Square Kilometre Array Newsletter Volume 19 October 2010
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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 -
Optical SETI: the All-Sky Survey
Professor van der Veen Project Scientist, UCSB Department of Physics, Experimental Cosmology Group class 4 [email protected] frequencies/wavelengths that get through the atmosphere The Planetary Society http://www.planetary.org/blogs/jason-davis/2017/20171025-seti-anybody-out-there.html THE ATMOSPHERE'S EFFECT ON ELECTROMAGNETIC RADIATION Earth's atmosphere prevents large chunks of the electromagnetic spectrum from reaching the ground, providing a natural limit on where ground-based observatories can search for SETI signals. Searching for technology that we have, or are close to having: Continuous radio searches Pulsed radio searches Targeted radio searches All-sky surveys Optical: Continuous laser and near IR searches Pulsed laser searches a hypothetical laser beacon watch now: https://www.youtube.com/watch?time_continue=41&v=zuvyhxORhkI Theoretical physicist Freeman Dyson’s “First Law of SETI Investigations:” Every search for alien civilizations should be planned to give interesting results even when no aliens are discovered. Interview with Carl Sagan from 1978: Start at 6:16 https://www.youtube.com/watch?v=g- Q8aZoWqF0&feature=youtu.be Anomalous signal recorded by Big Ear Telescope at Ohio State University. Big Ear was a flat, aluminum dish three football fields wide, with reflectors at both ends. Signal was at 1,420 MHz, the hydrogen 21 cm ‘spin flip’ line. http://www.bigear.org/Wow30th/wow30th.htm May 15, 2015 A Russian observatory reports a strong signal from a Sun-like star. Possibly from advanced alien civilization. The RATAN-600 radio telescope in Zelenchukskaya, at the northern foot of the Caucasus Mountains location: star HD 164595 G-type star (like our Sun) 94.35 ly away, visually located in constellation Hercules 1 planet that orbits it every 40 days unusual radio signal detected – 11 GHz (2.7 cm) claim: Signal from a Type II Kardashev civilization Only one observation Not confirmed by other telescopes Russian Academy of Sciences later retracted the claim that it was an ETI signal, stating the signal came from a military satellite. -
Square Kilometre Array Computational Challenges
Square Kilometre Array Computational Challenges Paul Alexander Paul Alexander SKA Computational Challenges What is the Square Kilometre Array (SKA) • Next Generation radio telescope – compared to best current instruments it is ... E-MERLIN • ~100 times sensitivity • ~ 106 times faster imaging the sky • More than 5 square km of collecting area on sizes 3000km eVLA 27 27m dishes Longest baseline 30km GMRT 30 45m dishes Longest baseline 35 km Paul Alexander SKA Computational Challenges What is the Square Kilometre Array (SKA) • Next Generation radio telescope – compared to best current instruments it is ... • ~100 times sensitivity • ~ 106 times faster imaging the sky • More than 5 square km of collecting area on sizes 3000km • Will address some of the key problems of astrophysics and cosmology (and physics) • Builds on techniques developed in Cambridge • It is an interferometer • Uses innovative technologies... • Major ICT project • Need performance at low unit cost Paul Alexander SKA Computational Challenges Dishes Paul Alexander SKA Computational Challenges Phased Aperture array Paul Alexander SKA Computational Challenges also a Continental sized Radio Telescope • Need a radio-quiet site • Very low population density • Large amount of space • Possible sites (decision 2012) • Western Australia • Karoo Desert RSA Paul Alexander SKA Computational Challenges Sensitivity comparison 12,000 Sensitivity Comparison 10,000 1 - K 2 8,000 SKA2 6,000 SKA2 SKA1 MeerKAT LOFAR ASKAP 4,000 Sensitivity: Aeff/Tsys m Sensitivity:Aeff/Tsys eVLA SKA1 2,000 -
Detection Statistics of the Radioastron AGN Survey
Available online at www.sciencedirect.com ScienceDirect Advances in Space Research 65 (2020) 705–711 www.elsevier.com/locate/asr Detection statistics of the RadioAstron AGN survey Y.Y. Kovalev a,b,c,⇑, N.S. Kardashev a,†, K.V. Sokolovsky a,d,e, P.A. Voitsik a,T.Anf, J.M. Anderson g,h, A.S. Andrianov a, V.Yu. Avdeev a, N. Bartel i, H.E. Bignall j, M.S. Burgin a, P.G. Edwards k, S.P. Ellingsen l, S. Frey m, C. Garcı´a-Miro´ n, M.P. Gawron´ski o, F.D. Ghigo p, T. Ghosh p,q, G. Giovannini r,s, I.A. Girin a, M. Giroletti r, L.I. Gurvits t,u, D.L. Jauncey k,v, S. Horiuchi w, D.V. Ivanov x, M.A. Kharinov x, J.Y. Koay y, V.I. Kostenko a, A.V. Kovalenko aa, Yu.A. Kovalev a, E.V. Kravchenko r,a, M. Kunert-Bajraszewska o, A.M. Kutkin a,z, S.F. Likhachev a, M.M. Lisakov c,a, I.D. Litovchenko a, J.N. McCallum l, A. Melis ab, A.E. Melnikov x, C. Migoni ab, D.G. Nair t, I.N. Pashchenko a, C.J. Phillips k, A. Polatidis z, A.B. Pushkarev a,ad, J.F.H. Quick ae, I.A. Rakhimov x, C. Reynolds j, J.R. Rizzo af, A.G. Rudnitskiy a, T. Savolainen ag,ah,c, N.N. Shakhvorostova a, M.V. Shatskaya a, Z.-Q. Shen f,ac, M.A. Shchurov a, R.C. Vermeulen z, P. de Vicente ai, P. -
(LWA): a Large HF/VHF Array for Solar Physics, Ionospheric Science, and Solar Radar
The Long Wavelength Array (LWA): A Large HF/VHF Array for Solar Physics, Ionospheric Science, and Solar Radar A Ground-Based Instrument Paper for the 2010 NRC Decadal Survey of Solar and Space Physics Lee J Rickard, Joseph Craig, Gregory B. Taylor, Steven Tremblay, and Christopher Watts University of New Mexico, Albuquerque, NM 87131 Namir E. Kassim, Tracy Clarke, Clayton Coker, Kenneth Dymond, Joseph Helmboldt, Brian C. Hicks, Paul Ray, and Kenneth P. Stewart Naval Research Laboratory, Washington, DC 20375 Jacob M. Hartman NRC Research Associate, in residence at Naval Research Laboratory Stephen M. White AFRL, Kirtland AFB, Albuquerque, NM 87117 Paul Rodriguez Consultant, Washington, DC 20375 Steve Ellingson and Chris Wolfe Virginia Tech, Blacksburg, VA 24060 Robert Navarro and Joseph Lazio NASA Jet Propulsion Laboratory, Pasadena, CA 91109 Charles Cormier and Van Romero New Mexico Institute of Mining & Technology, Socorro, NM 87801 Fredrick Jenet University of Texas, Brownsville, TX 78520 and the LWA Consortium Executive Summary The Long Wavelength Array (LWA), currently under construction in New Mexico, will be an imaging HF/VHF interferometer providing a new approach for studying the Sun-Earth environment from the surface of the sun through the Earth’s ionosphere [1]. The LWA will be a powerful tool for solar physics and space weather investigations, through its ability to characterize a diverse range of low- frequency, solar-related emissions, thereby increasing our understanding of particle acceleration and shocks in the solar atmosphere along with their impact on the Sun-Earth environment. As a passive receiver the LWA will directly detect Coronal Mass Ejections (CMEs) in emission, and indirectly through the scattering of cosmic background sources. -
RESEARCH FACILITIES for the SCIENTIFIC COMMUNITY
NATIONAL RADIO ASTRONOMY OBSERVATORY RESEARCH FACILITIES for the SCIENTIFIC COMMUNITY 2020 Atacama Large Millimeter/submillimeter Array Karl G. Jansky Very Large Array Central Development Laboratory Very Long Baseline Array CONTENTS RESEARCH FACILITIES 2020 NRAO Overview.......................................1 Atacama Large Millimeter/submillimeter Array (ALMA).......2 Very Long Baseline Array (VLBA) .........................6 Karl G. Jansky Very Large Array (VLA)......................8 Central Development Laboratory (CDL)..................14 Student & Visitor Programs ..............................16 (above image) One of the five ngVLA Key Science Goals is Using Pulsars in the Galactic Center to Make a Fundamental Test of Gravity. Pulsars in the Galactic Center represent clocks moving in the space-time potential of a super-massive black hole and would enable qualitatively new tests of theories of gravity. More generally, they offer the opportunity to constrain the history of star formation, stellar dynamics, stellar evolution, and the magneto-ionic medium in the Galactic Center. The ngVLA combination of sensitivity and frequency range will enable it to probe much deeper into the likely Galactic Center pulsar population to address fundamental questions in relativity and stellar evolution. Credit: NRAO/AUI/NSF, S. Dagnello (cover) ALMA antennas. Credit: NRAO/AUI/NSF; ALMA, P. Carrillo (back cover) ALMA map of Jupiter showing the distribution of ammonia gas below Jupiter’s cloud deck. Credit: ALMA (ESO/NAOJ/NRAO), I. de Pater et al.; NRAO/AUI NSF, S. Dagnello NRAO Overview ALMA photo courtesy of D. Kordan ALMA photo courtesy of D. The National Radio Astronomy Observatory (NRAO) is delivering transformational scientific capabili- ties and operating three world-class telescopes that are enabling the as- tronomy community to address its highest priority science objectives. -
Fact Sheet Fact Sheet
FactFact sheet sheet What is the SKA? The Square Kilometre Array (SKA) is a next-generation radio telescope that will be vastly more sensitive than the best present-day instruments. It will give astronomers remarkable insights into the formation of the early Universe, including the emergence of the first stars, galaxies and other structures. This will shed light on the birth, and eventual death, of the cosmos. The SKA will require new technology and progress in Why build the SKA? fundamental engineering in fields such as information and communication technology, high performance computing In order to answer some fundamental questions about the and production manufacturing techniques. It will comprise origin and evolution of the Universe, a more sensitive radio a vast array of antennas, arranged in clusters to be spread telescope is needed that can detect the very weak signals over 3000 kilometres or more. The antennas will be linked coming from the edge of the cosmos. A telescope such as the electronically to form one enormous telescope. The SKA will be able to “see” distant objects in the very young combination of unprecedented collecting area, versatility Universe and provide answers to questions such as the and sensitivity will make the SKA the world’s premier imaging emergence of the first stars, galaxies and other structures. and survey telescope over a wide range of radio frequencies, Because the speed of light is finite and the size of the Universe producing the sharpest pictures of the sky of any telescope. is so large, telescopes are effectively time machines, enabling astronomers to look into the past and study the Universe as it The SKA will: was billions of years ago. -
High-Resolution Radio Observations of Submillimetre Galaxies
Mon. Not. R. Astron. Soc. 000, 000–000 (0000) Printed 7 November 2018 (MN LATEX style file v2.2) High-resolution radio observations of submillimetre galaxies A. D. Biggs1⋆ and R.J. Ivison1,2 1UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ 2Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ Accepted 2007 December 17. Received 2007 December 14; in original form 2007 September 11 ABSTRACT We have produced sensitive, high-resolution radio maps of 12 submillimetre (submm) galax- ies (SMGs) in the Lockman Hole using combined Multi-Element Radio-Linked Interferom- eter Network (MERLIN) and Very Large Array (VLA) data at a frequency of 1.4GHz. Inte- grating for 350hr yielded an r.m.s. noise of 6.0 µJybeam−1 and a resolution of 0.2–0.5arcsec. For the first time, wide-field data from the two arrays have been combined in the (u, v) plane and the bandwidthsmearing response of the VLA data has been removed.All of the SMGs are detected in our maps as well as sources comprising a non-submm luminous control sample. We find evidence that SMGs are more extended than the general µJy radio population and that therefore, unlike in local ultraluminous infrared galaxies (ULIRGs), the starburst compo- nent of the radio emission is extended and not confined to the galactic nucleus. For the eight sources with redshifts we measure linear sizes between 1 and 8kpc with a median of 5kpc. Therefore, they are in general larger than local ULIRGs which may support an early-stage merger scenario for the starburst trigger. -
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. -
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. -
The Mid-Frequency Square Kilometre Array Phase Synchronisation System
Publications of the Astronomical Society of Australia (PASA) doi: 10.1017/pas.2018.xxx. The Mid-Frequency Square Kilometre Array Phase Synchronisation System S. W. Schediwy1,2,∗, D. R. Gozzard1,2, C. Gravestock1, S. Stobie1, R. Whitaker3, J. A. Malan4, P. Boven5 and K. Grainge3 1International Centre for Radio Astronomy Research, School of Physics, Mathematics & Computing, The University of Western Australia, Perth, WA 6009, Australia 2Department of Physics, School of Physics, Mathematics & Computing, The University of Western Australia, Perth, WA 6009, Australia 3Jodrell Bank Centre for Astrophysics, School of Physics & Astronomy, The University of Manchester, Manchester, M13 9PL, UK 4Square Kilometre Array South Africa, The South African Radio Astronomy Observatory, Pinelands 7405, South Africa 5Joint Institute for VLBI ERIC (JIVE), Dwingeloo, The Netherlands Abstract This paper describes the technical details and practical implementation of the phase synchronisation system selected for use by the Mid-Frequency Square Kilometre Array (SKA). Over a four-year period, the system has been tested on metropolitan fibre-optic networks, on long-haul overhead fibre at the South African SKA site, and on existing telescopes in Australia to verify its functional performance. The tests have shown that the system exceeds the 1-second SKA coherence loss requirement by a factor of 2560, the 60-second coherence loss requirement by a factor of 239, and the 10-minute phase drift requirement by almost five orders-of-magnitude. The paper also reports on tests showing that the system can operate within specification over all the required operating conditions, including maximum fibre link distance, temperature range, temperature gradient, relative humidity, wind speed, seismic resilience, electromagnetic compliance, frequency offset, and other operational requirements. -
Wikipedia, the Free Encyclopedia
SKA newsletter Volume 21 - April 2011 The Square Kilometre Array Exploring the Universe with the world’s largest radio telescope www.skatelescope.org Please click the relevant section title to skip to that section 03 Project news 04 From the SPDO 05 SKA science 08 Engineering update 10 Site characterisation 12 Outreach update 14 Industry participation 17 News from around the world 18 Africa 20 Australia and New Zealand 23 Canada 25 China 28 Europe 31 India 33 US 35 Future meetings and events Project news Project news 04 From the SPDO Crucial steps for the SKA project were At its first meeting on 2 April, the Founding taken in the last week of March 2011. A Board decided that the location of the SKA Founding Board was created with the Project Office (SPO) will be at the Jodrell aim of establishing a legal entity for the Bank Observatory near Manchester in the project by the time of the SKA Forum in UK. This decision followed a competitive Canada in early July, as well as agreeing bidding process in which a number of the resourcing of the Project Execution excellent proposals were evaluated in an Plan for the Pre-construction Phase international review process. The SPO, which from 2012 to 2015. The Founding Board is hoped to grow to 60 people over the next replaces the Agencies SKA Group with four years, will supersede the SPDO currently immediate effect. Prof John Womersley based at the University of Manchester. The from the UK’s Science and Technology physical move to a new building at Jodrell Facilities Council (STFC) was elected Bank Observatory is scheduled for mid-2012.