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From the same journal

Fermi/gamma-ray burst monitor observations of SGR J0501+4516 bursts

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  • 905869

    Accepted author manuscript, 1 MB, PDF document

  • Lin Lin
  • Chryssa Kouveliotou
  • Matthew G. Baring
  • Alexander J. van der Horst
  • Sylvain Guiriec
  • Peter M. Woods
  • Ersin Gogus
  • Yuki Kaneko
  • Jeffrey Scargle
  • Jonathan Granot
  • Robert Preece
  • Andreas von Kienlin
  • Vandiver Chaplin
  • Anna L. Watts
  • Ralph A. M. J. Wijers
  • Shuang Nan Zhang
  • Narayan Bhat
  • Mark H. Finger
  • Neil Gehrels
  • Alice Harding
  • And 10 others
  • Lex Kaper
  • Victoria Kaspi
  • Julie Mcenery
  • Charles A. Meegan
  • William S. Paciesas
  • Asaf Pe'er
  • Enrico Ramirez-Ruiz
  • Michiel van der Klis
  • Stefanie Wachter
  • Colleen Wilson-Hodge
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Original languageEnglish
Article number87
Number of pages16
Pages (from-to)-
JournalThe Astrophysical Journal
Journal publication date1 Oct 2011
Volume739
Issue2
DOIs
Publication statusPublished - 1 Oct 2011

Abstract

We present our temporal and spectral analyses of 29 bursts from SGR J0501+4516, detected with the gamma-ray burst monitor on board the Fermi Gamma-ray Space Telescope during 13 days of the source's activation in 2008 (August 22-September 3). We find that the T-90 durations of the bursts can be fit with a log-normal distribution with a mean value of similar to 123 ms. We also estimate for the first time event durations of soft gamma repeater (SGR) bursts in photon space (i.e., using their deconvolved spectra) and find that these are very similar to the T-90 values estimated in count space (following a log-normal distribution with a mean value of similar to 124 ms). We fit the time-integrated spectra for each burst and the time-resolved spectra of the five brightest bursts with several models. We find that a single power law with an exponential cutoff model fits all 29 bursts well, while 18 of the events can also be fit with two blackbody functions. We expand on the physical interpretation of these two models and we compare their parameters and discuss their evolution. We show that the time-integrated and time-resolved spectra reveal that E-peak decreases with energy flux (and fluence) to a minimum of similar to 30 keV at F = 8.7 x 10(-6) erg cm(-2) s(-1), increasing steadily afterward. Two more sources exhibit a similar trend: SGRs J1550-5418 and 1806-20. The isotropic luminosity, L-iso, corresponding to these flux values is roughly similar for all sources (0.4-1.5 x 10(40) erg s(-1)).

Notes

‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical Society

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