Exploring the Galactic Center
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Nearby Dwarf Galaxies and Imbh Mini-Spikes
SF2A 2008 C. Charbonnel, F. Combes and R. Samadi (eds) DARK MATTER SEARCHES WITH H.E.S.S: NEARBY DWARF GALAXIES AND IMBH MINI-SPIKES Moulin, E.1, Vivier, M. 1 , Brun, P.1 , Glicenstein, J-F.1 and the H.E.S.S. Collaboration2 Abstract. WIMP pair annihilations produce high energy gamma-rays, which can be detected by IACTs such as the H.E.S.S. array of Imaging Atmospheric Cherenkov telescopes. Nearby dwarf galaxies and mini- spikes around intermediate-mass black holes (IMBHs) in the Galactic halo are possible targets for the ob- servation of these annihilations. H.E.S.S. observations on the nearby dwarf galaxy candidate Canis Major is reported. Using a modelling of the unknown dark matter density profile, constraints on the velocity-weighted annihilation cross section of DM particles are derived in the framework of Supersymmetric (pMSSM) and Kaluza-Klein (KK) models. Next, a search for DM mini-spikes around IMBHs is described and constraints on the particle physics parameters in various scenarios are given. 1 Introduction WIMPS (Weakly Interacting Massive Particles) are among the best motivated particle dark matter candidates. The WIMP annihilation rate is proportional to the square of the DM density integrated along the line of sight. Celestial objects with enhanced DM density are thus primary targets for indirect DM searches. Among these are the Galactic Center, nearby external galaxies and substructures in galactic haloes. In this paper, we report on H.E.S.S. results towards a dwarf galaxy candidate, Canis Major, and on a search for DM mini-spikes around IMBHs. -
The SOFIA Science and Mission Operations Center
A Publication of the Universities Space Research Association Summer 2005 Edition • www.usra.edu THE SOFIA SCIENCE AND MISSION OPERATIONS CENTER Hangar N211 at NASA Ames is Home of Airborne Astronomy Next year, the modified 747SP that is the Stratospheric Observatory For Infrared Astronomy will fly from Waco, Texas to Moffett Federal Airfield and the NASA Ames Research Center in California’s Santa Clara Valley. There, SOFIA will roll into its permanent new home: Hangar N211, the Above: Moffett Federal SOFIA Science Airfield and the NASA Ames and Mission Research Center. SOFIA’s Operations new home, Hangar N211 Center. Over the is highlighted. Dominating the landscape is Hangar last few years, One, built for the massive as the aircraft Navy airship USS Macon. has undergone Highway 101, connecting extensive San Francisco and San modifications Jose, cuts through right of photo. Water at upper left is that allow a southernmost fringe of the it to now San Francisco Bay. At left is accommodate a front view of N211. a 2.5-meter telescope in a vibration- isolated cavity that opens to the heavens, the building that Inside will house the aircraft and all associated operations 4 Hangar Floor Plan has been going through its own substantial 5 Why Moffett Field? alterations. In N211, the 6 Mirror Stripping and SOFIA aircraft will be Coating Rooms virtually surrounded by the people who make the missions happen – 8 SOFIA Team at Ames scientists, engineers, flight crews, mechanics, 9 Germans at the SSMOC education and outreach specialists, and database experts. The building also houses 9 Aircraft Update laboratories for readying and checking out instruments, facilities for stripping and coating the telescope’s primary mirror, flight operations rooms where missions 10 Preflight Integration Facility are planned, and education areas for students and teachers discovering airborne 10 SOFIA E/PO astronomy. -
Radio Observations of the Supermassive Black Hole at the Galactic Center and Its Orbiting Magnetar
Radio Observations of the Supermassive Black Hole at the Galactic Center and its Orbiting Magnetar Rebecca Rimai Diesing Honors Thesis Department of Physics and Astronomy Northwestern University Spring 2017 Honors Thesis Advisor: Farhad Zadeh ! Radio Observations of the Supermassive Black Hole at the Galactic Center and its Orbiting Magnetar Rebecca Rimai Diesing Department of Physics and Astronomy Northwestern University Honors Thesis Advisor: Farhad Zadeh Department of Physics and Astronomy Northwestern University At the center of our galaxy a bright radio source, Sgr A*, coincides with a black hole four million times the mass of our sun. Orbiting Sgr A* at a distance of 3 arc seconds (an estimated 0.1 pc) and rotating with a period of 3.76 s is a magnetar, or pulsar⇠ with an extremely strong magnetic field. This magnetar exhibited an X-ray outburst in April 2013, with enhanced, highly variable radio emission detected 10 months later. In order to better understand the behavior of Sgr A* and the magnetar, we study their intensity variability as a function of both time and frequency. More specifically, we present the results of short (8 minute) and long (7 hour) radio continuum observations, taken using the Jansky Very Large Array (VLA) over multiple epochs during the summer of 2016. We find that Sgr A*’s flux density (a proxy for intensity) is highly variable on an hourly timescale, with a frequency dependence that di↵ers at low (34 GHz) and high (44 GHz) frequencies. We also find that the magnetar remains highly variable on both short (8 min) and long (monthly) timescales, in agreement with observations from 2014. -
Astronomy and Astrophysics
THE DECADE OF DISCOVERY IN ASTRONOMY AND ASTROPHYSICS Astronomy and Astrophysics Survey Committee Board on Physics and Astronomy Commission on Physical Sciences, Mathematics, and Applications National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1991 NATIONAL ACADEMY PRESS • 2101 Constitution Avenue, NW • Washington, DC 20418 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special compe_nces and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. This project was supported by the Department of Energy under Grant No. DE-FGO5- 89ER40421, the National Aeronautics and Space Administration and the National Science Foundation under Grant No. AST-8901685, the Naval Research Laboratory under Contract No. N00173-90-M-9744, and the Smithsonian Institution under Purchase Order No. SF0022430000. Additional support was provided by the Maurice Ewing Earth and Planetary Sciences Fund of the National Academy of Sciences created through a gift from the Palisades Geophysical Institute, Inc., and an anonymous donor. Library of Congress Cataloging-in-Publication Data National Research Council (U.S.). Astronomy and Astrophysics Survey Committee. The decade of discovery in astronomy and astrophysics / Astronomy and Astrophysics Survey Committee, Board on Physics and Astronomy, Commission on Physical Sciences, Mathematics, and Applications, National Research Council. -
Early Science Opportunities with SOFIA IV: Introduction
SOFIA Community Task Force (SCTF) AAS Workshop Early Science Opportunities With SOFIA IV: Introduction Robert D. Gehrz Lead, SOFIA Community Task Force (SCTF) Department of Astronomy, University of Minnesota 1 R. D. Gehrz SCTF AAS Workshop IV, Pasadena, CA, June 7, 2009 Outline • The SOFIA Community Task Force (SCTF) • Mission of the SCTF • Activities of the SCTF • Agenda for “Early Scientific Opportunities with SOFIA IV” 2 R. D. Gehrz SCTF AAS Workshop IV, Pasadena, CA, June 7, 2009 The SOFIA Community Task Force (SCTF) - Members B-G Andersson: USRA SOFIA Dana Backman: SOFIA/SETI Institute Eric Becklin: USRA SOFIA, University of California Los Angeles David Black: Lunar and Planetary Institute Ed Erickson: SOFIA Bob Gehrz (Leader): University of Minnesota Matt Greenhouse: NASA GSFC Paul Hertz: NASA Headquarters Bob Joseph: University of Hawaii, Institute for Astronomy Dan Lester: University of Texas Margaret Meixner: STScI Pamela Marcum: NASA ARC Tom Roellig: NASA ARC Gran Sandell: SOFIA SI PI’s/designated representatives The SOFIA Science Team 3 R. D. Gehrz SCTF AAS Workshop IV, Pasadena, CA, June 7, 2009 The Mission of the SCTF The objectives of the Stratospheric Observatory for Infrared Astronomy (SOFIA) Community Task Force (SCTF) are to: • Inform the astronomical community about the status of the SOFIA Project and the science opportunities available through the General Investigator (GI) Program • Contribute to the development of a long-range science plan that will realize the potential of SOFIA as a premier observatory and as a -
October 2007 Volume 49 Issue 1 Dryden Flight Research Center
National Aeronautics and Space Administration Volume 49 Issue 1 Dryden Flight Research Center October 2007 National Aeronautics and Space Administration Sensational SOFIA News October 2007 The KeySOFIA events may lead to first science data in about 2 years By Jay Levine reduces the effects of the aircraft’s move- X-Press Editor ments during flight on the telescope as he Stratospheric Observatory well as reducing light reflection that could for Infrared Astronomy, or also impact it, he added. SOFIA made its debut at Some of the most extensive modifi- Dryden June 27 following cations include a 16-foot hole for the Tthree successful checkout flights in Waco, telescope door – the largest opening ever Texas, where major modifications had made on a 747 –and the re-routing of the been completed by L-3 Communications aircraft’s flight control cables to accom- Integrated Systems. modate the door. Those cables extend The arrival at Dryden marked a new to the vertical and horizontal control day in transitioning work with the aircraft surfaces. Flight control cables also will be from significant modification to the start instrumented to measure tension caused of flight tests, completion of subsystems by thermal expansion. Another key integration and, eventually, to the task of modification was addition of a bulkhead exploring the heavens. to reinforce the aircraft’s structure. The SOFIA still has a way to go before “It’s a tremendous accomplishment to routinely engaging in science flights. get the airplane here,” Carter said. “It’s Progress is measurable, however, and the result of some terrific collaboration flight tests that will validate the structural EC07 0105-31 NASA Photo by Tom Tschida among Ames, Dryden, the German modifications to the aircraft should begin Aerospace Center, L-3 Communications Above, members of the SOFIA program leadership include, from left, John Carter, Ed this fall, according to Bob Meyer, SOFIA Integrated Systems and the Universities Austin, Bob Meyer and Eric Becklin. -
Structure, Kinematics and Dynamics of the Galaxy
Outline Structure of the Galaxy Kinematics of the Galaxy Galactic dynamics STRUCTURE OF GALAXIES 1. Structure, kinematics and dynamics of the Galaxy Piet van der Kruit Kapteyn Astronomical Institute University of Groningen the Netherlands February 2010 Piet van der Kruit, Kapteyn Astronomical Institute Structure, kinematics and dynamics of the Galaxy Outline Structure of the Galaxy Kinematics of the Galaxy Galactic dynamics Outline Structure of the Galaxy History All-sky pictures Kinematics of the Galaxy Differential rotation Local approximations and Oort constants Rotation curves and mass distributions Galactic dynamics Fundamental equations Epicycle orbits Vertical motion Piet van der Kruit, Kapteyn Astronomical Institute Structure, kinematics and dynamics of the Galaxy Outline Structure of the Galaxy History Kinematics of the Galaxy All-sky pictures Galactic dynamics Structure of the Galaxy Piet van der Kruit, Kapteyn Astronomical Institute Structure, kinematics and dynamics of the Galaxy Outline Structure of the Galaxy History Kinematics of the Galaxy All-sky pictures Galactic dynamics History Our Galaxy can be seen on the sky as the Milky Way, a band of faint light. Piet van der Kruit, Kapteyn Astronomical Institute Structure, kinematics and dynamics of the Galaxy Outline Structure of the Galaxy History Kinematics of the Galaxy All-sky pictures Galactic dynamics The earliest attempts to study the structure of the Milky Way Galaxy (the Sidereal System; really the whole universe) on a global scale were based on star counts. William Herschel (1738 – 1822) performed such “star gauges” and assumed that (1) all stars have equal intrinsic luminostities and (2) he could see stars out ot the edges of the system. -
Caltech 1970
Caltech Jan 1970-August 1970 Ian Glass ([email protected]) My move to Caltech was the beginning of my involvement with infrared astronomy which became the theme for the rest of my career and in which I feel I was able to make some significant contributions. The Move West My MIT appointment in x-ray astronomy came to an end in September 1969. I was hoping for a post-doc position at UC San Diego in Peterson’s x-ray group and was disappointed to find that he had been stringing me along because he had another candidate who he preferred and to whom he eventually gave the position. My former SM supervisor, Frank Scherb at the University of Wisconsin, had some money left over in a grant for stellar interferometry and supported me for two months. Mostly I was living free at the Agassiz Station of Harvard College Observatory and spending any clear nights with Jim Elliot on interferometry. I am not sure how the contact with Gerry Neugebauer was made but possibly it was through Eric Becklin who was then at the Smithsonian, having just left Caltech. He occasionally did some observational work at Agassiz. Neugebauer was interested in the possibilities for stellar interferometry in the infrared. I was offered a post-doc by Gerry (not to be pronounced Jerry!) and I headed West towards the end of December. Ironically, as I left Massachusetts it was at its most wintry beautiful. The sky was blue and the trees were covered with icicles glittering in the Sun. I spent Christmas with the Ogilvies in Washington and a couple of nights with Jim Elliot’s family in Columbus, Ohio. -
Making the Invisible Visible: a History of the Spitzer Infrared Telescope Facility (1971–2003)/ by Renee M
MAKING THE INVISIBLE A History of the Spitzer Infrared Telescope Facility (1971–2003) MONOGRAPHS IN AEROSPACE HISTORY, NO. 47 Renee M. Rottner MAKING THE INVISIBLE VISIBLE A History of the Spitzer Infrared Telescope Facility (1971–2003) MONOGRAPHS IN AEROSPACE HISTORY, NO. 47 Renee M. Rottner National Aeronautics and Space Administration Office of Communications NASA History Division Washington, DC 20546 NASA SP-2017-4547 Library of Congress Cataloging-in-Publication Data Names: Rottner, Renee M., 1967– Title: Making the invisible visible: a history of the Spitzer Infrared Telescope Facility (1971–2003)/ by Renee M. Rottner. Other titles: History of the Spitzer Infrared Telescope Facility (1971–2003) Description: | Series: Monographs in aerospace history; #47 | Series: NASA SP; 2017-4547 | Includes bibliographical references. Identifiers: LCCN 2012013847 Subjects: LCSH: Spitzer Space Telescope (Spacecraft) | Infrared astronomy. | Orbiting astronomical observatories. | Space telescopes. Classification: LCC QB470 .R68 2012 | DDC 522/.2919—dc23 LC record available at https://lccn.loc.gov/2012013847 ON THE COVER Front: Giant star Zeta Ophiuchi and its effects on the surrounding dust clouds Back (top left to bottom right): Orion, the Whirlpool Galaxy, galaxy NGC 1292, RCW 49 nebula, the center of the Milky Way Galaxy, “yellow balls” in the W33 Star forming region, Helix Nebula, spiral galaxy NGC 2841 This publication is available as a free download at http://www.nasa.gov/ebooks. ISBN 9781626830363 90000 > 9 781626 830363 Contents v Acknowledgments -
Galactic Rotation II
1 Galactic Rotation • See SG 2.3, BM ch 3 B&T ch 2.6,2.7 B&T fig 1.3 and ch 6 • Coordinate system: define velocity vector by π,θ,z π radial velocity wrt galactic center θ motion tangential to GC with positive values in direct of galactic rotation z motion perpendicular to the plane, positive values toward North If the galaxy is axisymmetric galactic pole and in steady state then each pt • origin is the galactic center (center or in the plane has a velocity mass/rotation) corresponding to a circular • Local standard of rest (BM pg 536) velocity around center of mass • velocity of a test particle moving in of MW the plane of the MW on a closed orbit that passes thru the present position of (π,θ,z)LSR=(0,θ0,0) with 2 the sun θ0 =θ0(R) Coordinate Systems The stellar velocity vectors are z:velocity component perpendicular to plane z θ: motion tangential to GC with positive velocity in the direction of rotation radial velocity wrt to GC b π: GC π With respect to galactic coordinates l +π= (l=180,b=0) +θ= (l=30,b=0) +z= (b=90) θ 3 Local standard of rest: assume MW is axisymmetric and in steady state If this each true each point in the pane has a 'model' velocity corresponding to the circular velocity around of the center of mass. An imaginery point moving with that velocity at the position of the sun is defined to be the LSR (π,θ,z)LSR=(0,θ0,0);whereθ0 = θ0(R0) 4 Description of Galactic Rotation (S&G 2.3) • For circular motion: relative angles and velocities observing a distant point • T is the tangent point V =R sinl(V/R-V /R ) r 0 0 0 Vr Because V/R drops with R (rotation curve is ~flat); for value 0<l<90 or 270<l<360 reaches a maximum at T max So the process is to find Vr for each l and deduce V(R) =Vr+R0sinl For R>R0 : rotation curve from HI or CO is degenerate ; use masers, young stars with known distances 5 Galactic Rotation- S+G sec 2.3, B&T sec 3.2 • Consider a star in the midplane of the Galactic disk with Galactic longitude, l, at a distance d, from the Sun. -
The Galactic Center Environment
July 26, 1996 9:18 Annual Reviews Chapter16 AR12-16 Annu. Rev. Astron. Astrophys. 1996. 34:645–701 Copyright c 1996 by Annual Reviews Inc. All rights reserved THE GALACTIC CENTER ENVIRONMENT Mark Morris University of California at Los Angeles, Los Angeles, California 90095-1562 Eugene Serabyn California Institute of Technology, Pasadena, California 91125 KEY WORDS: Galactic bar, magnetic fields, SgrA∗, circumnuclear disk, star formation, molecular clouds, black holes, X rays ABSTRACT The central half kiloparsec region of our Galaxy harbors a variety of phenomena unique to the central environment. This review discusses the observed structure and activity of the interstellar medium in this region in terms of its inevitable inflow toward the center of the Galactic gravitational potential well. A number of dissipative processes lead to a strong concentration of gas into a “Central Molecular Zone” of about 200-pc radius, in which the molecular medium is characterized by large densities, large velocity dispersions, high temperatures, and apparently strong magnetic fields. The physical state of the gas and the resultant star formation processes occurring in this environment are therefore quite unlike those occurring in the large-scale disk. Gas not consumed by star formation either enters a hot X ray–emitting halo and is lost as a thermally driven galactic wind or continues moving inward, probably discontinuously, through the domain of the few parsec-sized circumnuclear disks and eventually into the central parsec. There, the central radio source SgrA currently accepts only a tiny Access provided by California Institute of Technology on 10/20/16. For personal use only. -
Identifying Candidate Young Stellar Objects in the Spider Nebula (IC 417) Using Archival Visible and Infrared Data
Identifying Candidate Young Stellar Objects in the Spider Nebula (IC 417) Using Archival Visible and Infrared Data Robert Anderson, JL Mann High School, Greenville, SC Brandon Rodriguez, Crescenta Valley High School, La Crescenta, CA Benjamin J. Senson, Madison College & James Madison Memorial High School, Madison, WI Mentor teacher: Vin Urbanowski, Academy of Information Technology & Engineering, Stamford, CT Mentor Astronomer: Luisa Rebull, IPAC, Caltech, Pasadena, CA 1.0 Abstract The Spider Nebula (IC 417) is a star-forming region about 2.3 kpc away, in the direction of the Galactic anti-center. While not in the outer reaches of the Galaxy by any means, IC 417 is still further towards the outer reaches of the Galaxy than most of the well- studied star-forming regions. If star formation there is significantly different from star formation elsewhere (perhaps due to metallicity or stellar density), it might manifest in a different distribution of masses (initial mass function). The first step to understanding whether star formation is different there is to take an inventory of the cluster member stars. We will be working towards a complete list of members of IC 417. This region was studied by a NITARP team in 2015, and we are continuing and enhancing their investigation, adding new data released after their work, most notably Gaia DR2 and PanSTARRS. Between the prior NITARP team and the rest of the literature, there are several hundred known young stellar objects (YSOs) and candidate YSOs. There is a somewhat overlooked portion of IC 417 called the Nebulous Stream (NS) that is most obvious in the mid-IR (3.6, 4.5 μm).