NASA Swift: GRB 060512: Swift detection of a burst with an optical afterglow

TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 5117
SUBJECT: GRB 060512: Swift detection of a burst with an optical afterglow
DATE: 06/05/12 23:57:25 GMT
FROM: Jay R. Cummings at NASA/GSFC/Swift

J. R. Cummings (NASA/ORAU), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), H. A. Krimm (GSFC/USRA), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. Stamatikos (NASA/GSFC/ORAU) report on behalf of the Swift Team:

At 23:13:20 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060512 (trigger=209755). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 195.772, +41.212 {13h 03m 05s, +41d 12′ 43″} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak with a duration of about 20 sec. The peak count rate was ~500 counts/sec (15-350 keV), at ~3 sec after the trigger.

The XRT began observing the field at 23:15:02 UT, 102 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA(J2000) = 13h 03m 05.8s, Dec(J2000) = +41d 11′ 30.4″, with an estimated uncertainty of 7.6 arcseconds (90% confidence radius). This location is 73 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 2.6e-10 erg/cm2/s (0.2-10 keV).

UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 112 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7’x2.7′ sub-image at (RA,DEC) (J2000) of (195.7742,41.1909) or (13h03m05.81s,+41o11’27.2″) with a 1-sigma error radius of about 0.5 arc sec. This position is 3.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 16.2 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02.