Prompt optical detection of GRB 050401 with ROTSE-IIIa

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Rykoff E., Yost S., Krimm H., Aharonian F., Akerlof C., Alatalo K., ...More

ASTROPHYSICAL JOURNAL, vol.631, no.2, 2005 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 631 Issue: 2
  • Publication Date: 2005
  • Doi Number: 10.1086/497370
  • Journal Name: ASTROPHYSICAL JOURNAL
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Middle East Technical University Affiliated: No

Abstract

The ROTSE-IIIa telescope at Siding Spring Observatory, Australia, detected prompt optical emission from Swift GRB 050401. We present observations of the early optical afterglow, first detected by the ROTSE-IIIa telescope 33 s after the start of gamma-ray emission, contemporaneous with the brightest peak of this emission. This GRB was neither exceptionally long nor bright. This is the first prompt optical detection of a GRB of typical duration and luminosity. We find that the early afterglow decay does not deviate significantly from the power-law decay observable at later times and is uncorrelated with the prompt gamma-ray emission. We compare this detection with the other two GRBs with prompt observations, GRB 990123 and GRB 041219a. All three bursts exhibit quite different behavior at early times.