GRB follow-up team

GRB 050509b

On May 5, 2006 we participated in identification of the short GRB 050509b detected by the SWIFT observatory. An area of the burst localization was investigated with the BTA down to 26 st. magn. The host galaxy of GRB 050509b is most probably an elliptic galaxy with z = 0.225 which is neighbor to the localization area. Thus, our group participated in the very first identifications of short ( < 2 s ) GRBs.

GRB050509b is the first GRB identified in optical (with elliptical galaxy) in Summer 2005.

The paper is published in A &A, 439 (2005), L15-L18.

Deep R image of a field of the short GRB 050509b taken with the 6-meter telescope on May 11, 2005. Contribution of the elliptical galaxy denoted by a cross was subtracted to show better a content of the SwiftXRT error box (down). 6 sources S1-S6 are shown within the box. The field is 45"x20"

Fitting of a synthetic spectrum to a wide-band BRIJHK spectrum of the supposed host galaxy of the gamma-ray burst denoted by a cross in the first figure. The best fittings of spectral energy distribution (SED) are acheived for elliptic galaxies of age of ~250 Myr. In SED fitting the Salpeter IMF (initial stellar mass distribution function) (1955) and the absorption law]by Calzetti et al. (2000) were supposed.

The observational results were obtained under a joint porgram of Instituto de Astrofisica de Andalucia (Alberto J. Castro-Tirado, IAA-CSIC, Spain) and SAO RAS