GCN Circular 5163

S. Campana (INAF-OAB), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
N. Gehrels (NASA/GSFC), C. Guidorzi (Univ Bicocca&INAF-OAB),
J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
K. M. McLean (LANL/UTD), A. Moretti (INAF-OAB),
M. Stamatikos (NASA/ORAU), G. Tagliaferri (INAF-OAB) and
D. E. Vanden Berk (PSU) report on behalf of the Swift Team:

Following up the report of the Swift GRB (Campana, et al., GCN 5162
Not found
 
 
),
we note that the BAT lightcurve shows a well separated second period
of emission starting at ~T+220 sec and lasting until ~T+270 sec. 
The shape of the emission is FRED-like.  Based on the 4-band TDRSS
lightcurve, this second emission is significantly softer that the 
original emission at T+0. 

Based on initial data we find a refined XRT position of 
RA(J2000): 15 31 18.27, DEC(J2000): +00 17 07.6, with an error 
radius of 4.3 arcsec (90% confidence) and 3 arcsec from the previously 
reported UVOT candidate position. The XRT light curve shows a sharp 
increase in the count rate starting around T+220 s from burst trigger, 
approximately coincident with the second BAT peak. 

As shown in the table below, UVOT sees a fading afterglow in 
the four finding chart exposures for this burst. In the table,
T is the time in seconds since the BAT trigger at the start 
of the exposure. 

  T  Exposure Filter  Magnitude
  83  100     White    17.6
 188  400     V        17.2
 866  400     V        17.8
1274  100     White    18.4

We note that the location of this burst is ~11.3 hours from the Sun
and therefore well suited for ground-based follow-ups. 
There is no bright galaxy at this location in the archived SDSS images. 
We will start receiving the full downlinked data set around 18:00 UT.