EDGES Memo #054

Total Page：16

File Type：pdf, Size：1020Kb

EDGES MEMO #054 MASSACHUSETTS INSTITUTE OF TECHNOLOGY HAYSTACK OBSERVATORY WESTFORD, MASSACHUSETTS 01886 December 1, 2009 Telephone: 781-981-5407 Fax: 781-981-0590 To: EDGES Group From: Alan E.E. Rogers Subject: Meteor scatter rates Since all the World’s designated radio quiet zones are les than 2000 km from strong radio transmitters they are subject to RFI from meteor scatter. The key parameters of meteor scatter are poorly determined. For example, theory suggests that the radar cross-section (RCS) should decrease by 20 dB per decade from head echoes but measurements typically have an even faster decline with frequency. The frequency range for significant scatter and the range of concern to radio astronomy is about 50 to 300 MHz. Some papers claim that 1012 meteors enter the Earth’s atmosphere each day while others suggest a number more like 109. In practice we observed a rate of about 1 per minute when located in a canyon (see memo #52) with sky coverage limited to elevations greater than about 25 degrees. Based on the geometry of Figure 1 this corresponds to a worldwide rate of about 107/day. Figure 2 shows the estimated burst rate as a function of elevation cut-off angle. This very sharp curve shows the advantage of limiting the low elevation response of the antenna or using the terrain to limit the elevation angle. Potential locations for EDGES are on route 205 in the canyon just before 205 enters the Catlow Valley, Oregon or about 1km West of route 205 on Skull creek road. 1 h R To solve: theta=acos( ( (R+ h)*(R+ h)+ R*R-r*r) / (2*(R+ h)*R)) a 1 b -2*R*cos(elev+90) c = -(R+h)*(R+h)+R*R r = ((- b+sqrt(b*b-4*a*c) / (2*a) ; R earth radius = 6357 km r = region where meteors form ions ,-..J 100 km Figure 1. Geometry of meteor seat ter 2 1 .......... -1 C) (I) 10 --....__f/l ...,f/l ~ -2 ~ 10 ..__,(I) ...,(I) ro -3 ...,i-.. 10 f/l i-.. ::l .n -4 i-.. 0 10 ...,(I) (I) s -5 10 -6 10 0 10 20 30 40 50 60 70 80 90 Elevation limit (deg) Figu r e 2. Rate of meteor scatter events vs elevation limit 3.

Copy Link

Recommended publications

The Global Jet Structure of the Archetypical Quasar 3C 273
galaxies Article The Global Jet Structure of the Archetypical Quasar 3C 273 Kazunori Akiyama 1,2,3,*, Keiichi Asada 4, Vincent L. Fish 2 ID , Masanori Nakamura 4, Kazuhiro Hada 3 ID , Hiroshi Nagai 3 and Colin J. Lonsdale 2 1 National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA 2 Massachusetts Institute of Technology, Haystack Observatory, 99 Millstone Rd, Westford, MA 01886, USA; vfi[email protected] (V.L.F.); [email protected] (C.J.L.) 3 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; [email protected] (K.H.); [email protected] (H.N.) 4 Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan; [email protected] (K.A.); [email protected] (M.N.) * Correspondence: [email protected] Received: 16 September 2017; Accepted: 8 January 2018; Published: 24 January 2018 Abstract: A key question in the formation of the relativistic jets in active galactic nuclei (AGNs) is the collimation process of their energetic plasma flow launched from the central supermassive black hole (SMBH). Recent observations of nearby low-luminosity radio galaxies exhibit a clear picture of parabolic collimation inside the Bondi accretion radius. On the other hand, little is known of the observational properties of jet collimation in more luminous quasars, where the accretion flow may be significantly different due to much higher accretion rates. In this paper, we present preliminary results of multi-frequency observations of the archetypal quasar 3C 273 with the Very Long Baseline Array (VLBA) at 1.4, 15, and 43 GHz, and Multi-Element Radio Linked Interferometer Network (MERLIN) at 1.6 GHz.
[Show full text]
CASKAR: a CASPER Concept for the SKA Phase 1 Signal Processing Sub-System
CASKAR: A CASPER concept for the SKA phase 1 Signal Processing Sub-system Francois Kapp, SKA SA Outline • Background • Technical – Architecture – Power • Cost • Schedule • Challenges/Risks • Conclusions Background CASPER Technology MeerKAT Who is CASPER? • Berkeley Wireless Research Center • Nancay Observatory • UC Berkeley Radio Astronomy Lab • Oxford University Astrophysics • UC Berkeley Space Sciences Lab • Metsähovi Radio Observatory, Helsinki University of • Karoo Array Telescope / SKA - SA Technology • NRAO - Green Bank • New Jersey Institute of Technology • NRAO - Socorro • West Virginia University Department of Physics • Allen Telescope Array • University of Iowa Department of Astronomy and • MIT Haystack Observatory Physics • Harvard-Smithsonian Center for Astrophysics • Ohio State University Electroscience Lab • Caltech • Hong Kong University Department of Electrical and Electronic Engineering • Cornell University • Hartebeesthoek Radio Astronomy Observatory • NAIC - Arecibo Observatory • INAF - Istituto di Radioastronomia, Northern Cross • UC Berkeley - Leuschner Observatory Radiotelescope • Giant Metrewave Radio Telescope • University of Manchester, Jodrell Bank Centre for • Institute of Astronomy and Astrophysics, Academia Sinica Astrophysics • National Astronomical Observatories, Chinese Academy of • Submillimeter Array Sciences • NRAO - Tucson / University of Arizona Department of • CSIRO - Australia Telescope National Facility Astronomy • Parkes Observatory • Center for Astrophysics and Supercomputing, Swinburne University
[Show full text]
Next Generation Radio Arrays
NextNext GenerationGeneration RadioRadio ArraysArrays Dr.Dr. FrankFrank D.D. LindLind MITMIT HaystackHaystack ObservatoryObservatory (with acknowledgement to my colleagues who contribute to these efforts...) [McKay-Bukowski, et al., 2014] contact info : Frank D. Lind MIT Haystack Observatory Route 40 Westford MA, 01886 email - [email protected] DeepDeep MemoryMemory Solid state memory capacity will exceed our data storage requirements. Deep memory instruments will become possible. Store all data from every element for the life of a radio array... Intel + Micron 3D Flash Intel XPoint memory Keon Jae Lee of the Korea Advanced Institute of Science and Technology (KAIST) ConnectedConnected WorldWorld Wireless networks will be global and even replace the wires. Disconnected, self networking, and software realized instrumentation Sparse global radio arrays, deployable dense arrays, and ad-hoc arrays DisappearingDisappearing SensorsSensors Integration will become extreme and include quantum referenced sensors Receivers in connectors, cloud computers on a chip, really good clocks Energy harvesting and low power near field wireless data Self coherent arrays, personal passive radar, the ionosphere as a sensor Deployable Low Power Radio Platforms Instruments in ~ 10W power envelopes. Future systems will use ~ 1W of power total. Zero infrastructure radio science instrumentation Software radio and radar technology Solar and battery power Low power computing for data acquisition Intelligent control software Mahali Array (during build out) Deep
[Show full text]
Real-Time High Volume Data Transfer and Processing for E-VLBI
Real-time high volume data transfer and processing for e-VLBI Yasuhiro Koyama, Tetsuro Kondo, Hiroshi Takeuchi, Moritaka Kimura (Kashima Space Research Center, NICT, Japan) and Masaki Hirabaru (New Generation Network Research Center, NICT, Japan) OutlineOutline What is e-VLBI? Why e-VLBI is necessary? How? – K5 VLBI System ~ Standardization – Network Test Experiments – June 2004 : Near-Realtime UT1 Estimation – January 2005 : Realtime Processing Demo Future Plan Traditional VLBI The Very-Long Baseline Interferometry (VLBI) Technique (with traditional data recording) The Global VLBI Array (up to ~20 stations can be used simultaneously) WhatWhat isis ee--VVLBI?LBI? VLBI=Very Long Baseline Interferometry Correlator Radio Telescope Network Correlator Radio Telescope Shipping Data Media e-VLBI (Tapes/Disks) Conventional VLBI VLBIVLBI ApplicationsApplications Geophysics and Plate Tectonics Kashima-Kauai鹿島－ハワイの基線長変化 Baseline Length -63.5 ± 0.5 mm/year 400 200 0 -200 基線長（ｍｍ） -400 5400km 5400km Fairbanksアラスカ 1984 1986 1988 1990 1992 1994 Fairbanks-Kauaiアラスカ－ハワイの基線長変化年 Baseline Length 4700km 4700km -46.1 ± 0.3 mm/year Kashima鹿島 400 5700km 200 Kauaiハワイ 0 -200 基線長（ｍｍ） -400 1984 1986 1988 1990 1992 1994 Kashima-Fairbanks鹿島－アラスカの基線長変化年 Baseline Length 1.3 ± 0.5 mm/year 400 200 0 -200 基線長（ｍｍ） -400 1984 1986 1988 1990 1992 1994 年 VLBIVLBI ApplicationsApplications (2)(2) Radio Astronomy : High Resolution Imaging, Astro-dynamics Reference Frame : Celestial / Terrestrial Reference Frame Earth Orientation Parameters, Dynamics of Earth’s Inner Core
[Show full text]
Istituto Di Radioastronomia Inaf
ISTITUTO DI RADIOASTRONOMIA INAF STATUS REPORT October 2007 http://www.ira.inaf.it/ Chapter 1. STRUCTURE AND ORGANIZATION The Istituto di Radioastronomia (IRA) is presently the only INAF structure with divisions distributed over the national territory. Such an organization came about because IRA was originally a part of the National Council of Research (CNR), which imposed the first of its own reforms in 2001. The transition from CNR to INAF began in 2004 and was completed on January 1st , 2005. The Institute has its headquarters in Bologna in the CNR campus area, and two divisions in Firenze and Noto. The Medicina station belongs to the Bologna headquarters. A fourth division is foreseen in Cagliari at the Sardinia Radiotelescope site. The IRA operates 3 radio telescopes: the Northern Cross Radio Telescope (Medicina), and two 32-m dishes (Medicina and Noto), which are used primarily for Very Long Baseline Interferometry (VLBI) observations. The IRA leads the construction of the Sardinia Radio Telescope (SRT), a 64-m dish of new design. This is one of the INAF large projects nowadays. The aims of the Institute comprise: - the pursuit of excellence in many research areas ranging from observational radio astronomy, both galactic and extragalactic, to cosmology, to geodesy and Earth studies; - the design and management of the Italian radio astronomical facilities; - the design and fabrication of instrumentation operating in bands from radio to infrared and visible. Main activities of the various sites include: Bologna: The headquarters are responsible for the institute management and act as interface with the INAF central headquarters in Roma. Much of the astronomical research is done in Bologna, with major areas in cosmology, extragalactic astrophysics, star formation and geodesy.
[Show full text]
EVGA2021 Making VLBI Great Again!
25th European VLBI Group for Geodesy and Astronomy Working Meeting 14-18 March 2021 Cyberspace Information and book of abstracts 2021-03-03 EVGA2021 Making VLBI Great Again! European VLBI Group For Geodesy and Astrometry This page is intentionally left blank. II EVGA2021 information Scientific Organizing Committee (SOC) Simone Bernhart (Reichert GmbH/BKG/MPIfR Bonn) • Sigrid Böhm(Technische UniversitätWien) • Susana Garcia-Espada (Kartverket) • Anastasiia Girdiuk (BKG Frankfurt) • RüdigerHaas (Chalmers University of Technology) • Karine Le Bail (Chalmers University of Technology) • Nataliya Zubko (Finnish Geospatial Research Institute) • Virtual Organizing Committee (VOC) Periklis-Konstantinos Diamantidis (Chalmers University of Technology) • Susana Garcia-Espada (Kartverket) • RüdigerHaas (Chalmers University of Technology) • Karine Le Bail (Chalmers University of Technology) • Series of events during the EVGA2021 Date Time Event 14 March UT 16:00-18:00 Icebreaker party 15 March UT 10:50-17:00 EVGA2021-day-1 16 March UT 11:00-17:00 EVGA2021-day-2 17 March UT 11:00-17:00 EVGA2021-day-3 18 March UT 11:00-14:45 EVGA2021-day-4 18 March UT 14:45-18:30 IVS Analysis Workshop All events will be in Cyberspace, i.e. virtually, and the corresponding information to access the virtual events will be provided via email to the participants. Interested persons not presenting themselves at the EVGA2021, but still interested in attending the oral presentations, are asked to get in to contact with the VOC via email to receive further instructions. III
[Show full text]
The NRAO Program Operating Plan
NATIONAL RADIO ASTRONOMY OBSERVATORY PROGRAM OPERATING PLAN FY 20 12 Associated Univ rsities. Inc. '>1> . r " " , " " , " r 'rr. '°S 9 g[[5 44 t " - , The NRAO Program Operating Plan FY 2012 Revised: March 2012 The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Table of Contents Executive Summary .......................................................................................................................................... 1 1. Overview ..................................................................................................................................................... 3 1.1 Introduction to the Plan .............................................................................................................................. 3 1.2 Structure of the POP ................................................................................................................................... 4 1.3 Financial and Budget Considerations ........................................................................................................ 4 2. Science Programs FY 2012 ...................................................................................................................... 6 3. Optimizing Science Impact: Observatory Science Operations ........................................................ 9 3.1 Shared Services .............................................................................................................................................
[Show full text]
Table of Contents - 1 - - 2
Table of contents - 1 - - 2 - Table of Contents Foreword 5 1. The European Consortium for VLBI 7 2. Scientific highlights on EVN research 9 3. Network Operations 35 4. VLBI technical developments and EVN operations support at member institutes 47 5. Joint Institute for VLBI in Europe (JIVE) 83 6. EVN meetings 105 7. EVN publications in 2007-2008 109 - 3 - - 4 - Foreword by the Chairman of the Consortium The European VLBI Network (EVN) is the result of a collaboration among most major radio observatories in Europe, China, Puerto Rico and South Africa. The large radio telescopes hosted by these observatories are operated in a coordinated way to perform very high angular observations of cosmic radio sources. The data are then correlated by using the EVN correlator at the Joint Institute for VLBI in Europe (JIVE). The EVN, when operating as a single astronomical instrument, is the most sensitive VLBI array and constitutes one of the major scientific facilities in the world. The EVN also co-observes with the Very Long Baseline Array (VLBA) and other radio telescopes in the U.S., Australia, Japan, Russia, and with stations of the NASA Deep Space Network to form a truly global array. In the past, the EVN also operated jointly with the Japanese space antenna HALCA in the frame of the VLBI Space Observatory Programme (VSOP). The EVN plans now to co-observe with the Japanese space 10-m antenna ASTRO-G, to be launched by 2012, within the frame of the VSOP-2 project. With baselines in excess of 25.000 km, the space VLBI observations provide the highest angular resolution ever achieved in Astronomy.
[Show full text]
Book of Abstracts
Dissecting the Universe - Workshop on Results from High-Resolution VLBI Monday 30 November 2015 - Wednesday 02 December 2015 Max-Planck-Institut für Radioastronomie, Bonn, Germany Book of Abstracts Contents GMVA Observations of M87 and Status Report of the GLT Project . 1 Water megamasers at high resolution . 1 Millimeter VLBI Observations of the Twin-Jet-System in NGC1052 . 1 First 3mm-VLBI imaging of the two-sided jet in Cygnus A: zooming into the launching region . 2 New insight into AGN-jets: they are alive! . 2 The connection between the mm VLBI jet and the gamma-ray emission in the blazar CTA102 and the radio galaxy 3C120 . 2 New Developments with the Event Horizon Telescope . 3 Dissecting TeV blazars: Space VLBI study of the BL Lac source Markarian 501 . 3 VLBI Studies of Star Forming Regions using Molecular Masers . 4 The farthest view with overterrestrial baselines . 4 Probing the innermost regions of AGN jets and their magnetic ﬁelds with RadioAstron 4 What has VLBI at the highest resolutions taught us about the VLBI "core"? . 5 The most compact H2O maser spots and their locations in W3 IRS5 . 5 A physical model for the radio and GeV emission from the microquasar LS I +61◦303 6 Detection and Implications of Horizon-Scale Polarization in Sgr A* . 7 The Discovery and Implications of Refractive Substructure for VLBI at the Highest Angular Resolutions . 7 Microarcsecond Structure of the Parsec Scale Jet of the Quasar 3C454.3 . 7 Jets from Water-Disk-Megamaser Galaxies . 8 Unlocking the secrets of PKS 1502+106. Synergies between mm-VLBI and single-dish monitoring .
[Show full text]
NRAO Enews Volume 12, Issue 5 • 13 June 2019
NRAO eNews Volume 12, Issue 5 • 13 June 2019 Upcoming Events NRAO Community Day at UMBC (https://science.nrao.edu/science/meetings/2019/umbc19/index) Jun 13 14, 2019 | Baltimore, MD CASCA 2019 (http://www.physics.mcgill.ca/casca2019/) Jun 17 20, 2019 | Montréal, Québec Radio/mm Astrophysical Frontiers in the Next Decade (http://go.nrao.edu/ngVLA19) Jun 25 27, 2019 | Charlottesville, VA 7th VLA Data Reduction Workshop (http://go.nrao.edu/vladrw) Oct 7 18, 2019 | Socorro, NM ALMA2019: Science Results and CrossFacility Synergies (http://www.eso.org/sci/meetings/2019/ALMA2019Cagliari.html) Oct 14 18, 2019 | Cagliari, Sardinia, Italy Semester 2019B Proposal Outcomes Lewis Ball The NRAO has completed the Semester 2019B proposal review and time allocation process (https://science.nrao.edu/observing/proposal-types/peta) for the Very Large Array (VLA) (https://science.nrao.edu/facilities/evla) and the Very Long Baseline Array (VLBA) (https://science.nrao.edu/facilities/vlba) . For the VLA a single configuration (the D array) will be available in the 19B semester and 124 new proposals were received by the 1 February 2019 submission deadline including one large and sixteen time critical (triggered) proposals. The oversubscription rate (by proposal number) was 2.5 and the proposal pressure (hours requested over hours available) was 2.1, both of which are similar to recent semesters. For the VLBA 27 new proposals were submitted, including two large proposals and one triggered proposal. The oversubscription rate was 2.1 and the proposal pressure was 2.3, both of which are similar to recent semesters.
[Show full text]
Waiting with Baboons
CAREER VIEW NATURE|Vol 455|30 October 2008 MOVERS NETWORKS & SUPPORT Colin Lonsdale, director, Haystack Observatory, Massachusetts Institute of Technology, Sustenance for sustainability Westford, Massachusetts Scientists who seek intensely curiosity-driven research to short- interdisciplinary study could be term goals. Within the next 2 years, 2006–08: Assistant director, the beneficiaries of increasing they plan to recruit at least 10 Haystack Observatory, interest in the emerging field of faculty members, 10–20 graduate Massachusetts Institute of sustainability research, with new students and up to 5 postdocs to Technology university programmes offering tackle technical issues surrounding 1986–2008: Research novel opportunities. Portland State alternative energy sources, scientist, Haystack University in Oregon and Cornell sustainable urban communities Observatory, Massachusetts University in Ithaca, New York, are the and developing the metrics of Institute of Technology most recent entrants to the field. They sustainability. He also hopes to set 1983–86: Research follow the example set by institutions up a visiting faculty programme associate, Pennsylvania State such as the School of Sustainability at to forge national and international University, University Park, Arizona State University in Tempe. connections. Pennsylvania Broadly defined, sustainability Cornell’s Institute for Computational bridges disciplines to determine how Sustainability involves scientists from Colin Lonsdale says radio astronomy is experiencing a to meet the
[Show full text]
Haystack Observatory
Haystack Observatory Haystack Observatory is a multidisciplinary research center located in Westford, MA, 40 miles northwest of the MIT campus. The observatory conducts astronomical studies using radio techniques, geodetic measurements using very long baseline interferometry (VLBI), and atmospheric observations using high-power incoherent scatter radar. An important component of Haystack’s mission is the education of undergraduate and graduate students through research opportunities that make use of the observatory’s facilities. The current priorities of the radio astronomy program at Haystack involve the development of radio arrays operating at low frequencies to study the structure of matter in the universe and the advancement of the astronomical VLBI technique to observe our galaxy and other galaxies. The primary objective of the geodetic VLBI research program is to improve the accuracy of measurements of Earth’s orientation parameters and establish a celestial reference frame for geophysical measurements. The goal of the atmospheric science program is to understand the effects of solar disturbances on Earth’s upper atmosphere using measurements from the observatory’s radars and observations from global positioning satellites. A strong technology and engineering program supports each of the scientific research disciplines. The radio astronomy research program is carried out under the auspices of the Northeast Radio Observatory Corporation (NEROC), a consortium of nine educational and research institutions that includes, in addition to MIT: Boston University, Brandeis University, Dartmouth College, Harvard University, Harvard-Smithsonian Center for Astrophysics, University of Massachusetts, University of New Hampshire, and Wellesley College. Haystack Observatory also supports Lincoln Laboratory’s space surveillance program, and the two share the Westford facilities.
[Show full text]