DOCSLIB.ORG

1997 STATISTICS Cover: Radio Image of the Supernova Remnant W50

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

NATIONAL RADIO O B S S u E M R M V A I R N Y G ASTRONOMY OBSERVATORY 1997 STATISTICS Cover: Radio image of the supernova remnant W50. The image was made with the Very Large Array at 1.4 GHz from a mosaic of 58 individual images. The regions of most intense radio emission are shown in red while regions of lower brightness are colored blue. The W50 remnant is powered by the dying star SS433 seen near the center; helical filaments of radio emission can be seen emanating from SS433. Observers: G. Dubner, F. Mirabel, M. Holdaway, M. Goss NATIONAL RADIO ASTRONOMY OBSERVATORY Observing Summary 1997 Statistics March 1998 SCIENTIFIC HIGHLIGHTS The first VLSI Satellite project, the VLBI Space Observatory Program (VSOP), has been successful. The Japanese HALCA satellite, launched in February, observed the radio source PKS 1519-273 at 1.6 GHz on 22 May, together with the VLBA and VLA. The data were correlated successfully in Socorro on 12 June and an image was produced a few days later. The image, a point source, confirmed the proper operation of the entire system, including the Green Bank ground station and the VLBA correlator. Since mid-1997, VSOP has made a transition from in-orbit checkout to general scientific observing. Nearly 50 scientific observations have been processed by the VLBA correlator and released to the investigators. Several images of compact extragalactic radio sources have been produced at 1.6 and 5 GHz, with considerably higher resolution than is available with ground-only VLBI at the same frequencies. Numerous scientific results from these images are expected to be published over the next year. The 12 Meter Telescope has conducted extensive measures of the Martian CO absorption in support of the Mars Global Surveyor (MGS), which entered Mars orbit on 12 September. The MGS is an orbiter mission to conduct the first global mapping of the surface mineralogy, topology, and magnetic fields, at high-to-medium resolution. The 12 Meter CO data, taken regularly over the past year, and at three-day intervals since September, are used to provide atmospheric sounding measurements of the martian atmosphere in support of the aerobraking maneuvers of the MGC orbiter, which dips into the upper atmosphere in order to circularize its orbit. The CO data provide measures of the dust heating of the lower atmosphere (0-50 km), which in turn provide early warning of associated changes in the atmospheric densities encountered by the MGS orbiter. The CO 2-1 absorption has also produced highly accurate measures of the pressure changes at 70 km altitude, which show a very good correlation with the density changes seen by MGS. For example, the CO data showed cold, dust-free conditions as MGS entered orbit, and also indicated a significant trend of increasing temperatures up to 21 September, as a result of increasing dust loading of the lower atmosphere. It will soon be possible to determine whether the current dust behavior is a short-term phenomenon such as observed during the March-July period, or is the beginning of truly global dust storm activity on Mars. A large HI supershell has been discovered near the Galactic plane in Aquila. Observations with the 140 Foot Telescope show an irregular spherical shell sitting atop a well-defined massive cone which connects to a molecular cloud in the Galactic Plane. The shell extends at least 550 pc up into the Galactic halo. The system requires the energy of 10-100 superaovae over 10 million years for its creation. It is associated with a complex of supemovae, star-forming regions and HE regions, some of which may have been induced by a shock wave related to formation of the supershell. The VLA and VLBA have made the first detection of radio emission from a Gamma-Ray Burster. The gamma-ray burst was detected by the BeppoSAX satellite on 8 May and the VLA observed the region within four hours. Radio emission was first seen on 13 May, and VLBI detection was made on 16 May, yielding a position accurate to less than a milliarcsecond. Continued monitoring shows the object to be variable in both intensity and spectral index, and to have a proper motion no greater than 50 milliarcseconds per year. If the fluctuations are the result of scintillation due to inhomogeneities in the interstellar medium, the angular size of the source in the first few weeks was ~ 3 microarcseconds, a linear size of 1017 cm at a distance of 1028 cm. The subsequent damping of the scintillations is presumed due to relativistic expansion of the fireball to an angular size no longer subject to scintillation. The object is also observed optically, and has a minimum redshift of z = 0.85, thus greatly strengthening the case for cosmological distances to these objects. The long-chain cyanopolyyne species HCnN has been reliably identified in the molecular cloud TMC-1 via observations at the 140 ft telescope of two consecutive transitions (J= 39-38 and J = 38-37). The observations are based on frequencies expected from 2 laboratory work at the Center for Astrophysics. The column density of HCnN is 2.8 x 10" cm" . The abundance of the cyanopolyynes thus decreases smoothly from HC5N to HC,^, the decrement from one to the next being about 6 for the longer carbon chains. This detection of HCnN, a molecule with a molecular weight (147 amu) nearly twice that of the amino acid glycine, demonstrates that detectable quantities of fairly large organic molecules can form in extraterrestrial sources under conditions markedly different from those on Earth. Several programs to study the physical and chemical composition and the evolution of comet Hale-Bopp have been performed at + the 12 Meter Telescope. Studies of CO, CN, CS, H2S, HCO , H2CO, CH3OH and HCN have chronicled the chemical evolution and the temperature of the comet as it approached perihelion. The first detection of HNC has been made in a comet, and yields a ratio [HNC]/[HCN] - 0.5, close to values found in dark clouds. This ratio suggests that Hale-Bopp was formed from pristine interstellar matter and did not undergo much processing in the presolar nebula. The AGN galaxy NGC4258 continued to provide impressive results during 1997. VLBA/VLA observations of the warped disk of H20 molecules surrounding a supermassive object at the galaxy's core have yielded a precise position for the central object, presumably a black hole with 3.5xl07 solar masses. Proper motions have been measured for individual maser spots within the disk. Continuum emission has been detected in the nuclear region, and shows an offset from the calculated position of the central object consistent with the jet model proposed by Blandford and Konigl in 1979. The proper motion detections will allow a trigonometric determination of the distance to NGC4258 to within five percent. OBSERVING HOURS est. est. est. 30 1985 86 87 88 89 90 91 92 93 94 95 96 97 98 99 2000 Calendar Year 140 Foot £2] 12 Meter ^ VLA □ VLBA Figure 1. This figure shows the hours for observing on each telescope during the last decade. Includes astronomical observing, testing, and calibration. DISTRIBUTION OF SCHEDULED OBSERVING TIME 12 Meter 140 Foot VLA VLBA 8-B :• ■ •:•: ■ :* - v< •••■ *.•■ .V V. iV V •*•' SL lU V. M 7 ^ n o o "■^ © :mm m 1 \ 3 ! imm O Wi7 14 1 'm S A 'm'A 'A m, x22 Ji nWi ■§■? ^IIIIH 1988 89 90 91 92 93 94 95 96 97 1988 89 90 91 92 93 94 95 96 97 1988 89 90 91 92 93 94 95 96 97 1993 94 95 96 97 Calendar Year Calendar Year Calendar Year Calendar Year NRAO Staff Y//\ Visitors Kggfl Testing and Calibration Figure 2. These graphs show the number of hours scheduled for testing and calibration, and for observing by the NRAO staff and by visitors on each telescope system. 12 METER RADIO TELESCOPE SUMMARY 100 -- A 80 1 r s n A A i ^ 1 X / i * i / \ ^C 1 JL - ^ r / ^ / \ / \ A / ■\ X * 60 1 A A n A r 1 t J i A f 1 A r l A Z 3 £ - u D: 40 I [ U ULf - Y ^ V Y 20 J V / I 7 \i V l 0 1 ^ L i V i V 1 1 i V * v r <* .- & S v V J i .-• '«** ^ X ?: ^i /' ' j P**' »*»' > !•' V t > J.. A ^ > Calendar Year Observing Installation, Maintenance and Calibration — — Equipment Failure, Weather and Interference Figure 3. This summary for each quarter of the calendar year shows the percentage of the total time in the year (8760 hours) that the telescope was scheduled for observing; for routine calibration, maintenance, and installation of new experiments; and the percentage of time lost due to equipment failure, bad weather, and radio interference. The telescope is removed from service for a period of four to six weeks each summer during the wet season. This period is used for maintenance and upgrading of the instrument. 140 FOOT RADIO TELESCOPE SUMMARY 100 "^ _ ^ M. ^ ^ mm «■ A ^ 80 L^ ^ ▼ % - C ^ - « 60 - - & 40 - - 20 ^k, •s ^ A "•; V, * 4 A .-, • •* ^■^ ■ •« ..- V. .^^^. '^. IT *►-. ,-*•"• Calendar Year Observing Installation, Maintenance and Calibration — — Equipment Failure, Weather and Interference Figure 4. This summary for each quarter of the calendar year shows the percentage of the total time in the year (8760 hours) that the telescope was scheduled for observing; for routine calibration, maintenance, and installation of new experiments; and the percentage of time lost due to equipment failure, bad weather, and radio interference. VERY LARGE ARRAY TELESCOPE SUMMARY 100 - - 80 *> /V ,^, ,B',i \0 - — "^ ^ V ^ ^" "* ^ ■■ s " *" ^ ^ '" -*- 3 60 V - - ou 40 N K s^ •N ^m _ —.
Recommended publications
  • Radio and Millimeter Continuum Surveys and Their Astrophysical Implications

    Radio and Millimeter Continuum Surveys and Their Astrophysical Implications

    The Astronomy and Astrophysics Review (2011) DOI 10.1007/s00159-009-0026-0 REVIEWARTICLE Gianfranco De Zotti · Marcella Massardi · Mattia Negrello · Jasper Wall Radio and millimeter continuum surveys and their astrophysical implications Received: 13 May 2009 c Springer-Verlag 2009 Abstract We review the statistical properties of the main populations of radio sources, as emerging from radio and millimeter sky surveys. Recent determina- tions of local luminosity functions are presented and compared with earlier esti- mates still in widespread use. A number of unresolved issues are discussed. These include: the (possibly luminosity-dependent) decline of source space densities at high redshifts; the possible dichotomies between evolutionary properties of low- versus high-luminosity and of flat- versus steep-spectrum AGN-powered radio sources; and the nature of sources accounting for the upturn of source counts at sub-milli-Jansky (mJy) levels. It is shown that straightforward extrapolations of evolutionary models, accounting for both the far-IR counts and redshift distribu- tions of star-forming galaxies, match the radio source counts at flux-density levels of tens of µJy remarkably well. We consider the statistical properties of rare but physically very interesting classes of sources, such as GHz Peak Spectrum and ADAF/ADIOS sources, and radio afterglows of γ-ray bursts. We also discuss the exploitation of large-area radio surveys to investigate large-scale structure through studies of clustering and the Integrated Sachs–Wolfe effect. Finally, we briefly describe the potential of the new and forthcoming generations of radio telescopes. A compendium of source counts at different frequencies is given in Supplemen- tary Material.
  • 18.465, Revised Again December 6, 2012 Truncation, the Lynden-Bell Estimator, and Galaxy Data

    18.465, Revised Again December 6, 2012 Truncation, the Lynden-Bell Estimator, and Galaxy Data

    18.465, Revised again December 6, 2012 Truncation, the Lynden-Bell estimator, and galaxy data 1. Definitions Suppose there are i.i.d. pairs (Xk,Yk) of variables for k = 1, ..., N where N is unknown to the observer. Within each pair, Xk and Yk are independent positive real variables with distributions F and G respec- tively. In the “truncation” or “left truncation” model, the specific restric- tion is that the pair of values (Xk,Yk) is observed if and only if Yk Xk. Moreover, the index k is not observed. One wants to estimate F≤. Suppose then that we observe (xj, yj), j = 1, ..., n, so that we observe a value of n and know about N at first that N n. Recall the survival function corresponding to F , S(x) 1 F (x),≥ ≡ − 2. The Lynden-Bell estimator Let ξi for i = 1, ..., m be the distinct values of xj. What is called the Lynden-Bell estimator of S(x) is ri (1) Sn(x)= 1 µ − nCn(ξi)¶ ξYi≤x b where ri is the number of j n such that xj = ξi and ≤ n 1 C (s)= 1 . n n {yj <s≤xj } Xj=1 These formulas are as given by Woodroofe (1985, (8)) and Chen et al. (1995, (1)), originating with Lynden-Bell (1971). 3. Absolute and apparent magnitudes for astronomical objects Magnitudes were first assigned in ancient times to stars, with the brightest being assigned first magnitude, a next-brightest category sec- ond magnitude, and so on to the faintest stars visible to the naked eye under good conditions, 6th magnitude.
  • JRASC-2007-04-Hr.Pdf

    JRASC-2007-04-Hr.Pdf

    Publications and Products of April / avril 2007 Volume/volume 101 Number/numéro 2 [723] The Royal Astronomical Society of Canada Observer’s Calendar — 2007 The award-winning RASC Observer's Calendar is your annual guide Created by the Royal Astronomical Society of Canada and richly illustrated by photographs from leading amateur astronomers, the calendar pages are packed with detailed information including major lunar and planetary conjunctions, The Journal of the Royal Astronomical Society of Canada Le Journal de la Société royale d’astronomie du Canada meteor showers, eclipses, lunar phases, and daily Moonrise and Moonset times. Canadian and U.S. holidays are highlighted. Perfect for home, office, or observatory. Individual Order Prices: $16.95 Cdn/ $13.95 US RASC members receive a $3.00 discount Shipping and handling not included. The Beginner’s Observing Guide Extensively revised and now in its fifth edition, The Beginner’s Observing Guide is for a variety of observers, from the beginner with no experience to the intermediate who would appreciate the clear, helpful guidance here available on an expanded variety of topics: constellations, bright stars, the motions of the heavens, lunar features, the aurora, and the zodiacal light. New sections include: lunar and planetary data through 2010, variable-star observing, telescope information, beginning astrophotography, a non-technical glossary of astronomical terms, and directions for building a properly scaled model of the solar system. Written by astronomy author and educator, Leo Enright; 200 pages, 6 colour star maps, 16 photographs, otabinding. Price: $19.95 plus shipping & handling. Skyways: Astronomy Handbook for Teachers Teaching Astronomy? Skyways Makes it Easy! Written by a Canadian for Canadian teachers and astronomy educators, Skyways is Canadian curriculum-specific; pre-tested by Canadian teachers; hands-on; interactive; geared for upper elementary, middle school, and junior-high grades; fun and easy to use; cost-effective.
  • X-Ray Jets Aneta Siemiginowska

    X-Ray Jets Aneta Siemiginowska

    Chandra News Issue 21 Spring 2014 Published by the Chandra X-ray Center (CXC) X-ray Jets Aneta Siemiginowska The Active Galaxy 4C+29.30 Credit: X-ray: NASA/CXC/SAO/A.Siemiginowska et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA Contents X-ray Jets HETG 3 Aneta Siemiginowska 18 David Huenemoerder (for the HETG team) 10 Project Scientist’s Report 20 LETG Martin Weisskopf Jeremy Drake 11 Project Manager’s Report 23 Chandra Calibration Roger Brissenden Larry David Message of Thanks to Useful Web Addresses 12 Harvey Tananbaum 23 The Chandra Team Belinda Wilkes Appointed as CIAO 4.6 13 Director of the CXC 24 Antonella Fruscione, for the CIAO Team Of Programs and Papers: Einstein Postdoctoral Fellowship 13 Making the Chandra Connection 29 Program Sherry Winkelman & Arnold Rots Andrea Prestwich Chandra Related Meetings Cycle 14 Peer Review Results 14 and Important Dates 30 Belinda Wilkes ACIS Chandra Users’ Committee 14 Paul Plucinsky, Royce Buehler, 34 Membership List Gregg Germain, & Richard Edgar HRC CXC 2013 Science Press 15 Ralph Kraft, Hans Moritz Guenther 35 Releases (SAO), and Wolfgang Pietsch (MPE) Megan Watzke The Chandra Newsletter appears once a year and is edited by Paul J. Green, with editorial assistance and layout by Evan Tingle. We welcome contributions from readers. Comments on the newsletter, or corrections and additions to the hardcopy mailing list should be sent to: [email protected]. Spring, 2014 3 X-ray Jets many unanswered questions, including the nature of relativistic jets, jet energetics, particle content, parti- Aneta Siemiginowska cle acceleration and emission processes. Both statis- tical studies of large samples of jets across the entire The first recorded observation of an extragalac- electromagnetic spectrum and deep broad-band imag- tic jet was made almost a century ago.
  • Information Bulletin on Variable Stars

    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

    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).
  • 16Th HEAD Meeting Session Table of Contents

    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
  • Aerosols in Astrophysics Stars Complete Their Cycle of Existence, There R.E.Stencel, C.A

    Aerosols in Astrophysics Stars Complete Their Cycle of Existence, There R.E.Stencel, C.A

    Aerosols in Astrophysics stars complete their cycle of existence, there R.E.Stencel, C.A. Jurgenson & is a wholesale return of modified material T.A. Ostrowski-Fukuda back to the interstellar medium, affecting the The Observatories, University of Denver, next generation of star and planet formation. Department of Physics & Astronomy, Denver, Colorado 80208, USA Submitted: Evolved stars are characterized by surface 2002December30, Email: [email protected] temperatures low enough to allow molecules and solid-phase particles to exist in their ABSTRACT: atmospheres. In contrast to the nearly 6000K surface temperature of the Sun, the Solid phase material exists in low density kinetic temperatures of evolved stars may astrophysical environments, from stellar range between 2000K near their “surfaces” atmospheres to interstellar clouds, from to a few hundred K in their circumstellar current times to early phases of the universe. envelopes [CSE] at a few stellar radii We consider the origin, composition and distance. Time-dependent phase transitions evolution of solid phase materials in the from ionized plasma to cold, solid state are particular case of stellar outer atmospheres, observed, spectroscopically, to exist. as representative of many conditions. Also considered are the dynamics and interactions Some terminology may be helpful for the in circumstellar and galactic environments. reader not already acquainted with stellar Finally, new observational prospects for evolution. Solar mass stars are predicted to spectroscopy, polarimetry and leave the hydrogen-fusing “main sequence” interferometry are discussed. after approximately ten billion years, and progress through a rapid series of internal changes during what is known as the red 1.0 INTRODUCTION giant and asymptotic giant branch [RGB, AGB] phases, lasting one percent of the Solid phase material can be found nearly main sequence lifetime.
  • Patrick Moore's Practical Astronomy Series

    Patrick Moore's Practical Astronomy Series

    Patrick Moore’s Practical Astronomy Series Other Titles in this Series Navigating the Night Sky Astronomy of the Milky Way How to Identify the Stars and The Observer’s Guide to the Constellations Southern/Northern Sky Parts 1 and 2 Guilherme de Almeida hardcover set Observing and Measuring Visual Mike Inglis Double Stars Astronomy of the Milky Way Bob Argyle (Ed.) Part 1: Observer’s Guide to the Observing Meteors, Comets, Supernovae Northern Sky and other transient Phenomena Mike Inglis Neil Bone Astronomy of the Milky Way Human Vision and The Night Sky Part 2: Observer’s Guide to the How to Improve Your Observing Skills Southern Sky Michael P. Borgia Mike Inglis How to Photograph the Moon and Planets Observing Comets with Your Digital Camera Nick James and Gerald North Tony Buick Telescopes and Techniques Practical Astrophotography An Introduction to Practical Astronomy Jeffrey R. Charles Chris Kitchin Pattern Asterisms Seeing Stars A New Way to Chart the Stars The Night Sky Through Small Telescopes John Chiravalle Chris Kitchin and Robert W. Forrest Deep Sky Observing Photo-guide to the Constellations The Astronomical Tourist A Self-Teaching Guide to Finding Your Steve R. Coe Way Around the Heavens Chris Kitchin Visual Astronomy in the Suburbs A Guide to Spectacular Viewing Solar Observing Techniques Antony Cooke Chris Kitchin Visual Astronomy Under Dark Skies How to Observe the Sun Safely A New Approach to Observing Deep Space Lee Macdonald Antony Cooke The Sun in Eclipse Real Astronomy with Small Telescopes Sir Patrick Moore and Michael Maunder Step-by-Step Activities for Discovery Transit Michael K.
  • The Norris Survey of the Corona Borealis Supercluster: II. Galaxy

    The Norris Survey of the Corona Borealis Supercluster: II. Galaxy

    The Norris Survey of the Corona Borealis Supercluster: II. Galaxy Evolution with Redshift and Environment Todd A. Small1 and Wallace L.W. Sargent Palomar Observatory, California Institute of Technology, Pasadena, CA 91125 Electronic mail: [email protected], [email protected] Donald Hamilton Max-Planck-Institut f¨ur Astronomie, K¨onigstuhl 17, Heidelberg D-69117, Germany Electronic mail: [email protected] ABSTRACT We measure the field galaxy luminosity function (LF) as a function of color and redshift from z =0 to z =0.5 using galaxies from the Norris Survey of the Corona Borealis Supercluster. The data set consists of 603 field galaxies with m m 0 < z ≤ 0.5 and spans a wide range in apparent magnitude (14.0 ∼<r ∼< 21.5 ), although our field galaxy LF analysis is limited to 493 galaxies with r ≤ 20.0m. We use the observed g − r colors of the galaxies to compute accurate corrections to the rest BAB and r bands. We find that our local r-band LF, when normalized to counts in high galactic latitude fields, agrees well with the local LF measured in the Las Campanas Redshift Survey. Our BAB-band local LF, however, does not match the bj-band LF from the Stromlo/APM survey, having a normalization 1.6 times higher. We see compelling evidence that the BAB-band field galaxy LF evolves with redshift. The evolution is strongest for arXiv:astro-ph/9705021v1 5 May 1997 the population of star-forming galaxies with [O II] λ3727 rest-frame equivalent widths greater than 10A.˚ The population of red, quiescent galaxies shows no sign of evolution to z = 0.5.
  • A Catalogue of Zeldovich Pancakes

    A Catalogue of Zeldovich Pancakes

    A Catalogue of Zeldovich Pancakes Mikkel O. Lindholmer Supervisor: Steen H. Hansen Master’s thesis, submitted on October 18, 2015 Dark Cosmology Centre, Niels Bohr Institute, Juliane Maries Vej 30, 2100 Copenhagen, Denmark Abstract Using the standard cold dark matter model ΛCDM, it is predicted that there will be small fluctuations in the primordial energy density. These fluctuations are expected to lead to a cosmic web [1] under the influence of gravity and time. This web will consist of dense galaxy clusters interlinked by less dense two-dimensional walls, so called Zeldovich pancakes [2], and one-dimensional filaments. Galaxy clusters and filaments have been observed for a long time, but only recently have Zeldovich pancakes been observed outside of simulations [6]. The reason these have only recently been observed is because they are much less dense than filaments and clusters, to the point of being hard to differentiate from the average density of their environs [4,5]. Using the method we invented in Falco et. al [6] to find 2 pancakes as a basis, I create a fully automatic program capable of finding pancakes without human input, in galaxy cluster widely different from each other. I apply this program to the Abell galaxy clusters and using the SDSS catalogue I check for potential pancakes in the galaxy clusters. While most of the cluster are contained in the SDSS many of the clusters are only partially covered. I try to make the program compensate for this and manage to create the first catalogue of Zeldovich pancakes by finding 197 of them in 113 different clusters.
  • On the Hunt for Excited States

    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.