NASA Swift: GRB 060428B: Swift detection of a burst
TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 5017
SUBJECT: GRB 060428B: Swift detection of a burst
DATE: 06/04/28 09:31:30 GMT
FROM: Scott Barthelmy at NASA/GSFC Scott@lheamail.gsfc.nasa.gov
S. Campana (INAF-OAB), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. R. Cummings (NASA/ORAU), N. Gehrels (NASA/GSFC), C. B. Markwardt (GSFC/UMD), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-OAB) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team:
At 08:54:38 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060428B (trigger=207399). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 235.350,+62.010 {15h 41m 24s,+62d 00′ 36″} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). This is an image trigger (128 sec), so the lightcurve does not show any significant activity (as is typical).
The XRT began observing the field at 08:58:02 UT, 204 seconds after the BAT trigger. XRT found a bright, fading X-ray source located at RA(J2000) = 15h 41m 25.6s, Dec(J2000) = +62d 01′ 25.6″, with an estimated uncertainty of 5.0 arcseconds (90% confidence radius). This location is 51 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 2.3e-09 erg/cm2/s (0.2-10 keV).
UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 212 seconds after the BAT trigger, and of 400 sec. with the V filter starting at 965 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7’x2.7′ sub-image covers 100% of the XRT error circle. The 3-sigma V band upper limit is about 19.1 mag. The 8’x8′ region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.
