Commission B4 Triennial Report (2018-2021)
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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. -
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. -
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. -
16Th HEAD Meeting Session Table of Contents
16th HEAD Meeting Sun Valley, Idaho – August, 2017 Meeting Abstracts Session Table of Contents 99 – Public Talk - Revealing the Hidden, High Energy Sun, 204 – Mid-Career Prize Talk - X-ray Winds from Black Rachel Osten Holes, Jon Miller 100 – Solar/Stellar Compact I 205 – ISM & Galaxies 101 – AGN in Dwarf Galaxies 206 – First Results from NICER: X-ray Astrophysics from 102 – High-Energy and Multiwavelength Polarimetry: the International Space Station Current Status and New Frontiers 300 – Black Holes Across the Mass Spectrum 103 – Missions & Instruments Poster Session 301 – The Future of Spectral-Timing of Compact Objects 104 – First Results from NICER: X-ray Astrophysics from 302 – Synergies with the Millihertz Gravitational Wave the International Space Station Poster Session Universe 105 – Galaxy Clusters and Cosmology Poster Session 303 – Dissertation Prize Talk - Stellar Death by Black 106 – AGN Poster Session Hole: How Tidal Disruption Events Unveil the High 107 – ISM & Galaxies Poster Session Energy Universe, Eric Coughlin 108 – Stellar Compact Poster Session 304 – Missions & Instruments 109 – Black Holes, Neutron Stars and ULX Sources Poster 305 – SNR/GRB/Gravitational Waves Session 306 – Cosmic Ray Feedback: From Supernova Remnants 110 – Supernovae and Particle Acceleration Poster Session to Galaxy Clusters 111 – Electromagnetic & Gravitational Transients Poster 307 – Diagnosing Astrophysics of Collisional Plasmas - A Session Joint HEAD/LAD Session 112 – Physics of Hot Plasmas Poster Session 400 – Solar/Stellar Compact II 113 -
THOMAS M. CRAWFORD University of Chicago
Department of Astronomy and Astrophysics ERC 433 5640 South Ellis Avenue Chicago, IL 60637 Office: 773.702.1564, Home: 773.580.7491 THOMAS M. CRAWFORD [email protected] University of Chicago DEGREES PhD University of Chicago. Astronomy & Astrophysics. 2003. MS University of Chicago. Astronomy & Astrophysics. 1997. BS DePaul University. Physics. 1996. BA Columbia University. German Language & Literature. 1992. DISSERTATION Title: Mapping the Southern Polar Cap with a Balloon-borne Millimeter-wave Telescope. Advisor: Stephan Meyer. HONORS Breakthrough Prize Winner. 2020. National Academy of Sciences Kavli Fellow. 2014. NASA Center of Excellence Award. 2002. NASA Graduate Student Research Fellowship. 1999–2002. B.S. conferred With Highest Honors. B.A. conferred Magna Cum Laude. ACADEMIC POSITIONS University of Chicago: Research Professor, Department of Astronomy & Astrophysics. 2019–Present. University of Chicago: Senior Researcher, Kavli Institute for Cosmological Physics. 2009–Present. University of Chicago: Research Associate Professor, Department of Astronomy & Astrophysics. 2017–2019. University of Chicago: Senior Research Associate, Department of Astronomy & Astrophysics. 2009–2017. University of Chicago: Research Scientist, Department of Astronomy & Astrophysics. 2006–2009. University of Chicago: Associate Fellow, Kavli Institute for Cosmological Physics. 2003–2009. University of Chicago: Research Associate, Department of Astronomy & Astrophysics. 2003–2006. Thomas M. Crawford, page 2 of 11 RECENT SYNERGISTIC ACTIVITIES Chair, Simons Observatory operations review committee, October 2020 Member, CMB-S4 Collaboration Governing Board, 2018 – present Member, NASA Legacy Archive for Microwave Background Data Analysis (LAMBDA) Users’ Group, 2016 – present Referee, Physical Review D, Physical Review Letters, Astrophysical Journal, Nature, Journal of Cosmology and Astroparticle Physics, and others, 2008 – present DOE, NASA, and NSF review panel member, 2013 – present RECENT INVITED COLLOQUIA AND SEMINARS University of Chicago: Astronomy Colloquium. -
The Effect of the Ionosphere on Ultra-Low-Frequency Radio-Interferometric Observations? F
A&A 615, A179 (2018) Astronomy https://doi.org/10.1051/0004-6361/201833012 & © ESO 2018 Astrophysics The effect of the ionosphere on ultra-low-frequency radio-interferometric observations? F. de Gasperin1,2, M. Mevius3, D. A. Rafferty2, H. T. Intema1, and R. A. Fallows3 1 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands e-mail: [email protected] 2 Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany 3 ASTRON – the Netherlands Institute for Radio Astronomy, PO Box 2, 7990 AA Dwingeloo, The Netherlands Received 13 March 2018 / Accepted 19 April 2018 ABSTRACT Context. The ionosphere is the main driver of a series of systematic effects that limit our ability to explore the low-frequency (<1 GHz) sky with radio interferometers. Its effects become increasingly important towards lower frequencies and are particularly hard to calibrate in the low signal-to-noise ratio (S/N) regime in which low-frequency telescopes operate. Aims. In this paper we characterise and quantify the effect of ionospheric-induced systematic errors on astronomical interferometric radio observations at ultra-low frequencies (<100 MHz). We also provide guidelines for observations and data reduction at these frequencies with the LOw Frequency ARray (LOFAR) and future instruments such as the Square Kilometre Array (SKA). Methods. We derive the expected systematic error induced by the ionosphere. We compare our predictions with data from the Low Band Antenna (LBA) system of LOFAR. Results. We show that we can isolate the ionospheric effect in LOFAR LBA data and that our results are compatible with satellite measurements, providing an independent way to measure the ionospheric total electron content (TEC). -
Large Ground-Based Projects Astronomy & Astrophysics Advisory
Large Ground-based Projects Astronomy & Astrophysics Advisory Committee Ralph Gaume, Joe Pesce, Nigel Sharp (AST) Jim Whitmore (PHY) February 25, 2019 16 Projects to be discussed o US-ELT: Ralph Gaume o Federal participation in US-based ELT projects to provide broad community access o ngVLA: Joe Pesce o Next generation radio array expanding across the American sub- continent o IceCube-Gen2: Jim Whitmore o Expand the cubic kilometer neutrino detector ten-fold in volume o CMB-S4: Nigel Sharp o Coordinated Stage 4 CMB experiment across Atacama high site and South Pole facility 17 The Aspiration US-ELT Bi-hemispheric ELT system 2 telescopes, 2 hemispheres, 1 system All-sky coverage Broad instrument suite Key Science Programs Open Access ≥ 25% at both facilities Strengthen U.S. scientific leadership Opportunity to significantly broaden U.S. public access to the next generation of optical- infrared telescopes 18 KSP development • 6 July: NOAO issued call for community participation in KSP development • 250+ participants responded • 66% unaffiliated with GMT/TMT partners • 8 Topical Groups, each with 2 conveners • TMT/GMT projects and instrument teams providing information & support • Telescope/instrumentation descriptions • On-line tools (e.g., some ETCs) • 86 participants at November KSP development workshop (Tucson) ~80% of public time for KSPs ~20% for PI-class, allocated annually 19 The Power Of Two Greater Science, More Access All-sky access • Relatively rare objects (e.g., GW sources, nearby exoplanets) • Unique targets in each hemisphere -
The Giant Flares of the Microquasar Cygnus X-3: X-Raysstates and Jets
galaxies Article The Giant Flares of the Microquasar Cygnus X-3: X-RaysStates and Jets Sergei Trushkin 1,2,*,† ID , Michael McCollough 3,†, Nikolaj Nizhelskij 1,† and Peter Tsybulev 1,† 1 The Special Astrophysical Observatory of the Russian Academy of Sciences, Niznij Arkhyz 369167, Russia; [email protected] (N.N.); [email protected] (P.T.) 2 Institute of Physics, Kazan Federal University, Kazan 420008, Russia 3 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA; [email protected] * Correspondence: [email protected] or [email protected]; Tel.: +7-928-396-3178 † These authors contributed equally to this work. Received: 18 September 2017; Accepted: 21 November 2017; Published: 27 November 2017 Abstract: We report on two giant radio flares of the X-ray binary microquasar Cyg X-3, consisting of a Wolf–Rayet star and probably a black hole. The first flare occurred on 13 September 2016, 2000 days after a previous giant flare in February 2011, as the RATAN-600 radio telescope daily monitoring showed. After 200 days on 1 April 2017, we detected a second giant flare. Both flares are characterized by the increase of the fluxes by almost 2000-times (from 5–10 to 17,000 mJy at 4–11 GHz) during 2–7 days, indicating relativistic bulk motions from the central region of the accretion disk around a black hole. The flaring light curves and spectral evolution of the synchrotron radiation indicate the formation of two relativistic collimated jets from the binaries. Both flares occurred when the source went from hypersoft X-ray states to soft ones, i.e. -
Memorial Text for HM018
A MEMORIAL RECOGNIZING THE NATIONAL RADIO ASTRONOMY OBSERVATORY'S VERY LARGE ARRAY RADIO TELESCOPE FOR ITS PROMINENCE IN THE FIELD OF ASTRONOMY AND FOR ITS CONTRIBUTIONS TOWARD THE ADVANCEMENT OF SCIENTIFIC KNOWLEDGE. WHEREAS, the very large array radio telescope, situated outside of Socorro, New Mexico, is one of the world's premier astronomical radio observatories; and WHEREAS, the very large array radio telescope is an exceedingly powerful scientific instrument, which has transformed many areas of astronomy in its years of operation; and WHEREAS, the array operations center is located on the campus of the New Mexico institute of mining and technology, which also provides scientific, engineering, technical, computer and support staff for the very large array radio telescope as well as the very long baseline array radio telescope; and WHEREAS, the very large array radio telescope has a long history in New Mexico, having been approved by congress in 1972, constructed between 1973 and 1980 and dedicated in 1980; and WHEREAS, the very large array radio telescope in New Mexico is still the most productive astronomical instrument on HM 18 Page 1 earth; and WHEREAS, it consists of twenty-seven radio antennas, each of which is eighty-two feet in diameter, placed in a Y- shaped configuration; and WHEREAS, data from the twenty-seven antennas are combined electronically to give the resolution of an antenna twenty-two miles across, with the sensitivity of a dish four hundred twenty-two feet in diameter; and WHEREAS, Socorro, New Mexico, was chosen -
Anchored in Shadows: Tying the Celestial Reference Frame Directly to Black Hole Event Horizons
URSI GASS 2020, Rome, Italy, 29 August - 5 September 2020 Anchored in Shadows: Tying the Celestial Reference Frame Directly to Black Hole Event Horizons T. M. Eubanks Space Initiatives Inc Palm Bay, Florida, USA [email protected] Abstract the micro arc second level, and showing that natural radio sources can exhibit brightness temperatures > 1013 K[5]. Both the radio International Celestial Reference Frame This work clearly needs to be continued and extended with (ICRF) and the optical Gaia Celestial Reference Frame larger space radio telescopes at even higher frequencies. (Gaia-CRF2) are derived from observations of jets pro- Further impetus to a new space VLBI mission has been re- duced by the Super Massive Black Holes (SMBH) power- cently provided by the successful imaging of the shadow of ing active galactic nuclei and quasars. These jets are inher- M87 by Event Horizon Telescope (EHT) [6]. ently subject to change and will appear different at differ- ent observing frequencies, leading to instabilities and sys- The EHT is pushing the limits of what is possible with tematic errors in the resulting Celestial Reference Frames purely terrestrial VLBI, due to the limitations caused at- (CRFs). Recently, the Event Horizon Telescope (EHT), a mospheric absorption in the mm and sub-mm bands, which mm-wave Very Long Baseline Interferometry (VLBI) array, limits both the frequencies used and which limits the EHT has observed the 40 μas diameter shadow of the SMBH in to using mostly very dry and high-altitude sites, limiting M87 at 1.3 mm, showing that the emitting region is smaller the (u,v) plane imaging coverage.