Astronomy Letters

, Volume 33, Issue 12, pp 789–796

Cosmic GRB 060428C detected in the field of view of the IBIS and SPI telescopes onboard the INTEGRAL observatory and its early afterglow

Article

DOI: 10.1134/S1063773707120018

Cite this article as:
Grebenev, S.A. & Chelovekov, I.V. Astron. Lett. (2007) 33: 789. doi:10.1134/S1063773707120018

Abstract

While analyzing the archival data of the INTEGRAL observatory, we detected and localized a cosmic gamma-ray burst recorded on April 28, 2006, by the IBIS/ISGRI and SPI telescopes in their fields of view. Since the burst was not revealed by the INTEGRAL burst alert system (IBAS), information about its coordinates was not distributed in time and no search for its afterglow was conducted. The burst was recorded by the KONUS/WIND and RHES SI satellites. Its 20–200-keV fluence was 2.3 × 10−6 erg cm−2, the peak flux was 3.6 × 10−7 erg cm−2 s−1 (3.9 phot. cm−2 s−1). The burst had a complex multipeaked profile and stood out among typical bursts by an increase in its hardness with time. At the flux peak, the spectrum was characterized by a photon index α ≃ −1.5 and a peak energy Ep ≃ 95 keV. The burst lasted for ∼12 s, after which its afterglow decaying as a power law with an index γ ∼ −4.5 was observed at energies 15–45 keV. The spectral hardness decreased noticeably during the afterglow.

Key words

gamma-ray sources cosmic gamma-ray bursts 

PACS numbers

95.85.Nv 95.85.Pw 98.70.Rz 

Copyright information

© Pleiades Publishing, Inc. 2007

Authors and Affiliations

  1. 1.Space Research InstituteRussian Academy of SciencesMoscowRussia

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