STRUCTURE FUNCTION ANALYSIS OF LONG-TERM QUASAR VARIABILITY Metadata

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Title

  • Main Title STRUCTURE FUNCTION ANALYSIS OF LONG-TERM QUASAR VARIABILITY

Creator

  • Author: de Vries, W
    Creator Type: Personal
  • Author: Becker, R
    Creator Type: Personal
  • Author: White, R
    Creator Type: Personal
  • Author: Loomis, C
    Creator Type: Personal

Contributor

  • Sponsor: United States. Department of Energy.
    Contributor Type: Organization
    Contributor Info: US Department of Energy (United States)

Publisher

  • Name: Lawrence Livermore National Laboratory
    Place of Publication: Livermore, California
    Additional Info: Lawrence Livermore National Lab., Livermore, CA (United States)

Date

  • Creation: 2004-11-15

Language

  • English

Description

  • Content Description: In our second paper on long-term quasar variability, we employ a much larger database of quasars than in de Vries, Becker & White. This expanded sample, containing 35,165 quasars from the Sloan Digital Sky Survey Data Release 2, and 6,413 additional quasars in the same area of the sky taken from the 2dF QSO Redshift Survey, allows us to significantly improve on our earlier conclusions. As before, all the historic quasar photometry has been calibrated onto the SDSS scale by using large numbers of calibration stars around each quasar position. We find the following: (1) the outbursts have an asymmetric light-curve profile, with a fast-rise, slow-decline shape; this argues against a scenario in which micro-lensing events along the line-of-sight to the quasars are dominating the long-term variations in quasars; (2) there is no turnover in the Structure Function of the quasars up to time-scales of {approx}40 years, and the increase in variability with increasing time-lags is monotonic and constant; and consequently, (3) there is not a single preferred characteristic outburst time-scale for the quasars, but most likely a continuum of outburst time-scales, (4) the magnitude of the quasar variability is a function of wavelength: variability increases toward the blue part of the spectrum, (5) high-luminosity quasars vary less than low-luminosity quasars, consistent with a scenario in which variations have limited absolute magnitude. Based on this, we conclude that quasar variability is intrinsic to the Active Galactic Nucleus, is caused by chromatic outbursts/flares with a limited luminosity range and varying time-scales, and which have an overall asymmetric light-curve shape. Currently the model that has the most promise of fitting the observations is based on accretion disk instabilities.
  • Physical Description: page(s) pp. 615; PDF-FILE: 18 ; SIZE: 1.1 MBYTES

Subject

  • Keyword: Calibration
  • STI Subject Categories: 99 General And Miscellaneous//Mathematics, Computing, And Information Science
  • Keyword: Quasars
  • Keyword: Luminosity
  • Keyword: Sky
  • Keyword: Accretion Disks
  • Keyword: Shape
  • Keyword: Stars
  • STI Subject Categories: 71 Classical And Quantum Mechanics, General Physics
  • Keyword: Structure Functions
  • Keyword: Photometry

Source

  • Journal Name: Astronomical Journal; Journal Volume: 129; Journal Issue: 2; Other Information: Journal published February 1, 2005

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Article

Format

  • Text

Identifier

  • Report No.: UCRL-JRNL-208117
  • Grant Number: W-7405-ENG-48
  • Office of Scientific & Technical Information Report Number: 15011538
  • Archival Resource Key: ark:/67531/metadc1410080