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Astronomie in Theorie Und Praxis 8. Auflage in Zwei Bänden Erik Wischnewski
Astronomie in Theorie und Praxis 8. Auflage in zwei Bänden Erik Wischnewski Inhaltsverzeichnis 1 Beobachtungen mit bloßem Auge 37 Motivation 37 Hilfsmittel 38 Drehbare Sternkarte Bücher und Atlanten Kataloge Planetariumssoftware Elektronischer Almanach Sternkarten 39 2 Atmosphäre der Erde 49 Aufbau 49 Atmosphärische Fenster 51 Warum der Himmel blau ist? 52 Extinktion 52 Extinktionsgleichung Photometrie Refraktion 55 Szintillationsrauschen 56 Angaben zur Beobachtung 57 Durchsicht Himmelshelligkeit Luftunruhe Beispiel einer Notiz Taupunkt 59 Solar-terrestrische Beziehungen 60 Klassifizierung der Flares Korrelation zur Fleckenrelativzahl Luftleuchten 62 Polarlichter 63 Nachtleuchtende Wolken 64 Haloerscheinungen 67 Formen Häufigkeit Beobachtung Photographie Grüner Strahl 69 Zodiakallicht 71 Dämmerung 72 Definition Purpurlicht Gegendämmerung Venusgürtel Erdschattenbogen 3 Optische Teleskope 75 Fernrohrtypen 76 Refraktoren Reflektoren Fokus Optische Fehler 82 Farbfehler Kugelgestaltsfehler Bildfeldwölbung Koma Astigmatismus Verzeichnung Bildverzerrungen Helligkeitsinhomogenität Objektive 86 Linsenobjektive Spiegelobjektive Vergütung Optische Qualitätsprüfung RC-Wert RGB-Chromasietest Okulare 97 Zusatzoptiken 100 Barlow-Linse Shapley-Linse Flattener Spezialokulare Spektroskopie Herschel-Prisma Fabry-Pérot-Interferometer Vergrößerung 103 Welche Vergrößerung ist die Beste? Blickfeld 105 Lichtstärke 106 Kontrast Dämmerungszahl Auflösungsvermögen 108 Strehl-Zahl Luftunruhe (Seeing) 112 Tubusseeing Kuppelseeing Gebäudeseeing Montierungen 113 Nachführfehler -
The Puzzle of the Strange Galaxy Made of 99.9% Dark Matter Is Solved 13 October 2020
The puzzle of the strange galaxy made of 99.9% dark matter is solved 13 October 2020 The galaxy Dragonfly 44 was discovered in a deep survey of the Coma cluster, a cluster with several thousand galaxies. From the start, the galaxy was considered remarkable by the researchers because the quantity of dark matter they inferred was almost as much as that in the Milky Way, the equivalent of a billion solar masses. However, instead of containing around a hundred thousand million stars, as has the Milky Way, DF44 has only a hundred million stars, a thousand times Image and amplification (in color) of the ultra-diffuse fewer. This means that the amount of dark matter galaxy Dragonfly 44 taken with the Hubble space was ten thousand times greater than that of its telescope. Credit: Teymoor Saifollahi and NASA/HST. stars. If this had been true, it would have been a unique object, with almost 100 times as much dark matter as that expected from the number of its stars. At present, the formation of galaxies is difficult to understand without the presence of a ubiquitous, Nevertheless, by an exhaustive analysis of the but mysterious component, termed dark matter. system of globular cluster around Dragonfly 44, the Astronomers have measure how much dark matter researchers have detected that the total number of there is around galaxies, and have found that it globular clusters is only 20, and that the total varies between 10 and 300 times the quantity of quantity of dark matter is around 300 times that of visible matter. -
A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra
San Jose State University From the SelectedWorks of Aaron J. Romanowsky 2016 A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra-Diffuse Galaxy Dragonfly 44 Pieter van Dokkum, Yale University Roberto Abraham, University of Toronto Jean P. Brodie, University of California Observatories Charlie Conroy, Harvard-Smithsonian Center for Astrophysics Shany Danieli, Yale University, et al. Available at: https://works.bepress.com/aaron_romanowsky/117/ The Astrophysical Journal Letters, 828:L6 (6pp), 2016 September 1 doi:10.3847/2041-8205/828/1/L6 © 2016. The American Astronomical Society. All rights reserved. A HIGH STELLAR VELOCITY DISPERSION AND ∼100 GLOBULAR CLUSTERS FOR THE ULTRA-DIFFUSE GALAXY DRAGONFLY 44 Pieter van Dokkum1, Roberto Abraham2, Jean Brodie3, Charlie Conroy4, Shany Danieli1, Allison Merritt1, Lamiya Mowla1, Aaron Romanowsky3,5, and Jielai Zhang2 1 Astronomy Department, Yale University, New Haven, CT 06511, USA 2 Department of Astronomy & Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada 3 University of California Observatories, 1156 High Street, Santa Cruz, CA 95064, USA 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, USA 5 Department of Physics and Astronomy, San José State University, San Jose, CA 95192, USA Received 2016 June 20; revised 2016 July 14; accepted 2016 July 15; published 2016 August 25 ABSTRACT Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival of these ultra-diffuse galaxies (UDGs) in a rich cluster suggests that they have very high masses. Here, we present the stellar kinematics of Dragonfly44, one of the largest Coma UDGs, using a 33.5 hr fi +8 -1 integration with DEIMOS on the Keck II telescope. -
Spatially Resolved Stellar Kinematics of the Ultra-Diffuse Galaxy Dragonfly 44
The Astrophysical Journal, 880:91 (26pp), 2019 August 1 https://doi.org/10.3847/1538-4357/ab2914 © 2019. The American Astronomical Society. All rights reserved. Spatially Resolved Stellar Kinematics of the Ultra-diffuse Galaxy Dragonfly 44. I. Observations, Kinematics, and Cold Dark Matter Halo Fits Pieter van Dokkum1 , Asher Wasserman2 , Shany Danieli1 , Roberto Abraham3 , Jean Brodie2 , Charlie Conroy4 , Duncan A. Forbes5, Christopher Martin6, Matt Matuszewski6, Aaron J. Romanowsky2,7 , and Alexa Villaume2 1 Astronomy Department, Yale University, 52 Hillhouse Avenue, New Haven, CT 06511, USA 2 University of California Observatories, 1156 High Street, Santa Cruz, CA 95064, USA 3 Department of Astronomy & Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, USA 5 Centre for Astrophysics and Supercomputing, Swinburne University, Hawthorn, VIC 3122, Australia 6 Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Mail Code 278-17, Pasadena, CA 91125, USA 7 Department of Physics and Astronomy, San José State University, San Jose, CA 95192, USA Received 2019 March 31; revised 2019 May 25; accepted 2019 June 5; published 2019 July 30 Abstract We present spatially resolved stellar kinematics of the well-studied ultra-diffuse galaxy (UDG) Dragonfly44, as determined from 25.3 hr of observations with the Keck Cosmic Web Imager. The luminosity-weighted dispersion +3 −1 within the half-light radius is s12= 33-3 km s , lower than what we had inferred before from a DEIMOS spectrum in the Hα region. There is no evidence for rotation, with Vmax áñ<s 0.12 (90% confidence) along the major axis, in possible conflict with models where UDGs are the high-spin tail of the normal dwarf galaxy distribution. -
The Maunder Minimum and the Variable Sun-Earth Connection
The Maunder Minimum and the Variable Sun-Earth Connection (Front illustration: the Sun without spots, July 27, 1954) By Willie Wei-Hock Soon and Steven H. Yaskell To Soon Gim-Chuan, Chua Chiew-See, Pham Than (Lien+Van’s mother) and Ulla and Anna In Memory of Miriam Fuchs (baba Gil’s mother)---W.H.S. In Memory of Andrew Hoff---S.H.Y. To interrupt His Yellow Plan The Sun does not allow Caprices of the Atmosphere – And even when the Snow Heaves Balls of Specks, like Vicious Boy Directly in His Eye – Does not so much as turn His Head Busy with Majesty – ‘Tis His to stimulate the Earth And magnetize the Sea - And bind Astronomy, in place, Yet Any passing by Would deem Ourselves – the busier As the Minutest Bee That rides – emits a Thunder – A Bomb – to justify Emily Dickinson (poem 224. c. 1862) Since people are by nature poorly equipped to register any but short-term changes, it is not surprising that we fail to notice slower changes in either climate or the sun. John A. Eddy, The New Solar Physics (1977-78) Foreword By E. N. Parker In this time of global warming we are impelled by both the anticipated dire consequences and by scientific curiosity to investigate the factors that drive the climate. Climate has fluctuated strongly and abruptly in the past, with ice ages and interglacial warming as the long term extremes. Historical research in the last decades has shown short term climatic transients to be a frequent occurrence, often imposing disastrous hardship on the afflicted human populations. -
X-Ray Emission from a Merger Remnant, NGC 7252,The “Atoms-For-Peace” Galaxy
X-ray emission from a merger remnant, NGC 7252,the \Atoms-for-Peace" galaxy Hisamitsu Awaki Department of Physics, Faculty of Science, Ehime University Hironori Matsumoto1 Department of Earth and Space Science, Osaka University, and Hiroshi Tomida Space Utilization Research Program, National Space Development Agency of Japan, ABSTRACT We observed a nearby merger remnant NGC 7252 with the X-ray satellite ASCA, 13 1 2 and detected X-ray emission with the X-ray flux of (1.8 0.3) 10− ergs s− cm− in ± × 40 1 the 0.5–10 keV band. This corresponds to the X-ray luminosity of 8.1 10 ergs s− . The X-ray emission is well described with a two-component model: a soft× component with kT =0:72 0.13 keV and a hard component with kT > 5:1 keV. Although NGC 7252 is referred± to as a dynamically young protoelliptical, the 0.5–4 keV luminosity of 40 1 the soft component is about 2 10 ergs s− , which is low for an early-type galaxy. The × ratio of LX=LFIR suggests that the soft component originated from the hot gas due to star formation. Its low luminosity can be explained by the gas ejection from the galaxy as galaxy winds. Our observation reveals the existence of hard X-ray emission with the 40 1 2–10 keV luminosity of 5.6 10 ergs s− . This may indicate the existence of nuclear activity or intermediate-mass× black hole in NGC 7252. Subject headings: galaxies: evolution — galaxies: individual (NGC 7252) — X-rays: galaxies 1Center for Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, NE80-6045, Cambridge, MA02139-4307, USA 1 1. -
Understanding the H2/HI Ratio in Galaxies 3
Mon. Not. R. Astron. Soc. 394, 1857–1874 (2009) Printed 6 August 2021 (MN LATEX style file v2.2) Understanding the H2/HI Ratio in Galaxies D. Obreschkow and S. Rawlings Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH, UK Accepted 2009 January 12 ABSTRACT galaxy We revisit the mass ratio Rmol between molecular hydrogen (H2) and atomic hydrogen (HI) in different galaxies from a phenomenological and theoretical viewpoint. First, the local H2- mass function (MF) is estimated from the local CO-luminosity function (LF) of the FCRAO Extragalactic CO-Survey, adopting a variable CO-to-H2 conversion fitted to nearby observa- 5 1 tions. This implies an average H2-density ΩH2 = (6.9 2.7) 10− h− and ΩH2 /ΩHI = 0.26 0.11 ± · galaxy ± in the local Universe. Second, we investigate the correlations between Rmol and global galaxy properties in a sample of 245 local galaxies. Based on these correlations we intro- galaxy duce four phenomenological models for Rmol , which we apply to estimate H2-masses for galaxy each HI-galaxy in the HIPASS catalog. The resulting H2-MFs (one for each model for Rmol ) are compared to the reference H2-MF derived from the CO-LF, thus allowing us to determine the Bayesian evidence of each model and to identify a clear best model, in which, for spi- galaxy ral galaxies, Rmol negatively correlates with both galaxy Hubble type and total gas mass. galaxy Third, we derive a theoretical model for Rmol for regular galaxies based on an expression for their axially symmetric pressure profile dictating the degree of molecularization. -
1987Apj. . .320. .2383 the Astrophysical Journal, 320:238-257
.2383 The Astrophysical Journal, 320:238-257,1987 September 1 © 1987. The American Astronomical Society. AU rights reserved. Printed in U.S.A. .320. 1987ApJ. THE IRÁS BRIGHT GALAXY SAMPLE. II. THE SAMPLE AND LUMINOSITY FUNCTION B. T. Soifer, 1 D. B. Sanders,1 B. F. Madore,1,2,3 G. Neugebauer,1 G. E. Danielson,4 J. H. Elias,1 Carol J. Lonsdale,5 and W. L. Rice5 Received 1986 December 1 ; accepted 1987 February 13 ABSTRACT A complete sample of 324 extragalactic objects with 60 /mi flux densities greater than 5.4 Jy has been select- ed from the IRAS catalogs. Only one of these objects can be classified morphologically as a Seyfert nucleus; the others are all galaxies. The median distance of the galaxies in the sample is ~ 30 Mpc, and the median 10 luminosity vLv(60 /mi) is ~2 x 10 L0. This infrared selected sample is much more “infrared active” than optically selected galaxy samples. 8 12 The range in far-infrared luminosities of the galaxies in the sample is 10 LQ-2 x 10 L©. The far-infrared luminosities of the sample galaxies appear to be independent of the optical luminosities, suggesting a separate luminosity component. As previously found, a correlation exists between 60 /¿m/100 /¿m flux density ratio and far-infrared luminosity. The mass of interstellar dust required to produce the far-infrared radiation corre- 8 10 sponds to a mass of gas of 10 -10 M0 for normal gas to dust ratios. This is comparable to the mass of the interstellar medium in most galaxies. -
Sodium and Potassium Signatures Of
Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets Apurva Oza, Robert Johnson, Emmanuel Lellouch, Carl Schmidt, Nick Schneider, Chenliang Huang, Diana Gamborino, Andrea Gebek, Aurelien Wyttenbach, Brice-Olivier Demory, et al. To cite this version: Apurva Oza, Robert Johnson, Emmanuel Lellouch, Carl Schmidt, Nick Schneider, et al.. Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets. The Astro- physical Journal, American Astronomical Society, 2019, 885 (2), pp.168. 10.3847/1538-4357/ab40cc. hal-02417964 HAL Id: hal-02417964 https://hal.sorbonne-universite.fr/hal-02417964 Submitted on 18 Dec 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. The Astrophysical Journal, 885:168 (19pp), 2019 November 10 https://doi.org/10.3847/1538-4357/ab40cc © 2019. The American Astronomical Society. Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets Apurva V. Oza1 , Robert E. Johnson2,3 , Emmanuel Lellouch4 , Carl Schmidt5 , Nick Schneider6 , Chenliang Huang7 , Diana Gamborino1 , Andrea Gebek1,8 , Aurelien Wyttenbach9 , Brice-Olivier Demory10 , Christoph Mordasini1 , Prabal Saxena11, David Dubois12 , Arielle Moullet12, and Nicolas Thomas1 1 Physikalisches Institut, Universität Bern, Bern, Switzerland; [email protected] 2 Engineering Physics, University of Virginia, Charlottesville, VA 22903, USA 3 Physics, New York University, 4 Washington Place, New York, NY 10003, USA 4 LESIA–Observatoire de Paris, CNRS, UPMC Univ. -
Downloads/ Astero2007.Pdf) and by Aerts Et Al (2010)
This work is protected by copyright and other intellectual property rights and duplication or sale of all or part is not permitted, except that material may be duplicated by you for research, private study, criticism/review or educational purposes. Electronic or print copies are for your own personal, non- commercial use and shall not be passed to any other individual. No quotation may be published without proper acknowledgement. For any other use, or to quote extensively from the work, permission must be obtained from the copyright holder/s. i Fundamental Properties of Solar-Type Eclipsing Binary Stars, and Kinematic Biases of Exoplanet Host Stars Richard J. Hutcheon Submitted in accordance with the requirements for the degree of Doctor of Philosophy. Research Institute: School of Environmental and Physical Sciences and Applied Mathematics. University of Keele June 2015 ii iii Abstract This thesis is in three parts: 1) a kinematical study of exoplanet host stars, 2) a study of the detached eclipsing binary V1094 Tau and 3) and observations of other eclipsing binaries. Part I investigates kinematical biases between two methods of detecting exoplanets; the ground based transit and radial velocity methods. Distances of the host stars from each method lie in almost non-overlapping groups. Samples of host stars from each group are selected. They are compared by means of matching comparison samples of stars not known to have exoplanets. The detection methods are found to introduce a negligible bias into the metallicities of the host stars but the ground based transit method introduces a median age bias of about -2 Gyr. -
FY13 High-Level Deliverables
National Optical Astronomy Observatory Fiscal Year Annual Report for FY 2013 (1 October 2012 – 30 September 2013) Submitted to the National Science Foundation Pursuant to Cooperative Support Agreement No. AST-0950945 13 December 2013 Revised 18 September 2014 Contents NOAO MISSION PROFILE .................................................................................................... 1 1 EXECUTIVE SUMMARY ................................................................................................ 2 2 NOAO ACCOMPLISHMENTS ....................................................................................... 4 2.1 Achievements ..................................................................................................... 4 2.2 Status of Vision and Goals ................................................................................. 5 2.2.1 Status of FY13 High-Level Deliverables ............................................ 5 2.2.2 FY13 Planned vs. Actual Spending and Revenues .............................. 8 2.3 Challenges and Their Impacts ............................................................................ 9 3 SCIENTIFIC ACTIVITIES AND FINDINGS .............................................................. 11 3.1 Cerro Tololo Inter-American Observatory ....................................................... 11 3.2 Kitt Peak National Observatory ....................................................................... 14 3.3 Gemini Observatory ........................................................................................ -
Investigating the Relation Between CO (3-2) and Far Infrared Luminosities
Publ. Astron. Soc. Japan (2014) 00(0), 1–16 1 doi: 10.1093/pasj/xxx000 Investigating the Relation between CO (3–2) and Far Infrared Luminosities for Nearby Merging Galaxies Using ASTE Tomonari MICHIYAMA,1,2 Daisuke IONO,1,2 Kouichiro NAKANISHI1,2 Junko UEDA,3 Toshiki SAITO,4,2 Misaki ANDO,1,2 Hiroyuki KANEKO,5,2 Takuji YAMASHITA,6 Yuichi MATSUDA,1,2 Bunyo HATSUKADE,2 Kenichi KIKUCHI,2 Shinya KOMUGI,7 and Takayuki MUTO7 1Department of Astronomical Science, SOKENDAI (The Graduate University of Advanced Studies), Mitaka, Tokyo 181-8588 2National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 3Harvard-Smithsonian Center for Astrophysics, 60 Garden Street,Cambridge, MA 02138, USA 4Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 133-0033 5Nobeyama Radio Observatory, 462-2, Minamimaki, Minamisaku, Nagano, 384-1305 6Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 7Division of Liberal Arts, Kogakuin University, 1-24-2, Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677 ∗E-mail: [email protected] Received ; Accepted Abstract We present the new single dish CO (3–2) emission data obtained toward 19 early stage and 7 late stage nearby merging galaxies using the Atacama Submillimeter Telescope Experiment (ASTE). Combining with the single dish and interferometric data of galaxies observed in pre- ′ vious studies, we investigate the relation between the CO (3–2) luminosity (LCO(3−2)) and the far Infrared luminosity (LFIR) in a sample of 29 early stage and 31 late stage merging galaxies, and 28 nearby isolated spiral galaxies.