torino, Italy e-mail: [email protected],[email protected] Received 31 January 2020 / Accepted 25 May 2020 ABSTRACT We derive the distribution of the phantom dark matter in the eight classical dwarf galaxies surrounding the Milky Way, under the assumption that modified Newtonian dynamics (MOND) is the correct theory of gravity. According to their observed shape, we model the dwarfs as axisymmetric systems, rather than spherical systems, as usually assumed. In addition, as required by the assumption of the MOND framework, we realistically include the external gravitational field of the Milky Way and of the large-scale structure beyond the Local Group. For the dwarfs where the external field dominates over the internal gravitational field, the phantom dark matter has, from the star distribution, an offset of ∼0:1−0:2 kpc, depending on the mass-to-light ratio adopted. This offset is a substantial fraction of the dwarf half-mass radius. For Sculptor and Fornax, where the internal and external gravitational fields are comparable, the phantom dark matter distribution appears disturbed with spikes at the locations where the two fields cancel each other; these features have little connection with the distribution of the stars within the dwarfs. -
Introduction to Astronomy from Darkness to Blazing Glory
Introduction to Astronomy From Darkness to Blazing Glory Published by JAS Educational Publications Copyright Pending 2010 JAS Educational Publications All rights reserved. Including the right of reproduction in whole or in part in any form. Second Edition Author: Jeffrey Wright Scott Photographs and Diagrams: Credit NASA, Jet Propulsion Laboratory, USGS, NOAA, Aames Research Center JAS Educational Publications 2601 Oakdale Road, H2 P.O. Box 197 Modesto California 95355 1-888-586-6252 Website: http://.Introastro.com Printing by Minuteman Press, Berkley, California ISBN 978-0-9827200-0-4 1 Introduction to Astronomy From Darkness to Blazing Glory The moon Titan is in the forefront with the moon Tethys behind it. These are two of many of Saturn’s moons Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA 2 Introduction to Astronomy Contents in Brief Chapter 1: Astronomy Basics: Pages 1 – 6 Workbook Pages 1 - 2 Chapter 2: Time: Pages 7 - 10 Workbook Pages 3 - 4 Chapter 3: Solar System Overview: Pages 11 - 14 Workbook Pages 5 - 8 Chapter 4: Our Sun: Pages 15 - 20 Workbook Pages 9 - 16 Chapter 5: The Terrestrial Planets: Page 21 - 39 Workbook Pages 17 - 36 Mercury: Pages 22 - 23 Venus: Pages 24 - 25 Earth: Pages 25 - 34 Mars: Pages 34 - 39 Chapter 6: Outer, Dwarf and Exoplanets Pages: 41-54 Workbook Pages 37 - 48 Jupiter: Pages 41 - 42 Saturn: Pages 42 - 44 Uranus: Pages 44 - 45 Neptune: Pages 45 - 46 Dwarf Planets, Plutoids and Exoplanets: Pages 47 -54 3 Chapter 7: The Moons: Pages: 55 - 66 Workbook Pages 49 - 56 Chapter 8: Rocks and Ice: -
Instruction Manual
1 Contents 1. Constellation Watch Cosmo Sign.................................................. 4 2. Constellation Display of Entire Sky at 35° North Latitude ........ 5 3. Features ........................................................................................... 6 4. Setting the Time and Constellation Dial....................................... 8 5. Concerning the Constellation Dial Display ................................ 11 6. Abbreviations of Constellations and their Full Spellings.......... 12 7. Nebulae and Star Clusters on the Constellation Dial in Light Green.... 15 8. Diagram of the Constellation Dial............................................... 16 9. Precautions .................................................................................... 18 10. Specifications................................................................................. 24 3 1. Constellation Watch Cosmo Sign 2. Constellation Display of Entire Sky at 35° The Constellation Watch Cosmo Sign is a precisely designed analog quartz watch that North Latitude displays not only the current time but also the correct positions of the constellations as Right ascension scale Ecliptic Celestial equator they move across the celestial sphere. The Cosmo Sign Constellation Watch gives the Date scale -18° horizontal D azimuth and altitude of the major fixed stars, nebulae and star clusters, displays local i c r e o Constellation dial setting c n t s ( sidereal time, stellar spectral type, pole star hour angle, the hours for astronomical i o N t e n o l l r f -
Dark Matter Signals from Draco and Willman 1: Prospects for MAGIC II
Preprint typeset in JHEP style - HYPER VERSION astro-ph/0809.2269 Dark Matter Signals from Draco and Willman 1: Prospects for MAGIC II and CTA Torsten Bringmann Department of Physics, Stockholm University, AlbaNova, University Centre, S-106 91 Stockholm, Sweden E-mail: [email protected] Michele Doro Department of Physics G. Galilei, University of Padova & INFN, via Marzolo 8, 35131 Padova, Italy E-mail: [email protected] Mattia Fornasa Department of Physics G. Galilei, University of Padova & INFN, via Marzolo 8, 35131 Padova, Italy Institut d’Astrophysique de Paris, boulevard Arago 98bis, 75014, Paris, France E-mail: [email protected] Abstract: The next generation of ground-based Imaging Air Cherenkov Telescopes will play an important role in indirect dark matter searches. In this article, we consider two particularly promis- ing candidate sources for dark matter annihilation signals, the nearby dwarf galaxies Draco and Willman 1, and study the prospects of detecting such a signal for the soon-operating MAGIC II telescope system as well as for the planned installation of CTA, taking special care of describing the experimental features that affect the detectional prospects. For the first time in such studies, we fully take into account the effect of internal bremsstrahlung, which has recently been shown to arXiv:0809.2269v3 [astro-ph] 21 Jan 2009 considerably enhance, in some cases, the gamma-ray flux in the high energies domain where At- mospheric Cherenkov Telescopes operate, thus leading to significantly harder annihilation spectra than traditionally considered. While the detection of the spectral features introduced by internal bremsstrahlung would constitute a smoking gun signature for dark matter annihilation, we find that for most models the overall flux still remains at a level that will be challenging to detect, unless one adopts somewhat favorable descriptions of the smooth dark matter distribution in the dwarfs. -
Wyn Evans Institute of Astronomy, Cambridge
DARK MATTER SUBSTRUCTURES IN THE NEARBY UNIVERSE Wyn Evans Institute of Astronomy, Cambridge Monday, 16 July 2012 DARK MATTER 1. The dwarf spheroidals 2. The ultra-faints 3. The clouds & streams 4. The unknown Monday, 16 July 2012 DWARF SPHEROIDALS Image (35’ by 35’) of the Sculptor dwarf spheroidal taken with the NOAO CTIO 4 m telescope. Monday, 16 July 2012 DWARF SPHEROIDALS Surrounding the Milky Way are 9 classical dwarf spheroidal galaxies (Scu, For, Leo I, Leo II, UMi, Dra, Car, Sex, Sgr). These contain intermediate age to old stellar populations and no gas. They have velocity dispersions ∼ 8-10 km/s, half-light radius ∼ 200-300 pc, and absolute magnitudes MV brighter than -8. They are all highly dark matter dominated, and are natural targets for indirect detection experiments. What are their dark matter profiles? Are they cusped or cored? Monday, 16 July 2012 DWARF SPHEROIDALS Radial velocity surveys with multi-object spectrographs have now provided datasets of thousands of velocities for the giants stars. Early hopes that the photometry and line of sight velocity dispersion profile could be used to constrain the dark halo give way to pessimism. Most early modelers used the spherical Jeans equations to deduce dark matter properties at the center. Monday, 16 July 2012 JEANS EQUATIONS • The spherical Jeans equation is dangerous! If the light profile is cored (Plummer), then assuming isotropy gives a cored dark matter density. If the light profile is cusped (exponential), then so is the dark halo (An & Evans 2009). • The degeneracies in the Jeans equations are also illustrated by Walker et al.