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Meerkat Commissioning & NRAO in South Africa
MeerKAT Commissioning & NRAO in South Africa Deb Shepherd NRAO & SKA Africa 10 Nov 2010 Radio telescopes around the World: Very Large Array (VLA), NM Very Long Baseline Array Green Bank Telescope (VLBA) , USA (GBT), WV Sub-Millimeter Array (SMA), Mauna Kea Owens Valley Radio Observatory (OVRO) + Berkeley-Illinois-Maryland Array (BIMA) = CARMA, CA http://www.ska.ac.za MeerKAT! QuickTime™ and a YUV420 codec decompressor are needed to see this picture. MeerKAT & the SKA 3000-4000 antennas MeerKAT: 64 - 13.5m Offset Gregorian antennas The MeerKAT Team MeerKAT Precursor Array MPA (or KAT-7) Today 2 1 3 4 5 Commissioning Accomplishments To Date • March 2010 - Regular commissioning activity began, tipping scans, pointing determination, gain curves. • April 2010 - First demonstration single dish image made (Centaurus A) • May 2010 - First demonstration interferometric image (4 antennas, warm receivers) • July 2010 - Holography system built and demonstrated on XDM and KAT antennas 5 & 6. • July 2010 - Noise diode calibration and Tsys determination for antennas 1-4 completed. Preliminary single dish commissioning evaluation complete for antennas 1-4 with warm receivers. • Aug/Sept 2010 - Commissioning paused; RFI measurement campaign • Nov 2010 - First cold feed installed on antenna 5 Tipping Curves • Antennas 1-4: tipping curve, warm receivers 1694-1960 MHz Tipping curve shape compares well with theoretical predictions, including spillover model provided by EMSS. AfriStar Pointing Determination • Antennas 1-4: pointing determination, warm receivers 1822 MHz center frequency All sky coverage 1.5’ RMS using all sources 0.76’ RMS using only 6 brightest sources Gain Curves • Antennas 1-4: Gain curve determination, warm receivers 1694-1950 MHz Preliminary gain, aperture efficiency, Tsys and SFED as a function of elevation. -
Astro2020 APC White Paper Panel on Radio
Astro2020 APC White Paper Panel on Radio, Millimeter, and Submillimeter Observations from the Ground The Case for a Fully Funded Green Bank Telescope Brief Description [350 character limit]: The NSF has reduced its funding for peer-reviewed use on the GBT to ~3900 hours/year, 60% of available science time. This greatly increases the telescope pressure & fragments the schedule, making it very difficult to allocate time for even the highest rated projects planned for the next decade. Here we seek funding for 1500 more hours annually. Principal Author: K. O’Neil (Green Bank Observatory; [email protected]) Co-authors: Felix J Lockman (Green Bank Observatory), Filippo D'Ammando (INAF-IRA Bologna), Will Armentrout (Green Bank Observatory), Shami Chatterjee (Cornell University), Jim Cordes (Cornell University), Martin Cordiner (NASA GSFC), David Frayer (Green Bank Observatory), Luke Zoltan Kelley (Northwestern University), Natalia Lewandowska (West Virginia University), Duncan Lorimer (WVU), Brian Mason (NRAO), Maura McLaughlin (West Virginia University), Tony Mroczkowski (European Southern Observatory), Hooshang Nayyeri (UC Irvine), Eric Perlman (Florida Institute of Technology), Bindu Rani (NASA Goddard Space Flight Center), Dominik Riechers (Cornell University), Martin Sahlan (Uppsala University), Ian Stephens (CfA/SAO), Patrick Taylor (Lunar and Planetary Institute), Francisco Villaescusa- Navarro (Center for Computational Astrophysics, Flatiron Institute) Endosers: Esteban D. Araya (Western Illinois University), Hector Arce (Yale -
Radio Astronomy & Radio Telescopes
Radio Astronomy & Radio Telescopes Tasso Tzioumis ([email protected]) Australia Telescope National Facility (ATNF) sms2020, Stellenbosch 2-6 March 2020 CSIRO ASTRONOMY AND SPACE SCIENCE Radio Astronomy – ITU definition 1.13 radio astronomy: Astronomy based on the reception of radio waves of cosmic origin. 1.5 radio waves or hertzian waves: Electromagnetic waves of frequencies arbitrarily lower than 3 000 GHz, propagated in space without artificial guide. • Astronomy covers the whole electromagnetic spectrum • Radio astronomy is the “low energy” part of the spectrum é 3 000 GHz Radioastronomy & Radio telescopes | Tasso Tzioumis Radio Astronomy “special” characteristics Technical challenges • Very faint signals – measured in 10-26 W/m2/Hz (-260 dBW) • “Power collected by all radiotelescopes since the start of radio astronomy would light a 1W bulb for less than 1 second” • à Need “sensitivity” i.e. large antennas and/or arrays of many antennas • à Very susceptible to intereference • Celestial structures at all scales: from very large to very small • à Need “spatial resolution” i.e. ability to see the details at all scales • à Need large antennas and/or arrays of many antennas • Astronomical events at all timescales(from < 1ms to > millions years) & and at all spectral resolutions (from < 1 Hz to GHz) • à Need very high time and frequency resolution • à Sensitive telescopes and arrays & extreme technical challenges Radioastronomy & Radio telescopes | Tasso Tzioumis Radio Astronomy “special” characteristics Scientific challenges • Radio -
Astronomische Waarneemtechnieken (Astronomical Observing Techniques) Based on Lectures by Bernhard Brandl Lecture 8: Radio 1
Astronomische Waarneemtechnieken (Astronomical Observing Techniques) Based on lectures by Bernhard Brandl Lecture 8: Radio 1. Introducon 2. Radio Emission 3. Observing 4. Antenna Technology 5. Receiver Technology 6. Back Ends 7. Calibraons (c) National Radio Astronomy Observatory / Associated Universities, Inc. / National Science Foundation The First Radio Astronomers http://en.wikipedia.org/wiki/Radio_telescope http://en.wikipedia.org/wiki/Radio_astronomy Grote Reber (1911-2002) Karl Guthe Jansky (1905-1950) Karl Jansky built (at Bell Telephone Laboratories) antenna to receive radio waves at 20.5 MHz (λ~14.6m) à “turntable” of 30m×6m à first detection of astronomical radio waves (à 1 Jy = 10−26 W m−2 Hz−1) Grote Reber extended Jansky's work, conducted first radio sky survey. For nearly a decade he was the world's only radio astronomer. Radio Astronomy Discoveries • radio (synchrotron) emission of the Milky Way (1933) • first discrete cosmic radio sources: supernova remnants and radio galaxies (1948) • 21-cm line of atomic hydrogen (1951) • Quasi Stellar Objects (1963) • Cosmic Microwave Background (1965) • Interstellar molecules ó Star formation (1968) • Pulsars (1968) Radio Observations through the Atmosphere • Radio window from ~10 MHz (30m) to 1 THz (0.3mm) • Low-frequency limit given by (reflecting) ionosphere • High frequency limit given by molecular transitions of atmospheric H2O and N2. Radio Wavelengths: PhotonsàElectric Fields • Directly measure electric fields of electro- magnetic waves • Electric fields excite currents in antennae • Currents can be amplified and split electrically. Radio Emission Mechanisms Most important astronomical radio emission mechanisms 1. Synchrotron emission 2. Free-free emission (thermal Bremsstrahlung) 3. Thermal (blackbody) emission (also from dust grains) 4. -
CORF Comments on RM11713 (00724414).DOC
Before the FEDERAL COMMUNICATIONS COMMISSION Washington, D.C. 20554 In the Matter of ) ) Battelle Memorial Institute, Inc. ) RM-11713 ) Petition for Rulemaking to Adopt Service Rules ) for the 102-109.5 GHz Band ) COMMENTS OF THE NATIONAL ACADEMY OF SCIENCES’ COMMITTEE ON RADIO FREQUENCIES The National Academy of Sciences, through the National Research Council's Committee on Radio Frequencies (hereinafter, CORF), hereby submits its comments in response to the Commission's February 24, 2014, Public Notice regarding the above- captioned Petition for Rulemaking.1 In these Comments, CORF discusses the potential impact on radio astronomy from the proposals in the Petition for Rulemaking (Petition) filed by Battelle Memorial Institute, Inc. (Battelle) that led to the initiation of this proceeding, as well as the ways to minimize that impact. CORF does not oppose fixed commercial use of the sort proposed in the Petition, as long as the Commission’s rules provide for appropriate frequency coordination sufficient to protect Radio Astronomy Service (RAS) observations.2 1 CORF hereby moves for leave to file these comments after the filing deadline. The public interest would be served by accepting the comments, since Battelle’s proposal would directly impact radio astronomy observatories, and no other parties in this proceeding have filed any information regarding that impact or the proposals to limit that impact. Thus, these comments will provide information important for the Commission’s consideration in this proceeding. Further, no parties will be harmed by the acceptance of these comments, as further rounds of comments are anticipated if the Commission grants the Battelle Petition and initiates a rulemaking proceeding. -
Z´AKLADY ASTRONOMIE a ASTROFYZIKY II Látka Prednášená
ZAKLADY´ ASTRONOMIE A ASTROFYZIKY II L´atka pˇredn´aˇsen´aM. Wolfem Na z´akladˇesv´ych pozn´amekz pˇredn´aˇskya dalˇs´ıliteratury sepsal M. B´ılek, korektury, doplˇnkyM. Zejda Verze 1: 6. z´aˇr´ı2010 Toto je zat´ımpracovn´ıverze skript. Je ne´upln´aa m˚uˇzeobsahovat menˇs´ıfaktick´echyby. V pˇr´ıpadˇe,ˇzenˇejakouobjev´ıte,nebo se v´ambude zd´atnˇejak´aˇc´asttextu nesrozumiteln´a, upozornˇetepros´ımautora nebo pˇredn´aˇsej´ıc´ıho.Doch´azkana pˇredn´aˇskuse doporuˇcuje. 2 Obsah 1 Atmosf´erick´aa vnˇeatmosf´erick´aastronomie 5 1.1 Uvod.......................................´ 5 1.2 Vliv atmosf´ery na astronomick´apozorov´an´ı. .5 1.2.1 Extinkce v atmosf´eˇre . .5 1.2.2 Seeing . .8 1.3 Bal´onov´aastronomie . .8 1.4 Druˇzicov´aastronomie . .9 2 Optick´aastronomie 13 2.1 Optick´edalekohledy . 13 2.1.1 Konstrukce dalekohled˚u . 13 2.1.2 Charakteristiky dalekohledu . 21 2.1.3 Optick´evady dalekohled˚u . 25 2.1.4 Okul´ary . 29 2.1.5 Filtry . 35 2.1.6 Mont´aˇze . 36 2.2 Optick´edetektory a jejich vyuˇzit´ıve fotometrii . 38 2.2.1 Nˇekter´eobecn´echarakteristiky fotometrick´ych detektor˚u. 39 2.2.2 Oko . 39 2.2.3 Fotografick´aemulze . 44 2.2.4 Foton´asobiˇce . 46 2.2.5 CCD . 48 2.3 Spektrografy . 53 2.3.1 Hranolov´yspektrograf . 55 2.3.2 Mˇr´ıˇzkov´yspektrograf . 55 3 R´adiov´aastronomie 63 4 Infraˇcerven´aastronomie 65 5 Rentgenov´aastronomie 67 6 Astronomie gama z´aˇren´ı 69 3 7 Astronomie gravitaˇcn´ıch vln 73 8 Neutrinov´aastronomie 75 9 Pˇr´ıstroje sluneˇcn´ıfyziky 79 10 Doporuˇcen´aliteratura 83 4 Kapitola 1 Atmosf´erick´aa vnˇeatmosf´erick´a astronomie 1.1 Uvod´ Pozorov´an´ıvesm´ırn´ych tˇelesz povrchu Zemˇe,na dnˇevzduˇsn´ehooce´anu, je pro astron- omy velmi omezuj´ıc´ı.Zemsk´aatmosf´era velmi dobˇrefiltruje z´aˇren´ıpˇrich´azej´ıc´ız vesm´ıru na povrch Zemˇe.V´ysledkem je, ˇzeˇzeZemˇem˚uˇzemevidˇetjen velmi omezen´erozsahy vl- nov´ych d´elekz´aˇren´ı,naz´yvan´a okna\. -
Astro2020 APC White Paper
Astro2020 APC White Paper Argus+: Wide-Field, High Resolution 3mm Molecular Imaging Type of Activity: Ground Based Project Space Based Project Infrastructure Activity Technological Development Activity State of the Profession Consideration Other Panel: Radio, Millimeter, and Submillimeter Observations from the Ground. Principal Author: Name: David T. Frayer Institution: Green Bank Observatory (GBO) Email: [email protected] Phone: 304-456-2223 Co-authors: Felix J. Lockman (GBO), Paul Goldsmith (JPL), Andrew I. Harris (Univ. of Maryland), Kieran A. Cleary (Caltech), Joshua O. Gundersen (Univ. of Miami), Laura Jensen (GBO), Alvaro Hacar (Leiden University), Che-Yu Chen (Univ. of Virginia), Will Armentrout (GBO), Natalie Butterfield (GBO), Larry Morgan (GBO), Amanda Kepley (NRAO), Jialu Li (Univ. of Maryland), Ian Stephens (CfA/SAO), Sarah Sadavoy (CfA/SAO), Kevin Harrington (Univ. of Bonn, AIfA), Jaime Pineda (Max-Planck), Zhi-Yun Li (Univ. of Virginia), Anthony Readhead (Caltech), Sarah Church (Stanford), Steven White (GBO), Randy McCullough (GBO), Galen Watts (GBO), Dennis Egan (GBO), Martin Bloss (GBO) Project Endorsers: Loren Anderson (West Virginia Univ.), Hector´ G. Arce (Yale Univ.), Tracy Becker (Southwest Research Institute), Robert Benjamin (U. Wisconsin-Whitewater), Alberto Bolatto (Univ. of Maryland), Amber Bonsall (GBO), Sara Cazzoli (Instituto de Astrofisica de Andalucia), Suchetana Chatterjee (Presidency University), Chian-Chou Chen (T.C.) (ESO), Claudia Cicone (INAF, University of Oslo), Martin Cordiner (NASA GSFC), Simon Dicker -
History of Radio Astronomy
History of Radio Astronomy Reading for High School Students Getsemary Báez Introduction form of radiation involved (soon known as electro- Radio Astronomy, a field that has strongly magnetic waves). Nevertheless, it was Oliver Heavi- evolved since the end of World War II, has become side who in conjunction with Willard Gibbs in 1884 one of the most important tools of astronomical ob- modified the equations and put them into modern servations. Radio astronomy has been responsible for vector notation. a great part of our understanding of the universe, its A few years later, Heinrich Hertz (1857- formation, composition, interactions, and even pre- 1894) demonstrated the existence of electromagnetic dictions about its future path. This article intends to waves by constructing a device that had the ability to inform the public about the history of radio astron- transmit and receive electromagnetic waves of about omy, its evolution, connection with solar studies, and 5m wavelength. This was actually the first radio the contribution the STEREO/WAVES instrument on wave transmitter, which is what we call today an LC the STEREO spacecraft will have on the study of oscillator. Just like Maxwell’s theory predicted, the this field. waves were polarized. The radiation emissions were detected using a 1mm thin circle of copper wire. Pre-history of Radio Waves Now that there is evidence of electromag- It is almost impossible to depict the most im- netic waves, the physicist Max Planck (1858-1947) portant facts in the history of radio astronomy with- was responsible for a breakthrough in physics that out presenting a sneak peak where everything later developed into the quantum theory, which sug- started, the development and understanding of the gests that energy had to be emitted or absorbed in electromagnetic spectrum. -
Radio Astronomy
Edition of 2013 HANDBOOK ON RADIO ASTRONOMY International Telecommunication Union Sales and Marketing Division Place des Nations *38650* CH-1211 Geneva 20 Switzerland Fax: +41 22 730 5194 Printed in Switzerland Tel.: +41 22 730 6141 Geneva, 2013 E-mail: [email protected] ISBN: 978-92-61-14481-4 Edition of 2013 Web: www.itu.int/publications Photo credit: ATCA David Smyth HANDBOOK ON RADIO ASTRONOMY Radiocommunication Bureau Handbook on Radio Astronomy Third Edition EDITION OF 2013 RADIOCOMMUNICATION BUREAU Cover photo: Six identical 22-m antennas make up CSIRO's Australia Telescope Compact Array, an earth-rotation synthesis telescope located at the Paul Wild Observatory. Credit: David Smyth. ITU 2013 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. - iii - Introduction to the third edition by the Chairman of ITU-R Working Party 7D (Radio Astronomy) It is an honour and privilege to present the third edition of the Handbook – Radio Astronomy, and I do so with great pleasure. The Handbook is not intended as a source book on radio astronomy, but is concerned principally with those aspects of radio astronomy that are relevant to frequency coordination, that is, the management of radio spectrum usage in order to minimize interference between radiocommunication services. Radio astronomy does not involve the transmission of radiowaves in the frequency bands allocated for its operation, and cannot cause harmful interference to other services. On the other hand, the received cosmic signals are usually extremely weak, and transmissions of other services can interfere with such signals. -
Essential Radio Astronomy
February 2, 2016 Time: 09:25am chapter1.tex © Copyright, Princeton University Press. No part of this book may be distributed, posted, or reproduced in any form by digital or mechanical means without prior written permission of the publisher. 1 Introduction 1.1 AN INTRODUCTION TO RADIO ASTRONOMY 1.1.1 What Is Radio Astronomy? Radio astronomy is the study of natural radio emission from celestial sources. The range of radio frequencies or wavelengths is loosely defined by atmospheric opacity and by quantum noise in coherent amplifiers. Together they place the boundary be- tween radio and far-infrared astronomy at frequency ν ∼ 1 THz (1 THz ≡ 1012 Hz) or wavelength λ = c/ν ∼ 0.3 mm, where c ≈ 3 × 1010 cm s−1 is the vacuum speed of light. The Earth’s ionosphere sets a low-frequency limit to ground-based radio astronomy by reflecting extraterrestrial radio waves with frequencies below ν ∼ 10 MHz (λ ∼ 30 m), and the ionized interstellar medium of our own Galaxy absorbs extragalactic radio signals below ν ∼ 2 MHz. The radio band is very broad logarithmically: it spans the five decades between 10 MHz and 1 THz at the low-frequency end of the electromagnetic spectrum. Nearly everything emits radio waves at some level, via a wide variety of emission mechanisms. Few astronomical radio sources are obscured because radio waves can penetrate interstellar dust clouds and Compton-thick layers of neutral gas. Because only optical and radio observations can be made from the ground, pioneering radio astronomers had the first opportunity to explore a “parallel universe” containing unexpected new objects such as radio galaxies, quasars, and pulsars, plus very cold sources such as interstellar molecular clouds and the cosmic microwave background radiation from the big bang itself. -
Structure in the Radio Counterpart to the 2004 Dec 27 Giant Flare From
SLAC-PUB-11623 astro-ph/0511214 Structure in the radio counterpart to the 2004 Dec 27 giant flare from SGR 1806-20 R. P. Fender1⋆, T.W.B. Muxlow2, M.A. Garrett3, C. Kouveliotou4, B.M. Gaensler5, S.T. Garrington2, Z. Paragi3, V. Tudose6,7, J.C.A. Miller-Jones6, R.E. Spencer2, R.A.M. Wijers6, G.B. Taylor8,9,10 1 School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ, UK 2 University of Manchester, Jodrell Bank Observatory, Cheshire, SK11 9DL, UK 3 Joint Institute for VLBI in Europe, Postbus 2, NL-7990 AA Dwingeloo, The Netherlands 4 NASA / Marshall Space Flight Center, NSSTC, XD-12, 320 Sparkman Drive, Huntsville, AL 35805, USA 5 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 6 Astronomical Institute ‘Anton Pannekoek’, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands 7 Astronomical Institute of the Romanian Academy, Cutitul de Argint 5, RO-040557 Bucharest, Romania 8 Kavli Institute of Particle Astrophysics and Cosmology, Menlo Park, CA 94025 USA 9 National Radio Astronomy Observatory, Socorro, NM 87801, USA 10Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, USA 8 November 2005 ABSTRACT On Dec 27, 2004, the magnetar SGR 1806-20 underwent an enormous outburst resulting in the formation of an expanding, moving, and fading radio source. We report observations of this radio source with the Multi-Element Radio-Linked Interferometer Network (MERLIN) and the Very Long Baseline Array (VLBA). The observations confirm the elongation and expansion already reported based on observations at lower angular resolutions, but suggest that at early epochs the structure is not consistent with the very simplest models such as a smooth flux distribution. -
REBER CIRCLE, GROTE REBER RADIO TELESCOPE SITE HAER No
REBER CIRCLE, GROTE REBER RADIO TELESCOPE SITE HAER No. HI-118 (Haleakala High Observatory Site) Pukalani Vicinity Maui County Hawaii PHOTOGRAPHS WRITTEN HISTORICAL AND DESCRIPTIVE DATA HISTORIC AMERICAN ENGINEERING RECORD U.S. Department of the Interior National Park Service San Francisco, California HISTORIC AMERICAN ENGINEERING RECORD REBER CIRCLE, GROTE REBER RADIO TELESCOPE SITE HAER No. HI-118 Location: Haleakala High Altitude Observatory Site (on Pu‘u Kolekole hill) Pukalani Vicinity Maui, Hawaii U.S.G.S. Topographic map, Kilohana Quadrangle 1991 (7.5 minute series) Universal Transverse Mercator Coordinates NAD 83: 04.785505. 2292557 Present Owner: University of Hawaii Institute for Astronomy Present Use: None Significance: Reber Circle is a significant resource in the history of the development of Haleakala for astronomical observation, as well as the development of Radio Astronomy generally. Reber’s telescope was the first to make use of Haleakala’s peak for the observation of celestial objects. It was also an important early radio telescope; guiding radio astronomers toward better placement of receiving antennas, with data gathered through it leading to Reber’s discoveries that modified ionospheric theory. Historian: Lesleigh Jones Mason Architects, Inc. 119 Merchant Street, Suite 501 Honolulu, HI 96813 Project Information: This report is part of a mitigation measure for the construction of the Advanced Technology Solar Telescope (ATST). This documentation was required under Section I.H. (2-7) of the Advanced Technology Solar Telescope Project Programmatic Agreement (PA), which was signed by the National Science Foundation, the National Park Service, the Advisory Council on Historic Preservation, the Hawaii State Historic Preservation Officer, The Association of Universities for Research In Astronomy, and the University of Hawai‘i (for the benefit of its Institute for Astronomy.