TITLE: GCN CIRCULAR NUMBER: 7564 SUBJECT: GRB 080405: Mars Oddysey and Swift-BAT detection, possible host galaxy DATE: 08/04/06 04:59:33 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (NASA/GSFC/UMBC) on behalf of the Swift-BAT team K. Hurley on behalf of the Mars Odyssey GRS team At 09:18:55.6 UTC on April 5, 2008, BAT triggered on GRB 080405 (trigger #308549). Automated attempts onboard to find a significant source in an image were prematurely terminated by a Swift preplanned slew manuver. Mars Oddyssey GRS detected a ~10 s long event at 33236 s Mars time (09:13:56 +/- 700 s Earth time), and the team informed the IPN. The BAT team searched the BAT data for a corresponding event and found the failed onboard trigger and a large peak in the count rates. Ground analysis of BAT data found a strong source at RA, Dec 162.597, -4.250, which is: 10h 50m 23.3s, -4d 15' 00" (J2000), 2.0 arcmin error radius (estimated 90% confidence). This is 0.4 arcmin from [BTW2002] J105021.50-041505.9, the host galaxy of 2002AL (see Becker et al. IAUC #7804). The BAT light curve shows a slow-rise and slow-decay Gaussian-like envelope with multiple peaks. T90 is approximately 40 +- 5 seconds. The peak countrate was about 9000 counts/sec at T+25 sec (15-350 keV). The source was 37% coded in the BAT field of view. Because the burst was not detected onboard, the full burst response was not collected. Partial BAT data products will be available. Swift will execute a TOO on April 6 for the narrow-field instruments to observe this burst.