DOCSLIB.ORG

1. Introduction

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
1. Introduction THE ASTROPHYSICAL JOURNAL, 560:49È71, 2001 October 10 V ( 2001. The American Astronomical Society. All rights reserved. Printed in U.S.A. THE FARTHEST KNOWN SUPERNOVA: SUPPORT FOR AN ACCELERATING UNIVERSE AND A GLIMPSE OF THE EPOCH OF DECELERATION1 ADAM G. RIESS,2 PETER E. NUGENT,3 RONALD L. GILLILAND,2 BRIAN P. SCHMIDT,4 JOHN TONRY,5 MARK DICKINSON,2 RODGER I. THOMPSON,6 TAMAS BUDAVARI,7 STEFANO CASERTANO,2 AARON S. EVANS,8 ALEXEI V. FILIPPENKO,9 MARIO LIVIO,2 DAVID B. SANDERS,5 ALICE E. SHAPLEY,10 HYRON SPINRAD,9 CHARLES C. STEIDEL,10 DANIEL STERN,11 JASON SURACE,12 AND SYLVAIN VEILLEUX13 Received 2001 March 12; accepted 2001 May 18 ABSTRACT We present photometric observations of an apparent Type Ia supernova (SN Ia) at a redshift of D1.7, the farthest SN observed to date. The supernova, SN 1997†, was discovered in a repeat observation by the Hubble Space Telescope (HST ) of the Hubble Deep Field-North (HDF-N) and serendipitously moni- tored with NICMOS on HST throughout the Thompson et al. Guaranteed-Time Observer (GTO) cam- paign. The SN type can be determined from the host galaxy type: an evolved, red elliptical lacking enough recent star formation to provide a signiÐcant population of core-collapse supernovae. The classi- Ðcation is further supported by diagnostics available from the observed colors and temporal behavior of the SN, both of which match a typical SN Ia. The photometric record of the SN includes a dozen Ñux measurements in the I, J, and H bands spanning 35 days in the observed frame. The redshift derived from the SN photometry, z \ 1.7 ^ 0.1, is in excellent agreement with the redshift estimate of \ ^ z 1.65 0.15 derived from theU300 B450 V606 I814 J110 J125 H160 H165 Ks photometry of the galaxy. Optical and near-infrared spectra of the host provide a very tentative spectroscopic redshift of 1.755. Fits to observations of the SN provide constraints for the redshift-distance relation of SNe Ia and a powerful test of the current accelerating universe hypothesis. The apparent SN brightness is consistent with that ) B ) B 2 expected in the decelerating phase of the preferred cosmological model,M 1/3, " 3. It is inconsis- tent with gray dust or simple luminosity evolution, candidate astrophysical e†ects that could mimic pre- vious evidence for an accelerating universe from SNe Ia at z B 0.5. We consider several sources of potential systematic error, including gravitational lensing, supernova misclassiÐcation, sample selection bias, and luminosity calibration errors. Currently, none of these e†ects alone appears likely to challenge our conclusions. Additional SNe Ia at z [ 1 will be required to test more exotic alternatives to the accel- erating universe hypothesis and to probe the nature of dark energy. Subject headings: cosmology: observations È supernovae: general On-line material: color Ðgure 1. INTRODUCTION 1 Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. The unexpected faintness of Type Ia supernovae (SNe Ia) 2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, at z B 0.5 provides the most direct evidence that the expan- MD 21218; ariess=stsci.edu. sion of the universe is accelerating, propelled by ““ dark 3 Lawrence Berkeley National Laboratory, Berkeley, CA 94720. energy ÏÏ (Riess et al. 1998; Perlmutter et al. 1999). This 4 Mount Stromlo and Siding Spring Observatories, Private Bag, Weston Creek P.O. 2611, Australia. conclusion is supported by measurements of the character- 5 Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, istic angular scale of Ñuctuations in the cosmic microwave Honolulu, HI 96822. background (CMB) that reveal a total energy density well in 6 Steward Observatory, University of Arizona, Tucson, AZ 85721. excess of the fraction attributed to gravitating mass (de Ber- 7 Department of Physics and Astronomy, The Johns Hopkins Uni- versity, Baltimore, MD 21218, and Department of Physics,Eotvos Uni- nardis et al. 2000; Balbi et al. 2000; Ja†e et al. 2001). versity, Budapest, Pf. 32, Hungary, H-1518. However, contaminating astrophysical e†ects can imitate 8 Department of Physics and Astronomy, State University of New York the evidence for an accelerating universe. A pervasive screen (SUNY) at Stony Brook, NY 11794-3800. of gray dust could dim SNe Ia with little telltale reddening 9 Department of Astronomy, University of California, Berkeley, CA apparent from their observed colors (Aguirre 1999a, 1999b; 94720-3411. 10 Palomar Observatory, California Institute of Technology, Mail Code Rana 1979, 1980). Although the Ðrst exploration of a distant 105-24, Pasadena, CA 91125. SN Ia at near-infrared (NIR) wavelengths provided no evi- 11 Jet Propulsion Laboratory, California Institute of Technology, Mail dence of nearly gray dust, more data are needed to perform Code 169-327, Pasadena, CA 91109. a deÐnitive test (Riess et al. 2000). 12 SIRTF Science Center, California Institute of Technology, Mail Code 314-6, Pasadena, CA 91125. A more familiar challenge to the measurement of the 13 Department of Astronomy, University of Maryland, College Park, global acceleration or deceleration rate is luminosity evolu- MD 20742. tion (Sandage & Hardy 1973). The lack of a complete theo- 49 50 RIESS ET AL. Vol. 560 retical understanding of SNe Ia and an inability to identify covered an SN Ia at z \ 1.2 (SN 1999fv) as well as at least their speciÐc progenitor systems undermines our ability to one more at z B 1.05 (Tonry et al. 1999; Coil et al. 2000). predict with conÐdence the direction or degree of lumi- These data sets, while currently lacking the statistical power nosity evolution(HoÑich, Wheeler, & Thielemann 1998; to discriminate between cosmological and astrophysical Umeda et al. 1999a, 1999b; Livio 2000; Drell, Loredo, & e†ects, are growing and may provide the means to break Wasserman 2000; Pinto & Eastman 2000; Yungelson & degeneracies in the future. Livio 2000). The weight of empirical evidence appears to In early 1998, Gilliland & Phillips (1998) reported the disfavor evolution as an alternative to dark energy as the detection of two SNe, SN 1997† and SN 1997fg, in a reob- cause of the apparent faintness of SNe Ia at z B 0.5 (see servation of the Hubble Deep Field-North (HDF-N) with Riess 2000 for a review). However, the case against evolu- WFPC2 through the F814W Ðlter. The elliptical host of SN tion remains short of compelling. 1997† indicated that this supernova was ““ most probably a The extraordinary claim of the existence of dark energy SN Ia. .[at] the greatest distance reported previously for requires a high level of evidence for its acceptance. Fortu- SNe,ÏÏ but the observations at a single epoch and in a single nately, a direct and deÐnitive test is available. It should be band were insufficient to provide useful constraints on the possible to discriminate between cosmological models and SN and, hence, to perform cosmological tests (Gilliland, ““ impostors ÏÏ by tracing the redshift-distance relation to Nugent, & Phillips 1999, hereafter GNP99). redshifts greater than one. Here we report additional, serendipitous observations of SN 1997† obtained in the Guaranteed-Time Observer 1.1. T he Next Redshift Octave and the Epoch (GTO) NICMOS campaign (Thompson et al. 1999) and in of Deceleration the General Observer (GO) program 7817 (M. Dickinson et If the cosmological acceleration inferred from SNe Ia is al. 2001, in preparation), as well as spectroscopy of the host. real, it commenced rather recently, at 0.5 \ z \ 1. Beyond The combined data set provides the ability to put strong these redshifts, the universe was more compact and the constraints on the redshift and distance of this supernova attraction of matter dominated the repulsion of dark and shows it to be the highest redshift SN Ia observed (to energy. At z [ 1, the expansion of the universe should have date). These measurements further provide an opportunity been decelerating (see Filippenko & Riess 2000). The to perform a new and powerful test of the accelerating uni- observable result at z º 1 would be an apparent increased verse by probing its preceding epoch of deceleration. brightness of SNe Ia relative to what is expected for a non- In ° 2 of this paper, we describe the observations of the decelerating universe. However, if the apparent faintness of SN and its host in the HDF-N and report photometry of SNe Ia at z B 0.5 is caused by dust or simple evolution, SNe the SN from the NICMOS campaign. In ° 3, we analyze the Ia at z [ 1 should appear fainter than expected from decel- observations to constrain the SN parameters: redshift, erating cosmological models. More complex param- luminosity, age of discovery, and distance. The constraints eterizations of evolution or extinction that can match both are used to extend the distance-redshift relation of SNe Ia to the accelerating and decelerating epochs of expansion z [ 1 and to discriminate between cosmological models and would require a higher order of Ðne-tuning and are there- contaminating astrophysical e†ects. Section 4 contains a fore less plausible. discussion of the systematic uncertainties in our measure- Measuring global deceleration at z [ 1 provides addi- ments and their implications. We summarize our Ðndings tional cosmological beneÐts. To constrain the equation of in ° 5. state of dark energy (and distinguish a cosmological con- stant from the decaying scalar Ðelds described by the 2. OBSERVATIONS ““ quintessence ÏÏ hypothesis; Peebles & Ratra 1988; Cald- well,Dave, & Steinhardt 1998), it is necessary to break 2.1. T he Discovery of SN 1997† degeneracies that exist between the global densities of mass Between 1997 December 23 and December 26, Gilliland and dark energy.
Load more

Recommended publications
  • Newsletter I
    te voLUMEtd NO3 + AUTUMN 19I}9 THE NEWSLETTER I Patt of one discovery ptate of Pluto in the constellation Gemini takzn on January 29, D3A. The arow points to Plttto (about 15th magnitude). The bight star is Delta Geminorum. South is at the top and west at the left. (photo coufiesy Clyde Tombaugh) Discoverer of Pluto to Speak Dr. Hazel Ross A special treat is in store for us this Fall when Dr. Ctyde Dr. Tombaugh was born and raised on a farm, first in Tombaugh, discoverer of the planet Pluto, will give the Illinois and later in Kansas. tnspired by an uncle who was Chesley Bonestell Memorial L,ecture on September 23. As something of an amateur astronomer, and encouraged by one contemporary writer has pointed out, "More people have his father, he developed a keen interest in astronomy as a walked on the moon than have discovered planets. In fact, teenager. [,ater, using a f-inch reflector he had made only two other individuals in history have actually discovered himself, he studied Mars and Jupiter and sent drawings of new planets. Dr. Tombaugh is the third, and is still with us." what he had seen to Lowell Observatory in the hopes of obtaining a job. It turned out that the Lowetl astronomers Dr. Tombaugh had just turned 24 when, on February were looking for a young, aspiring astronomer to undertake a 18, 1930, he made the momentous discovery that rocked the search for a new planet beyond Neptune using the world. He had been working at the Lowell Observatory for observatory's new 13-inch camera.
    [Show full text]
  • High-Resolution Observations of the Spatial and Velocity Distribution of Cometary Hydrogen
    Lunar and Planetary Institute, Houston, 1992 N 7 HIGH-RESOLUTION OBSERVATIONS OF THE SPATIAL AND VELOCITY DISTRIBUTION OF COMETARY HYDROGEN Michael E. Brown and Hyron Spinrad Dept. of Astronomy, University of California, Berkeley, CA ABSTRACT We have obtained high velocity and spatial resolution long-slit H<x spectra of comets Austin (1989cl) and Levy (1990c). Spectra of both comets clearly show the existence of a low velocity thermalized component of hydrogen gas. The amount of slow hydrogen is estimated for comet Austin. The Levy spectrum shows an unusual high-velocity spatially- confined blob of hydrogen emission of unknown origin. INTRODUCTION H<_ 6562/_ emission has been observed in comets since Kohoutek (Huppler et al. 1975, Magee-Sauer 1988). Although the excitation mechanism is weak - Ha emission is produced by fluorescence following solar Ly_ excitation of cometary hydrogen - Ho_ is observable because hydrogen is the most abundantly produced and longest-lived species in cometary comae. Hydrogen is produced primarily by photodissociation of water through the following reactions (Crovisier 1989): H20 + hv -+ H + OH. (1) OH + hv ---+H + O. (2) In reaction (1) the typical hydrogen ejection velocity is about 18 km/sec, while in reaction (2) the typical velocity is about 8 km/sec. Models of the hydrogen coma have also suggested the existence of a slow (_ 2 km/sec) thermalized component caused by hydrogen-water collision in the dense inner coma (Combi and Smyth 1987). High resolution spectroscopy of Ho_ should be able to disentangle the different velocity components of the hydrogen coma. Previous spectroscopy, using Fabry-Perot methods (Huppler et aI.
    [Show full text]
  • Brenda L. Frye − C. V
    Brenda L. Frye − C. V. Contact Department of Astronomy/Steward Observatory Tel.: (520) 626-1857 Information University of Arizona e-mail: [email protected] 933 N Cherry Ave Tucson, AZ 85718 Research Observational Cosmology including (but not limited to): galaxy formation & Interests evolution, gravitational lensing, intergalactic medium, high redshift galaxies, structure of the Milky Way, spectroscopy, and data analysis techniques Chronology of University of California at Berkeley, Ph. D., Astrophysics, May 1999, Education Thesis: \A Faint Galaxy Redshift Survey behind Massive Clusters," Advisor: Prof. Hyron Spinrad University of California at Berkeley, M. S., Astrophysics, May 1995 University of Arizona, B. S. Astronomy, B. S. Physics, Magna cum Laude, Dec 1991 Thesis: \MMT Absorption Spectroscopy towards High Redshift QSOs" Advisor: Prof. Jill Bechtold Chronology of University of Arizona Employment Assistant Astronomer, Continuing-eligible status (Jan 2014 - present) Assistant Astronomer & Lecturer (Jan 2011 - Dec 2013) State University of New York at Stony Brook Visiting Professor (Oct 2011- Dec 2011) University of San Francisco (USF) Tenure-track Assistant Professor Department of Physics & Astronomy (Sep 2009 - Sep 2011) Dublin City University (DCU) Fixed Term Lecturer (Jan 2005-Sept 2008) & Research Fellow (Oct 2008 - Aug 2009) (Funded and supervised Ph. D. and undergraduate students, full teaching load, program development & service) Princeton University Council of Science & Technology Postdoctoral Fellow (Sept 2001 - Dec 2004)
    [Show full text]
  • Index to JRASC Volumes 61-90 (PDF)
    THE ROYAL ASTRONOMICAL SOCIETY OF CANADA GENERAL INDEX to the JOURNAL 1967–1996 Volumes 61 to 90 inclusive (including the NATIONAL NEWSLETTER, NATIONAL NEWSLETTER/BULLETIN, and BULLETIN) Compiled by Beverly Miskolczi and David Turner* * Editor of the Journal 1994–2000 Layout and Production by David Lane Published by and Copyright 2002 by The Royal Astronomical Society of Canada 136 Dupont Street Toronto, Ontario, M5R 1V2 Canada www.rasc.ca — [email protected] Table of Contents Preface ....................................................................................2 Volume Number Reference ...................................................3 Subject Index Reference ........................................................4 Subject Index ..........................................................................7 Author Index ..................................................................... 121 Abstracts of Papers Presented at Annual Meetings of the National Committee for Canada of the I.A.U. (1967–1970) and Canadian Astronomical Society (1971–1996) .......................................................................168 Abstracts of Papers Presented at the Annual General Assembly of the Royal Astronomical Society of Canada (1969–1996) ...........................................................207 JRASC Index (1967-1996) Page 1 PREFACE The last cumulative Index to the Journal, published in 1971, was compiled by Ruth J. Northcott and assembled for publication by Helen Sawyer Hogg. It included all articles published in the Journal during the interval 1932–1966, Volumes 26–60. In the intervening years the Journal has undergone a variety of changes. In 1970 the National Newsletter was published along with the Journal, being bound with the regular pages of the Journal. In 1978 the National Newsletter was physically separated but still included with the Journal, and in 1989 it became simply the Newsletter/Bulletin and in 1991 the Bulletin. That continued until the eventual merger of the two publications into the new Journal in 1997.
    [Show full text]
  • The Large Area Lyman Alpha Survey
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server The New Era of Wide-Field Astronomy ASP Conference Series, Vol. ???, 2001 ed.R.G.Clowes The Large Area Lyman Alpha Survey James E. Rhoads Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 USA Sangeeta Malhotra Johns Hopkins University Arjun Dey & Buell T. Jannuzi National Optical Astronomy Observatory Daniel Stern NASA Jet Propulsion Laboratory Hyron Spinrad University of California, Berkeley Abstract. The Lyman-α line is expected to be strong in the presence of active star formation and the absence of dust, making it a good tool for finding chemically primitive galaxies in the early universe. We report on a new survey for high redshift Lyman-α sources, the Large Area Lyman Alpha (LALA) survey. Our survey achieves an unprecedented combina- tion of volume and sensitivity by using narrow-band filters on the new 81922 pixel CCD Mosaic Camera at the 4 meter Mayall telescope of Kitt Peak National Observatory. Well-detected sources with flux and equivalent width matching known high redshift Lyman-α galaxies have an observed surface density corre- sponding to 11000 700 per square degree per unit redshift at z =4:5. Early spectroscopic± followup from the Keck telescope suggests that 1=3 of these are actually at z 4:5, and has confirmed five z>4 Lyman-∼ α emitters so far. Combining≈ our photometric survey with spectroscopic results, we estimate a net density of 4000 Lyman-α emitters per square degree per unit redshift at z 4:5.∼ The star formation rate density (es- timated both from UV continuum≈ and from line emission) is comparable to that of the Lyman break galaxy population within present uncertain- ties.
    [Show full text]
  • Rudolph Minkowski Was an Outstanding Ob- Servational Astronomer and Astrophysicist
    NATIONAL ACADEMY OF SCIENCES R U D O L P H M INKO W SKI 1895—1976 A Biographical Memoir by DO N A L D E . O STER BROCK Any opinions expressed in this memoir are those of the author(s) and do not necessarily reflect the views of the National Academy of Sciences. Biographical Memoir COPYRIGHT 1983 NATIONAL ACADEMY OF SCIENCES WASHINGTON D.C. RUDOLPH LEO BERNHARD MINKOWSKI May 28, 1895-January 4, 1976 BY DONALD E. OSTERBROCK UDOLPH MINKOWSKI was born in Germany near the end R of the last century and died in California during the final quarter of this century. He was trained as a laboratory physicist, but worked most of his life as an observational astronomer. Using the largest optical telescopes in the world, he made important contributions to nearly every branch of nebular and extragalactic astronomy, but his most important contribution of all was to the identification and interpretation of cosmic radio sources. His monument is the National Geographic Society-Palomar Observatory Sky Survey. He guided, encouraged, and counseled a generation of radio and optical astronomers. Minkowski was born in Strassburg, then part of Germany, on May 28, 1895. His grandfather had hurriedly moved his family to Konigsberg from their native Russia less than twenty-five years before to escape the policy of anti-Semitic persecution adopted by the Czar's government. Rudolph's father Oskar, educated in Konigsberg, became a physician, and at the time of Rudolph's birth he was a well-known pathologist on the Strassburg University medical faculty. His research had played a very important part in understanding the causes of diabetes.
    [Show full text]
  • Cycle 10 Approved Programs
    March 2001 • Volume 18, Number 1 SPACE TELESCOPE SCIENCE INSTITUTE Highlights of this Issue: • Grants Management System — page 3 • NGST News — page 6 • IRAF and Python Newsletter — page 19 Astronomer’s Proposal Tools Steve Lubow, [email protected] TScI is developing a new • The Bright Object Tool will allow generation of proposal users to check proposed observations Cycle 10 S preparation tools called for instrumental health-and-safety, as the Astronomer’s Proposal Tools well as science problems (such as (APT).These tools are based on the bleeding). The tool will allow users to Who got time on HST to do what ... Scientist’s Expert Assistant (SEA) display the results graphically in the project which began in 1997 at the VTT or read the results in a table. How the selection process worked ... Advanced Architectures and Automa- • Exposure time calculators will be tion Branch of Goddard Space Flight enhanced to provide graphical Center. The APT aims to improve the displays, such as exposure time as a proposal preparation process in order function of signal to noise. page 11 Approved to provide users with a more intuitive, visual, and interactive experience by • Spreadsheet-like editors will be means of state of the art technology. provided for users to enter proposal Programs Another goal is to make these tools continued page 3 generic so that they can be easily shared for use in creating proposal preparation systems by other observatories. Tools that are currently under 10 development are: • The Visual Target Tuner (VTT) was initially released in June, 2000. This tool displays HST apertures superim- posed on sky images (right).
    [Show full text]
  • 2016 Newsletter
    1 BERKELEY ASTRONOMY UNIVERSITY OF CALIFORNIA AT BERKELEY WINTER 2016 Astronomy in the News For full versions of news articles, visit news.berkeley.edu CONTENTS Astromony in the News ...................1 SUPERMASSIVE BLACK LONG-TERM, HI-RES Chair’s Message ................................4 HOLES MAY BE LURKING TRACKING OF ERUPTIONS Getting to know new faculty ..........4 EVERYWHERE IN THE ON JUPITER’S MOON IO Faculty awards and highlights ....... 5 UNIVERSE OCTOBER 20, 2016–Bob Sanders, Media Retirements ........................................6 APRIL 6, 2016–Bob Sanders, Media Relations Relations Leuschner Observatory Update ...7 Evening with the Stars .....................7 A near-record supermassive black hole Jupiter’s moon Io continues to be the most discovered in a sparse area of the local volcanically active body in the solar system, Undergrad Symposium ...................7 universe indicate that these monster as documented by the longest series of Student Prizes and Awards ............8 objects — this one equal to 17 billion frequent, high-resolution observations of Sackler Lecture .................................9 suns — may be more common than the moon’s thermal emission ever obtained. In Memoriam .....................................9 once thought, according to UC Berkeley Using near-infrared adaptive optics on two Astro Nights .......................................9 astronomers. of the world’s largest telescopes — the Upcoming Events ...........................10 Until now, the biggest supermassive black 10-meter Keck II and the 8-meter Gemini Give to Astronomy .........................10 holes — those with masses at or near 10 North, both located near the summit of billion times that of our sun — have been the dormant volcano Maunakea in Hawaii — UC Berkeley astronomers tracked 48 over time, as if one triggered another 500 found at the cores of very large galaxies in kilometers away.
    [Show full text]
  • 1. Introduction
    THE ASTROPHYSICAL JOURNAL, 560:49È71, 2001 October 10 V ( 2001. The American Astronomical Society. All rights reserved. Printed in U.S.A. THE FARTHEST KNOWN SUPERNOVA: SUPPORT FOR AN ACCELERATING UNIVERSE AND A GLIMPSE OF THE EPOCH OF DECELERATION1 ADAM G. RIESS,2 PETER E. NUGENT,3 RONALD L. GILLILAND,2 BRIAN P. SCHMIDT,4 JOHN TONRY,5 MARK DICKINSON,2 RODGER I. THOMPSON,6 TAMA S BUDAVA RI,7 STEFANO CASERTANO,2 AARON S. EVANS,8 ALEXEI V. FILIPPENKO,9 MARIO LIVIO,2 DAVID B. SANDERS,5 ALICE E. SHAPLEY,10 HYRON SPINRAD,9 CHARLES C. STEIDEL,10 DANIEL STERN,11 JASON SURACE,12 AND SYLVAIN VEILLEUX13 Received 2001 March 12; accepted 2001 May 18 ABSTRACT We present photometric observations of an apparent Type Ia supernova (SN Ia) at a redshift of D1.7, the farthest SN observed to date. The supernova, SN 1997†, was discovered in a repeat observation by the Hubble Space Telescope (HST ) of the Hubble Deep Field-North (HDF-N) and serendipitously moni- tored with NICMOS on HST throughout the Thompson et al. Guaranteed-Time Observer (GTO) cam- paign. The SN type can be determined from the host galaxy type: an evolved, red elliptical lacking enough recent star formation to provide a signiÐcant population of core-collapse supernovae. The classi- Ðcation is further supported by diagnostics available from the observed colors and temporal behavior of the SN, both of which match a typical SN Ia. The photometric record of the SN includes a dozen Ñux measurements in the I, J, and H bands spanning 35 days in the observed frame.
    [Show full text]
  • Berkeley Newsletter (Pdf File)
    VOL. 3 / NO. 1 FALL 2005 A RENAISSANCE IN GAMMA-RAY BURST RESEARCH THE STUDY OF GAMMA-RAY BURSTS fraction of supernovae also produce NEW CLUES TO THE ORIGIN OF (GRBs), which are Nature’s strongest detectable bursts of gamma-rays. Just what SHORT-HARD BURSTS explosions, is enjoying a rebirth owing to determines this bifurcation is not well On May 8, 2005, the SWIFT satellite the launch (November 2004) of NASA’s understood, but may be related to the spin of discovered the short-hard GRB 050509b, SWIFT satellite. Berkeley astronomers are the progenitor system or to the type of and relayed an accurate position from its X- taking a leading role in new developments central object created during collapse phase Ray detector to the ground in real-time. We with ground-based infrared telescope (a neutron star, for most, a black hole for a quickly marshaled an imaging and observations of GRBs following alerts from few). Professor Eliot Quataert and former spectroscopy campaign on the Keck SWIFT via internet. postdoc Todd Thompson are studying the telescopes in Hawaii, the WIYN 3.5m GRBs were discovered serendipitously in details of some of the “central engine” telescope in Arizona, the PAIRITEL 1.3m in 1967 by military satellites, and their origin models for long-duration GRBs. Arizona, and the Gemini 8m in Hawaii. remained a complete mystery for 30 years. In While great strides continue to be made PAIRITEL is the 1.3 meter Peters fact, astronomers did not even know their in understanding long-soft bursts, the Automated Infrared Imaging telescope on distances — in the solar system, or at the “Afterglow Revolution” has not been kind Mt.
    [Show full text]
  • \ ...Marcia Bartusiak
    The Endless Mantra: Innovation at the Keck Observatory by Monica Godha Bobra B.A. Astronomy Boston University, 2004 B.S. Communication Boston University, 2004 Submitted to the Program in Writing and Humanistic Studies in Partial Fulfillment of the Requirements for the Degree of Master of Science in Science Writing at the Massachusetts Institute of Technology September 2005 ( 2005 Monica Godha Bobra. All rights reserved. The author hereby grants to MIT permission to reproduce and to distribute publicly paper and electronic copies of this thesis document in whole or in part. Signatureof Author........ .................. ..... .. ........... ...... .................................... GraduateProgram in Science Writing June 1, 2005 \ .......................Marcia Bartusiak Visiting Profe sor of Writing and Humanistic Studies Thesis Supervisor Accepted by ................................................. Robert Kanigel Director of Graduate Program in Science Writing Professor of Science Writing A"CHIVES The Endless Mantra: Innovation at the Keck Observatory by Monica Godha Bobra Submitted to the Department of Writing and Humanistic Studies on June 1, 2005 in partial fulfillment of the requirements for the Degree of Master of Science in Science Writing ABSTRACT A study of historical, current, and future developments at the Keck Observatory revealed a thriving philosophy of innovation. Intended to defy obsoletion and keep the observatory competitive over long time scales, this philosophy continues to resonate with Keck Observatory scientists. The Keck Observatory consists of two 1 0-meter telescopes situated near the apex of Mauna Kea on the big island of Hawaii. Three main innovations keep the observatory competitive. The observatory contains the first modem active optics-controlled segmented primary mirror, principally designed by Dr. Jerry Nelson. Though it currently reigns as the world's largest aperture at 10 meters, monolithic mirror supporters still question its viability.
    [Show full text]
  • The Origin and Abundances of the Chemical Elements
    UC Irvine UC Irvine Previously Published Works Title The origin and abundances of the chemical elements Permalink https://escholarship.org/uc/item/86s95592 Journal Reviews of Modern Physics, 47(4) ISSN 0034-6861 Author Trimble, V Publication Date 1975 DOI 10.1103/RevModPhys.47.877 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California The origin and abundances of the cheriiical eleriients*& Virginia Trimble~ Astronomy Program, University of Maryland, College Park, Maryland 20742 and Department of Physics, University of California, IrvineC, alifornia 92664 A NATO Advanced Studies Institute on the Origins and Abundances of the Chemical Elements was held at the Institute of Astronomy, Cambridge~ England from 23 July to 9 August 1974. The problems discussed there are the basis for this review. Three major areas can be identified. First, the normal distribution of chemical and isotopic abundances and deviations from it must be determined observationally. Second, the relevant nuclear processes and their sites and products must be identified. Third, a model of the evolution of galaxies which ixsgludes the relevant processes and produces the observed abundances must be formulated. There has been rapid progress recently in all three of these areas. CONTENTS F. Other Galaxies and QSOs 914 1. Helium 914 I. Int roduction and History 877 2. Mean metal abundance 915 II. Ob served Abundances 879 3. Abundance gradients in galaxies 915 A. The problem of the retrieval of meaningful data 879 III. Nuclear Processes, Their Sites and Products 917 1. D/H in molecules 879 A.
    [Show full text]