[vsnet-grb-info 4501] GRB 070412: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6273
SUBJECT: GRB 070412: Swift detection of a burst
DATE:    07/04/12 01:58:32 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

P. Romano (Univ. Bicocca & INAF-OAB), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC),
N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/GSFC/USRA),
H. A. Krimm (GSFC/USRA), A. Moretti (INAF-OAB), C. Pagani (PSU),
D. M. Palmer (LANL), T. Sakamoto (NASA/ORAU),
M. Stamatikos (NASA/ORAU) and D. E. Vanden Berk (PSU) report on
behalf of the Swift Team:

At 01:27:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070412 (trigger=275119).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 181.505, +40.101 which is 
   RA(J2000) = 12h 06m 01s
   Dec(J2000) = +40d 06' 03"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a double-peaked
structure with peaks at approximately 5 and 30 seconds and a total
duration of about 40 sec.  The peak count rate
was ~2400 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 01:28:04 UT, 61 seconds after the
BAT trigger. Analysis of XRT downlinked data found an X-ray source
located at RA, Dec 181.54,   +40.141 which is
   RA(J2000)  =  12h 06m 10.5s  
   Dec(J2000) =  40d 08' 27.8"
with an uncertainty of 5.6 arcseconds (radius, 90% containment). 
This location is 181 arcseconds from the BAT on-board position,
outside the BAT error circle. The initial flux in the 2.5s image
was 7.0e-10 erg/cm2/s (0.2-10 keV). 

UVOT took a finding chart exposure of  54 seconds with the White (160-650 nm)
filter starting 70 seconds after the BAT trigger. No afterglow candidate has
been found in the initial data products. Image catalog data are not available
at this time. 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 extinction of E(B-V)=0.02. 

The TDRSS transmissions were delayed by 11 minutes due to the trigger
occuring during a Malindi downlink.