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A Search for Ionized Gas in the Draco and Ursa Minor Dwarf Spheroidal Galaxies
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server A Search for Ionized Gas in the Draco and Ursa Minor Dwarf Spheroidal Galaxies J.S. Gallagher, G. J. Madsen, R. J. Reynolds Department of Astronomy, University of Wisconsin–Madison, 475 North Charter Street, Madison, WI 53706-1582; [email protected], [email protected], [email protected] E. K. Grebel Max-Planck Institute for Astronomy, K¨onigstuhl 17, D-69117 Heidelberg, Germany; [email protected] T. A. Smecker-Hane Department of Physics & Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697-4575; [email protected] ABSTRACT The Wisconsin Hα Mapper has been used to set the first deep upper limits on the intensity of diffuse Hα emission from warm ionized gas in the Draco and Ursa Minor dwarf spheroidal 1 galaxies. Assuming a velocity dispersion of 15 km s− for the ionized gas, we set limits of IHα 0:024R and IHα 0:021R for the Draco and Ursa Minor dSphs, respectively, averaged ≤ ≤ over our 1◦ circular beam. Adopting a simple model for the ionized interstellar medium, these limits translate to upper bounds on the mass of ionized gas of .10% of the stellar mass, or 10 times the upper limits for the mass of neutral hydrogen. Note that the Draco and Ursa Minor∼ dSphs could contain substantial amounts of interstellar gas, equivalent to all of the gas injected by dying stars since the end of their main star forming episodes &8 Gyr in the past, without violating these limits on the mass of ionized gas. -
Central Coast Astronomy Virtual Star Party May 15Th 7Pm Pacific
Central Coast Astronomy Virtual Star Party May 15th 7pm Pacific Welcome to our Virtual Star Gazing session! We’ll be focusing on objects you can see with binoculars or a small telescope, so after our session, you can simply walk outside, look up, and understand what you’re looking at. CCAS President Aurora Lipper and astronomer Kent Wallace will bring you a virtual “tour of the night sky” where you can discover, learn, and ask questions as we go along! All you need is an internet connection. You can use an iPad, laptop, computer or cell phone. When 7pm on Saturday night rolls around, click the link on our website to join our class. CentralCoastAstronomy.org/stargaze Before our session starts: Step 1: Download your free map of the night sky: SkyMaps.com They have it available for Northern and Southern hemispheres. Step 2: Print out this document and use it to take notes during our time on Saturday. This document highlights the objects we will focus on in our session together. Celestial Objects: Moon: The moon 4 days after new, which is excellent for star gazing! *Image credit: all astrophotography images are courtesy of NASA & ESO unless otherwise noted. All planetarium images are courtesy of Stellarium. Central Coast Astronomy CentralCoastAstronomy.org Page 1 Main Focus for the Session: 1. Canes Venatici (The Hunting Dogs) 2. Boötes (the Herdsman) 3. Coma Berenices (Hair of Berenice) 4. Virgo (the Virgin) Central Coast Astronomy CentralCoastAstronomy.org Page 2 Canes Venatici (the Hunting Dogs) Canes Venatici, The Hunting Dogs, a modern constellation created by Polish astronomer Johannes Hevelius in 1687. -
CO Multi-Line Imaging of Nearby Galaxies (COMING) IV. Overview Of
Publ. Astron. Soc. Japan (2018) 00(0), 1–33 1 doi: 10.1093/pasj/xxx000 CO Multi-line Imaging of Nearby Galaxies (COMING) IV. Overview of the Project Kazuo SORAI1, 2, 3, 4, 5, Nario KUNO4, 5, Kazuyuki MURAOKA6, Yusuke MIYAMOTO7, 8, Hiroyuki KANEKO7, Hiroyuki NAKANISHI9 , Naomasa NAKAI4, 5, 10, Kazuki YANAGITANI6 , Takahiro TANAKA4, Yuya SATO4, Dragan SALAK10, Michiko UMEI2 , Kana MOROKUMA-MATSUI7, 8, 11, 12, Naoko MATSUMOTO13, 14, Saeko UENO9, Hsi-An PAN15, Yuto NOMA10, Tsutomu, T. TAKEUCHI16 , Moe YODA16, Mayu KURODA6, Atsushi YASUDA4 , Yoshiyuki YAJIMA2 , Nagisa OI17, Shugo SHIBATA2, Masumichi SETA10, Yoshimasa WATANABE4, 5, 18, Shoichiro KITA4, Ryusei KOMATSUZAKI4 , Ayumi KAJIKAWA2, 3, Yu YASHIMA2, 3, Suchetha COORAY16 , Hiroyuki BAJI6 , Yoko SEGAWA2 , Takami TASHIRO2 , Miho TAKEDA6, Nozomi KISHIDA2 , Takuya HATAKEYAMA4 , Yuto TOMIYASU4 and Chey SAITA9 1Department of Physics, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 2Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 3Department of Physics, School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan 4Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan 5Tomonaga Center for the History of the Universe (TCHoU), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan 6Department of Physical Science, Osaka Prefecture University, Gakuen 1-1, -
Stellar Tidal Streams As Cosmological Diagnostics: Comparing Data and Simulations at Low Galactic Scales
RUPRECHT-KARLS-UNIVERSITÄT HEIDELBERG DOCTORAL THESIS Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Author: Referees: Gustavo MORALES Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL Astronomisches Rechen-Institut Heidelberg Graduate School of Fundamental Physics Department of Physics and Astronomy 14th May, 2018 ii DISSERTATION submitted to the Combined Faculties of the Natural Sciences and Mathematics of the Ruperto-Carola-University of Heidelberg, Germany for the degree of DOCTOR OF NATURAL SCIENCES Put forward by GUSTAVO MORALES born in Copiapo ORAL EXAMINATION ON JULY 26, 2018 iii Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Referees: Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL iv NOTE: Some parts of the written contents of this thesis have been adapted from a paper submitted as a co-authored scientific publication to the Astronomy & Astrophysics Journal: Morales et al. (2018). v NOTE: Some parts of this thesis have been adapted from a paper accepted for publi- cation in the Astronomy & Astrophysics Journal: Morales, G. et al. (2018). “Systematic search for tidal features around nearby galaxies: I. Enhanced SDSS imaging of the Local Volume". arXiv:1804.03330. DOI: 10.1051/0004-6361/201732271 vii Abstract In hierarchical models of galaxy formation, stellar tidal streams are expected around most galaxies. Although these features may provide useful diagnostics of the LCDM model, their observational properties remain poorly constrained. Statistical analysis of the counts and properties of such features is of interest for a direct comparison against results from numeri- cal simulations. In this work, we aim to study systematically the frequency of occurrence and other observational properties of tidal features around nearby galaxies. -
1. Introduction
THE ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 122:109È150, 1999 May ( 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. GALAXY STRUCTURAL PARAMETERS: STAR FORMATION RATE AND EVOLUTION WITH REDSHIFT M. TAKAMIYA1,2 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637; and Gemini 8 m Telescopes Project, 670 North Aohoku Place, Hilo, HI 96720 Received 1998 August 4; accepted 1998 December 21 ABSTRACT The evolution of the structure of galaxies as a function of redshift is investigated using two param- eters: the metric radius of the galaxy(Rg) and the power at high spatial frequencies in the disk of the galaxy (s). A direct comparison is made between nearby (z D 0) and distant(0.2 [ z [ 1) galaxies by following a Ðxed range in rest frame wavelengths. The data of the nearby galaxies comprise 136 broad- band images at D4500A observed with the 0.9 m telescope at Kitt Peak National Observatory (23 galaxies) and selected from the catalog of digital images of Frei et al. (113 galaxies). The high-redshift sample comprises 94 galaxies selected from the Hubble Deep Field (HDF) observations with the Hubble Space Telescope using the Wide Field Planetary Camera 2 in four broad bands that range between D3000 and D9000A (Williams et al.). The radius is measured from the intensity proÐle of the galaxy using the formulation of Petrosian, and it is argued to be a metric radius that should not depend very strongly on the angular resolution and limiting surface brightness level of the imaging data. It is found that the metric radii of nearby and distant galaxies are comparable to each other. -
The Denver Observer June 2016
The Denver JUNE 2016 OBSERVER Mercury transits the Sun on May 9, 2016. The planet, seen at the lower left of the Sun's face, has a diameter of about 3,000 miles, but the Sun's 870,000 mile cross-section dwarfs the planet—even though the Sun is seen here at twice Mercury's distance from us. (Note the planet-sized sunspots above-left of solar center.) Image © Ron Pearson. JUNE SKIES by Zachary Singer The Solar System the Martian surface reveals itself. On observing runs over the last few If you haven’t been observing Mars, the “unusually bright orange weeks, with good seeing, early views did indeed yield so-so results, but object in Libra,” now is a really good time: As June begins, the plan- improved noticeably as the planet neared its highest point in the south. et is just past opposition, and even more recently past its closest ap- I was able to make out the Syrtis Major region easily, even though proach to Earth, when the planet’s disk spanned a full 18.6 arcseconds. moonlight was a factor in the initial sessions. It looms large in a telescope now, and even instruments of moderate One great tool for power bring satisfying images at 100 or 150X. By midmonth, Mars improving your view Sky Calendar will be highest around 11 PM, with the disk slightly smaller, at 17.9”; is a “Moon filter.” 4 New Moon by June 30th, though, the planet will have already crossed the Meridian By bringing the sheer 12 First-Quarter Moon at 10 PM, before the sky brightness of Mars’ mag- 20 Full Moon In the Observer is fully dark, and the disk nitude -2 disk down a 27 Last-Quarter Moon will have shrunk some- notch, the moon filter President’s Message . -
HALOS, STARBURSTS, and SUPERBUBBLES in SPIRALS Joel
HALOS, STARBURSTS, AND SUPERBUBBLES IN SPIRALS Joel N. Bregman Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1090 [email protected] ABSTRACT Detectable quantities of interstellar material are present in the halo of the Milky Way galaxy and in a few edge-on spiral galaxies, largely in the form of neutral atomic gas, warm ionized material, and cosmic rays. Theoretical and observational arguments suggest that million degree gas should be present also, so sensitive ROSAT observations have been made of the large nearby edge- on spiral galaxies for the purpose of detecting hot extraplanar gas. Of the six brightest non-starburst edge-on galaxies, three exhibit extraplanar X-ray emission: NGC 891, NGC 4631, and NGC 4565. In NGC 891, the extended emission has a density scale height of 7 kpc and an extent along the disk of 13 kpc in diameter. This component is close to hydrostatic equilibrium, has a luminosity of 4.4 • 1039 erg s -1, and a mass of 10s Mo. Extended and structured extraplanar hot gas is seen around the interacting edge-on spiral NGC 4631, with X-ray emission associated with a giant loop of Ha and HI emission; spurs of X- ray emission extending from the disk are seen also. Hot gas is expected to enter the halo through superbubble breakout, and a search for superbubbles in normal spiral galaxies have shown that these phenomena are present, but of low surface brightness and are detected in only a few instances. Unlike the normal spiral galaxies where the gas is bound to the systems, the hot gas in starburst galaxies is being expelled. -
NGC-5466 Globular Cluster in Boötes Introduction the Purpose of the Observer’S Challenge Is to Encourage the Pursuit of Visual Observing
MONTHLY OBSERVER’S CHALLENGE Las Vegas Astronomical Society Compiled by: Roger Ivester, Boiling Springs, North Carolina & Fred Rayworth, Las Vegas, Nevada With special assistance from: Rob Lambert, Las Vegas, Nevada JUNE 2013 NGC-5466 Globular Cluster In Boötes Introduction The purpose of the observer’s challenge is to encourage the pursuit of visual observing. It is open to everyone that is interested, and if you are able to contribute notes, drawings, or photographs, we will be happy to include them in our monthly summary. Observing is not only a pleasure, but an art. With the main focus of amateur astronomy on astrophotography, many times people tend to forget how it was in the days before cameras, clock drives, and GOTO. Astronomy depended on what was seen through the eyepiece. Not only did it satisfy an innate curiosity, but it allowed the first astronomers to discover the beauty and the wonderment of the night sky. Before photography, all observations depended on what the astronomer saw in the eyepiece, and how they recorded their observations. This was done through notes and drawings and that is the tradition we are stressing in the observers challenge. By combining our visual observations with our drawings, and sometimes, astrophotography (from those with the equipment and talent to do so), we get a unique understanding of what it is like to look through an eyepiece, and to see what is really there. The hope is that you will read through these notes and become inspired to take more time at the eyepiece studying each object, and looking for those subtle details that you might never have noticed before. -
An Hα Kinematic Survey of Spiral and Irregular Galaxies – IV. 44 New Velocity fields
Mon. Not. R. Astron. Soc. 362, 127–166 (2005) doi:10.1111/j.1365-2966.2005.09274.x GHASP: an Hα kinematic survey of spiral and irregular galaxies – IV. 44 new velocity fields. Extension, shape and asymmetry of Hα rotation curves , O. Garrido,1 2 M. Marcelin,2 P. Amram,2 C. Balkowski,1 J. L. Gach2 and J. Boulesteix2 1Observatoire de Paris, section Meudon, GEPI, CNRS UMR 8111, Universite Paris 7, 5 Place Jules Janssen, 92195 Meudon, France 2 Observatoire Astronomique de Marseille Provence, Laboratoire d’Astrophysique de Marseille, 2 Place Le Verrier, 13248 Marseille Cedex 04 France Downloaded from https://academic.oup.com/mnras/article/362/1/127/1339746 by guest on 30 September 2021 Accepted 2005 June 3. Received 2005 May 26; in original form 2004 August 24 ABSTRACT We present Fabry–Perot observations obtained in the frame of the GHASP survey (Gassendi HAlpha survey of SPirals). We have derived the Hα map, the velocity field and the rotation curve for a new set of 44 galaxies. The data presented in this paper are combined with the data published in the three previous papers providing a total number of 85 of the 96 galaxies observed up to now. This sample of kinematical data has been divided into two groups: isolated (ISO) and softly interacting (SOFT) galaxies. In this paper, the extension of the Hα discs, the shape of the rotation curves, the kinematical asymmetry and the Tully–Fisher relation have been investigated for both ISO and SOFT galaxies. The Hα extension is roughly proportional to R25 for ISO as well as for SOFT galaxies. -
Upholding the Unified Model for Active Galactic Nuclei: VLT/FORS2 Spectropolarimetry of Seyfert 2 Galaxies
MNRAS 461, 1387–1403 (2016) doi:10.1093/mnras/stw1388 Advance Access publication 2016 June 9 Upholding the unified model for active galactic nuclei: VLT/FORS2 spectropolarimetry of Seyfert 2 galaxies C. Ramos Almeida,1,2‹† M. J. Mart´ınez Gonzalez,´ 1,2 A. Asensio Ramos,1,2 J. A. Acosta-Pulido,1,2 S. F. Honig,¨ 3 A. Alonso-Herrero,4,5 C. N. Tadhunter6 and O. Gonzalez-Mart´ ´ın7 1Instituto de Astrof´ısica de Canarias, Calle V´ıa Lactea,´ s/n, E-38205 La Laguna, Tenerife, Spain 2Departamento de Astrof´ısica, Universidad de La Laguna, E-38205 La Laguna, Tenerife, Spain 3School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK 4Centro de Astrobiolog´ıa (CAB, CSIC-INTA), ESAC Campus, E-28692 Villanueva de la Canada,˜ Madrid, Spain 5Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA 6Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK 7Instituto de Radioastronom´ıa y Astrof´ısica (IRAF-UNAM), 3-72 (Xangari), 8701 Morelia, Mexico Accepted 2016 June 7. Received 2016 June 7; in original form 2015 September 2 ABSTRACT The origin of the unification model for active galactic nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in ∼30–40 per cent of the nearby Sy2s observed to date. -
Does the Fornax Dwarf Spheroidal Have a Central Cusp Or Core?
Research Collection Journal Article Does the Fornax dwarf spheroidal have a central cusp or core? Author(s): Goerdt, Tobias; Moore, Ben; Read, J.I.; Stadel, Joachim; Zemp, Marcel Publication Date: 2006-05 Permanent Link: https://doi.org/10.3929/ethz-b-000024289 Originally published in: Monthly Notices of the Royal Astronomical Society 368(3), http://doi.org/10.1111/ j.1365-2966.2006.10182.x Rights / License: In Copyright - Non-Commercial Use Permitted This page was generated automatically upon download from the ETH Zurich Research Collection. For more information please consult the Terms of use. ETH Library Mon. Not. R. Astron. Soc. 368, 1073–1077 (2006) doi:10.1111/j.1365-2966.2006.10182.x Does the Fornax dwarf spheroidal have a central cusp or core? , Tobias Goerdt,1 Ben Moore,1 J. I. Read,1 Joachim Stadel1 and Marcel Zemp1 2 1Institute for Theoretical Physics, University of Zurich,¨ Winterthurerstrasse 190, CH-8057 Zurich,¨ Switzerland 2Institute of Astronomy, ETH Zurich,¨ ETH Honggerberg¨ HPF D6, CH-8093 Zurich,¨ Switzerland Accepted 2006 February 8. Received 2006 February 7; in original form 2005 December 21 ABSTRACT The dark matter dominated Fornax dwarf spheroidal has five globular clusters orbiting at ∼1 kpc from its centre. In a cuspy cold dark matter halo the globulars would sink to the centre from their current positions within a few Gyr, presenting a puzzle as to why they survive undigested at the present epoch. We show that a solution to this timing problem is to adopt a cored dark matter halo. We use numerical simulations and analytic calculations to show that, under these conditions, the sinking time becomes many Hubble times; the globulars effectively stall at the dark matter core radius. -
June 2013 BRAS Newsletter
www.brastro.org June 2013 What's in this issue: PRESIDENT'S MESSAGE .............................................................................................................................. 2 NOTES FROM THE VICE PRESIDENT ........................................................................................................... 3 MESSAGE FROM THE HRPO ...................................................................................................................... 4 OBSERVING NOTES ..................................................................................................................................... 6 MAY ASTRONOMICAL EVENTS .................................................................................................................... 9 PRESIDENT'S MESSAGE Greetings Everyone, Summer is here and with it the humidity and bugs, but I hope that won't stop you from getting out to see some of the great summer time objects in the sky. Also, Saturn is looking quite striking as the rings are now tilted at a nice angle allowing us to see the Casini Division and shadows on and from the planet. Don't miss it! I've been asked by BREC to make sure our club members are all aware of the Park Rules listed on BREC's website. Many of the rules are actually ordinances enacted by the city of Baton Rouge (e.g., No smoking permitted in public areas, No alcohol brought onto or sold on BREC property, No Gambling, No Firearms or Weapons, etc.) Please make sure you observe all of the Park Rules while at the HRPO and provide good examples for the general public. (Many of which are from outside East Baton Rouge Parish and are likely unaware of some of the policies.) For a full list of BREC's Park Rules, you may visit their Park Rules section of their website at http://brec.org/index.cfm/page/555/n/75 I'm sorry I had to miss the outing to LIGO, but it will be good to see some folks again at our meeting on Monday, June 10th.