Radio and Millimeter Continuum Surveys and Their Astrophysical Implications
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The Development of a Small Scale Radio Astronomy Image Synthesis Array for Research in Radio Frequency Interference Mitigation
Brigham Young University BYU ScholarsArchive Theses and Dissertations 2005-09-05 The Development of a Small Scale Radio Astronomy Image Synthesis Array for Research in Radio Frequency Interference Mitigation Jacob L. Campbell Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Electrical and Computer Engineering Commons BYU ScholarsArchive Citation Campbell, Jacob L., "The Development of a Small Scale Radio Astronomy Image Synthesis Array for Research in Radio Frequency Interference Mitigation" (2005). Theses and Dissertations. 673. https://scholarsarchive.byu.edu/etd/673 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. THE DEVELOPMENT OF A SMALL SCALE RADIO ASTRONOMY IMAGE SYNTHESIS ARRAY FOR RESEARCH IN RADIO FREQUENCY INTERFERENCE MITIGATION by Jacob Lee Campbell A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science Department of Electrical and Computer Engineering Brigham Young University December 2005 Copyright c 2005 Jacob Lee Campbell All Rights Reserved BRIGHAM YOUNG UNIVERSITY GRADUATE COMMITTEE APPROVAL of a thesis submitted by Jacob Lee Campbell This thesis has been read by each member of the following graduate committee and by majority vote has -
Information Bulletin on Variable Stars
COMMISSIONS AND OF THE I A U INFORMATION BULLETIN ON VARIABLE STARS Nos November July EDITORS L SZABADOS K OLAH TECHNICAL EDITOR A HOLL TYPESETTING K ORI ADMINISTRATION Zs KOVARI EDITORIAL BOARD L A BALONA M BREGER E BUDDING M deGROOT E GUINAN D S HALL P HARMANEC M JERZYKIEWICZ K C LEUNG M RODONO N N SAMUS J SMAK C STERKEN Chair H BUDAPEST XI I Box HUNGARY URL httpwwwkonkolyhuIBVSIBVShtml HU ISSN COPYRIGHT NOTICE IBVS is published on b ehalf of the th and nd Commissions of the IAU by the Konkoly Observatory Budap est Hungary Individual issues could b e downloaded for scientic and educational purp oses free of charge Bibliographic information of the recent issues could b e entered to indexing sys tems No IBVS issues may b e stored in a public retrieval system in any form or by any means electronic or otherwise without the prior written p ermission of the publishers Prior written p ermission of the publishers is required for entering IBVS issues to an electronic indexing or bibliographic system to o CONTENTS C STERKEN A JONES B VOS I ZEGELAAR AM van GENDEREN M de GROOT On the Cyclicity of the S Dor Phases in AG Carinae ::::::::::::::::::::::::::::::::::::::::::::::::::: : J BOROVICKA L SAROUNOVA The Period and Lightcurve of NSV ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::: W LILLER AF JONES A New Very Long Period Variable Star in Norma ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::: EA KARITSKAYA VP GORANSKIJ Unusual Fading of V Cygni Cyg X in Early November ::::::::::::::::::::::::::::::::::::::: -
The 1.4 Ghz Light Curve of GRB 970508
The 1.4 GHz light curve of GRB 970508 T.J. Galama1, R.A.M.J. Wijers2, M. Bremer3, P.J. Groot1, R.G. Strom1,4, A.G. de Bruyn4,5, C. Kouveliotou6,7, C.R. Robinson6,7, J. van Paradijs1,8 ABSTRACT We report on Westerbork 1.4 GHz radio observations of the radio counterpart to γ-ray burst GRB 970508, between 0.80 and 138 days after this event. The 1.4 GHz light curve shows a transition from optically thick to thin emission between 39 and 54 days after the event. We derive the slope p of the spectrum of injected ∝ −p electrons (dN/dγe γe ) in two independent ways which yield values very close to p = 2.2. This is in agreement with a relativistic dynamically near-adiabatic blast wave model whose emission is dominated by synchrotron radiation and in which a significant fraction of the electrons cool fast. Subject headings: gamma rays: bursts — gamma rays: individual (GRB 970508) — radio continuum: general 1. Introduction The peak luminosities of γ-ray bursts (GRBs) are highly super-Eddington and require relativistic outflows (Paczy´nski 1986; Goodman 1986). Paczy´nski and Rhoads (1993) pointed out that radio emission is expected as a result of the interaction between such arXiv:astro-ph/9804190v1 20 Apr 1998 1Astronomical Institute ‘Anton Pannekoek’, University of Amsterdam, & Center for High Energy Astrophysics, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands 2Institute of Astronomy, Madingley Road, Cambridge, UK 3Institut de Radio Astronomie Millim´etrique, 300 rue de la Piscine, F–38406 Saint-Martin d’H`eres, France 4NFRA, Postbus 2, 7990 AA Dwingeloo, The Netherlands 5Kapteyn Astronomical Institute, Postbus 800, 9700 AV, Groningen, The Netherlands 6Universities Space Research Asociation 7NASA/MSFC, Code ES-84, Huntsville AL 35812, USA 8Physics Department, University of Alabama in Huntsville, Huntsville AL 35899, USA –2– a relativistic outflow and an external medium, as is, e.g., observed in extragalactic jet sources (see also Katz 1994; M´esz´aros and Rees 1997). -
Small-Scale Anisotropies of the Cosmic Microwave Background: Experimental and Theoretical Perspectives
Small-Scale Anisotropies of the Cosmic Microwave Background: Experimental and Theoretical Perspectives Eric R. Switzer A DISSERTATION PRESENTED TO THE FACULTY OF PRINCETON UNIVERSITY IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY RECOMMENDED FOR ACCEPTANCE BY THE DEPARTMENT OF PHYSICS [Adviser: Lyman Page] November 2008 c Copyright by Eric R. Switzer, 2008. All rights reserved. Abstract In this thesis, we consider both theoretical and experimental aspects of the cosmic microwave background (CMB) anisotropy for ℓ > 500. Part one addresses the process by which the universe first became neutral, its recombination history. The work described here moves closer to achiev- ing the precision needed for upcoming small-scale anisotropy experiments. Part two describes experimental work with the Atacama Cosmology Telescope (ACT), designed to measure these anisotropies, and focuses on its electronics and software, on the site stability, and on calibration and diagnostics. Cosmological recombination occurs when the universe has cooled sufficiently for neutral atomic species to form. The atomic processes in this era determine the evolution of the free electron abundance, which in turn determines the optical depth to Thomson scattering. The Thomson optical depth drops rapidly (cosmologically) as the electrons are captured. The radiation is then decoupled from the matter, and so travels almost unimpeded to us today as the CMB. Studies of the CMB provide a pristine view of this early stage of the universe (at around 300,000 years old), and the statistics of the CMB anisotropy inform a model of the universe which is precise and consistent with cosmological studies of the more recent universe from optical astronomy. -
On the Hunt for Excited States
INTERNATIONAL JOURNAL OF HIGH-ENERGY PHYSICS CERN COURIER VOLUME 45 NUMBER 10 DECEMBER 2005 On the hunt for excited states HOMESTAKE DARK MATTER SNOWMASS Future assured for Galactic gamma rays US workshop gets underground lab p5 may hold the key p 17 ready for the ILC p24 www.vectorfields.comi Music to your ears 2D & 3D electromagnetic modellinj If you're aiming for design excellence, demanding models. As a result millions you'll be pleased to hear that OPERA, of elements can be solved in minutes, the industry standard for electromagnetic leaving you to focus on creating modelling, gives you the most powerful outstanding designs. Electron trajectories through a TEM tools for engineering and scientific focussing stack analysis. Fast, accurate model analysis • Actuators and sensors - including Designed for parameterisation and position and NDT customisation, OPERA is incredibly easy • Magnets - ppm accuracy using TOSCA to use and has an extensive toolset, making • Electron devices - space charge analysis it ideal for a wide range of applications. including emission models What's more, its high performance analysis • RF Cavities - eigen modes and single modules work at exceptional levels of speed, frequency response accuracy and stability, even with the most • Motors - dynamic analysis including motion Don't take our word for it - order your free trial and check out OPERA yourself. B-field in a PMDC motor Vector Fields Ltd Culham Science Centre, Abingdon, Oxon, 0X14 3ED, U.K. Tel: +44 (0)1865 370151 Fax: +44 (0)1865 370277 Email: [email protected] Vector Fields Inc 1700 North Famsworth Avenue, Aurora, IL, 60505. -
The Very Small Array
The Very Small Array Project: VSA PI: Dr. H. Paul Shuch, Exec. Dir., The SETI League, Inc. ([email protected]) Description and Objectives: A test platform for future research-grade radio telescopes, the Very Small Array is a low-cost effort to combine the collecting area of multiple off-the-shelf backyard satellite TV dishes into a highly capable L-band observing instrument. A volunteer effort of the grassroots nonprofit SETI League, the VSA is being built in the Principal Investigator’s backyard, with member donations and modest grant funding. A US patent has been issued for our technique of employing combined analog and digital circuitry for simultaneous total power radiometry, spectroscopy, and aperture synthesis interferometry. Key Features of Instrument: Schedule Milestones: Phase 0: Paper design, single-dish test bed; § 8 ea. 1.8 meter reflectors in Mills Cross array US patent #6,593,876 (issued 2003) § Offset feeds for non-blocked aperture Phase 1: Physical Structures – (completed 2004) (masts, az/el mounts, dishes, feeds, § Meridian transit mode w/ elevation rotation conduit, junction boxes cables) § Dual Orthogonal Circular Polarizations Phase 2: Front-end electronics (in process 2005) Phase 3: Back-end electronics + DSP (planned for 2007) § Full ‘water-hole’ coverage, 1.2 – 1.7 GHz Applications: § Simultaneous total power radiometry, spec- § Meridian transit all-sky SETI survey troscopy, and interferometry in real time § Parasitic Astrophysical Survey § Targeted SETI in direction of known exoplanets Partners: § Quick-response verification of candidate SETI signals American Astronomical Society, ARRL TRL = 3 Foundation, Microcomm Consulting Revised: 12 May 2005 Keywords: Radio Telescope, Phased Array, Mills Cross, Radiometry, Spectroscopy, Interferometry, SETI. -
ASTRONOMY and ASTROPHYSICS BV Rcic Photometry of GRB 970508
Astron. Astrophys. 334, 117–123 (1998) ASTRONOMY AND ASTROPHYSICS BV RcIc photometry of GRB 970508 optical remnant: May-August, 1997 V.V. Sokolov1, A.I. Kopylov1, S.V. Zharikov1, M. Feroci2, L. Nicastro3, and E. Palazzi3 1 Special Astrophysical Observatory of RAS, Karachai-Cherkessia, 357147 Nizhnij Arkhyz Russia (sokolov,akop,[email protected]) 2 Istituto di Astrofisica Spaziale, CNR, Via Fosso del Cavaliere, I-00131 Roma, Italy 3 Istituto Tecnologie e Studio Radiazioni Extraterrestri CNR, Via P. Gobetti 101, I-40129 Bologna, Italy Received 2 February 1998 / Accepted 24 February 1998 Abstract. We present the results of photometric observations Thank to the fast and accurate positioning of GRBs (a few ar- of the variable optical source associated to the remnant of the cminutes) obtainable through the combined capabilities of the gamma-ray burst GRB 970508 performed at the Special As- Gamma-Ray Burst Monitor (GRBM) and Wide Field Cameras trophysical Observatory of the Russian Academy of Science (WFCs) onboard this satellite, an X-ray and optical afterglow (SAO RAS) from May to August 1997. The observations were were observed for the very first time (Costa et al. 1997b, van carried out with the standard (Johnson-Kron-Cousins) photo- Paradijs et al., 1997). metric BV RcIc system using the 1-meter and 6-meter tele- However, as was found out later, the optical data on the first scopes. The brightness of the optical source increased from GRB afterglow in the history were obtained with different in- Rc =21.19 ± 0.25 (May 9.75 UT) to Rc =19.70 ± 0.03 struments and in different photometric conditions and refer to (May 10.77 UT), whereupon it was decaying in all the four different photometric systems and bands. -
Mobberley.Pdf
September 18, 2008 Time: 7:31am t1-v1.0 Cataclysmic Cosmic Events and How to Observe Them For other titles published in this series, go to www.springer.com/series/5338 September 18, 2008 Time: 7:31am t1-v1.0 Martin Mobberley Cataclysmic Cosmic Events and How to Observe Them 13 September 18, 2008 Time: 7:31am t1-v1.0 Martin Mobberley Suffolk, UK e-mail: [email protected] ISBN: 978-0-387-79945-2 e-ISBN: 978-0-387-79946-9 DOI: 10.1007/978-0-387-79946-9 Library of Congress Control Number: 2008920267 # Springer ScienceþBusiness Media, LLC 2009 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer ScienceþBusiness Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper springer.com Acknowledgements As was the case with my five previous Springer books, I am indebted to my fellow amateurs who have generously donated pictures of themselves, and images of their results, to this project. I am especially indebted to Seiichiro Kiyota for his con- siderable help in contacting Japanese nova patrollers who donated images of themselves for Chapter 2. -
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A&A 533, A57 (2011) Astronomy DOI: 10.1051/0004-6361/201116972 & c ESO 2011 Astrophysics High-frequency predictions for number counts and spectral properties of extragalactic radio sources. New evidence of a break at mm wavelengths in spectra of bright blazar sources M. Tucci1,L.Toffolatti2,3, G. De Zotti4,5, and E. Martínez-González6 1 LAL, Univ Paris-Sud, CNRS/IN2P3, Orsay, France e-mail: [email protected] 2 Departamento de Física, Universidad de Oviedo, c. Calvo Sotelo s/n, 33007 Oviedo, Spain 3 Research Unit associated with IFCA-CSIC, Instituto de Física de Cantabria, avda. los Castros, s/n, 39005 Santander, Spain 4 INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy 5 International School for Advanced Studies, SISSA/ISAS, Astrophysics Sector, via Bonomea 265, 34136 Trieste, Italy 6 Instituto de Física de Cantabria, CSIC-Universidad de Cantabria, Avda. de los Castros s/n, 39005 Santander, Spain Received 28 March 2011 / Accepted 9 June 2011 ABSTRACT We present models to predict high-frequency counts of extragalactic radio sources using physically grounded recipes to describe the complex spectral behaviour of blazars that dominate the mm-wave counts at bright flux densities. We show that simple power-law spectra are ruled out by high-frequency (ν ≥ 100 GHz) data. These data also strongly constrain models featuring the spectral breaks predicted by classical physical models for the synchrotron emission produced in jets of blazars. A model dealing with blazars as a single population is, at best, only marginally consistent with data coming from current surveys at high radio frequencies. -
SETI: the Role of the Dedicated Amateur
terrestrial beings. Given that no human effort can impact this particular factor, : what can we do to maximize our chances SETI for SETI success? For a brief time (admittedly a mere eyeblink in human history), the govern- ments of planet Earth threw their prestige The Role of the and fiscal resources at the SETI problem, sponsoring any number of scientific searches. But it is amateurs who have made, and continue to make, the most sig- nificant strides toward contact. Dedicated Amateur An amateur, as defined by science and the Olympics Committee alike, is one Dr H. Paul Shuch, N6TX who strives to excel without financial compensation. The motivation of the ama- teur is revealed by the Latin root of the word: an amateur works for love. Ask any contemporary SETI scientist The Search for Extra-Terrestrial Intelligence or technologist why he or she strives against incredible odds. The answer is al- is moving forward on a number of fronts, ways the same. What modest salary he or she may draw is almost incidental. Any thanks in large part to amateurs who skilled SETIzen could always make more money by diverting the requisite effort in volunteer their time and expertise. a different direction. It is indeed for the love of the game that the best and the brightest choose to compete in the SETI Olympiad. ince its emergence as a respectable interpretation. Like the amateur scientific discipline nearly a half athlete competing in an Olympiad, the The Athletes century ago, the electromagnetic amateur SETIzen can expect to struggle Not all SETI pioneers are licensed ra- Search for Extra-Terrestrial Intelli- for survival, absent commercial or insti- dio amateurs (though those I will discuss Sgence (SETI) has been dominated by tutional sponsorship. -
Faint Gamma-Ray Bursts and Other High-Energy Transients Detected
Faint Gamma-Ray Bursts and Other High-Energy Transients Detected with BATSE by Jefferson Michael Kommers Submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physics at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY February 1999 © Massachusetts Institute of Technology 1999. All rights reserved. C Author........V .V ....... .. .. ...........- ... -- - ..... ...........----.- - Department of Physics December 15, 1998 d4 Certified byV Walter H. G. Lewin Professor of Physics Thesis Supervisor Accepted by ............... /Thomas, .Greytak Professor of Physics Associate Department Head for Education MCH SETTS INSTI TUTE LIBRARIES Faint Gamma-Ray Bursts and Other High-Energy Transients Detected with BATSE by Jefferson Michael Kommers Submitted to the Department of Physics on December 15, 1998, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physics ABSTRACT The Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma Ray Observatory detects gamma-ray bursts (GRBs) and other high-energy astronomi- cal transients using a real-time burst detection system running onboard the spacecraft. This thesis describes a search of the archival BATSE data for GRBs, emission from soft gamma-ray repeaters (SGRs), bursts and flares from X-ray binaries, and other transients that were not detected by the onboard system. The search covers six years of the mission, from 1992 December 9.0 to 1997 December 17.0. The search reveals 873 GRB candidates that did not activate the onboard burst detection because they were too faint, because they occurred while the onboard system was disabled for technical reasons, or because their time profile artificially raised the onboard detection threshold. -
PARKES OBSERVATORY, a Radio Telescope in a Tra Ia Ma E T E Fir T
PARKES OBSERVATORY, a radio telescope in Atraiamaetefrtetectionoamterio rieraioareromteitantniere. ScientiicAmerican A S T R O N O MY Flashes ın the Nıght Astronomers are racing to fgure out what causes powerful bursts of radio light in the distant cosmos By Duncan Lorimer and Maura McLaughlin ONE DAY IN EARLY 2007 UNDERGRADUATE STUDENT DAVID NARKEVIC came to us with some news. He was a physics major at West Virginia University, where the two of us had just begun our first year as assistant professors. We had tasked him with inspecting archival observations of the Magellanic Clouds—small satellite galaxies of the Milky Way about 200,000 light-years away from Earth. Narkevic had an understated manner, and that day was no exception. “I’ve found something that looks quite interesting,” he said nonchalantly, holding up a graph of a signal that was more than 100 times stronger than the background hiss of the telescope electronics. At first, it seemed that he had identified just what we were looking for: a very small, bright type of star known as a pulsar. IN BRIEF Getty Images Getty A strange burst of radio light from Astronomers doubted tht the sh A quest is on to discover more of Theories include compact stars, the distnt cosmos mstied scien- was celestial until they found similar these strange bursts and identify super novae and even exotic possibili- B. GOODMAN GOODMAN B. tists when they spotted it in 2007. blasts, dubbed “fast radio bursts.” what causes them. ties such as cosmic strings. ROBERT April 2018, ScientificAmerican.com 43 ScientiicAmerican These dense, magnetic stars shoot out light in beams that Duncan Lorimer is a professor of physics and astronomy sweep around as they rotate, making the star appear to “pulse” at West Virginia University’s Center for Gravitational Waves on and of like a lighthouse.