Was the X-ray Afterglow of GRB 970815 Detected?
Abstract
GRB 970815 was a well-localized gamma-ray burst (GRB) detected by the All-Sky Monitor (ASM) on the Rossi X-Ray Timing Explorer (RXTE) for which no afterglow was identified despite follow-up ASCA and ROSAT pointings and optical imaging to limiting magnitude R > 23. While an X-ray source, AX/RX J1606.8+8130, was detected just outside the ASM error box, it was never associated with the GRB because it was not clearly fading and because no optical afterglow was ever discovered. We recently made deep optical observations of the AX/RX J1606.8+8130 position, which is blank to a limit of V > 24.3 and I > 24.0, implying an X-ray-to-optical flux ratio fX/fV > 500. In view of this extreme limit, we analyze and reevaluate the ASCA and ROSAT data and conclude that the X-ray source AX/RX J1606.8+8130 was indeed the afterglow of GRB 970815, which corresponds to an optically ``dark'' GRB. Alternatively, if AX/RX J1608+8130 is discovered to be a persistent source, then it could be associated with EGRET source 3EG J1621+8203, whose error box includes this position.
- Publication:
-
Gamma-Ray Bursts: 30 Years of Discovery
- Pub Date:
- September 2004
- DOI:
- 10.1063/1.1810902
- arXiv:
- arXiv:astro-ph/0312177
- Bibcode:
- 2004AIPC..727..533M
- Keywords:
-
- 98.70.Rz;
- 98.70.Qy;
- 95.80.+p;
- 07.87.+v;
- gamma-ray sources;
- gamma-ray bursts;
- X-ray sources;
- X-ray bursts;
- Astronomical catalogs atlases sky surveys databases retrieval systems archives etc.;
- Spaceborne and space research instruments apparatus and components;
- Astrophysics
- E-Print:
- 4 pages, 3 figures, to appear in the proceedings of the 2003 GRB Conference