GCN Circular 3027

K. Page (U. Leicester), G. Tagliaferri, S. Campana, A. Moretti, C. 
Pagani,  P. Romano, G.
Chincarini (OAB), G. Cusumano, V. Mangano, V. La Parola (IASF/Palermo), D. 
N. Burrows, J. Kennea, J. E. Hill, J. A. Nousek (PSU), J. P. Osborne, M. 
Goad, A. Beardmore, A. F. Abbey, A. A. Wells (U. Leicester), P. Giommi, M. 
Capalbi, M. Perri, F. Tamburelli (ASDC), T. Sakamoto, L. Angelini, N. 
Gehrels (GSFC), W. Voges (MPE), L. Cominsky (Sonoma State U.), M. Tripicco 
(GSFC-SSAI), report on behalf of the Swift XRT team:

The Swift BAT instrument detected GRB 050215b at 02:35:00 UT on 15 Feb 2005.
The observatory executed an automated slew to the BAT position, but the XRT 
was in Manual State collecting calibration data and did not perform its 
normal automated GRB observing sequence.  Furthermore, the satellite 
entered the SAA shortly after detecting this burst, and the XRT had data 
collection disabled until it exited the SAA at 03:03 to 03:10 UT, at which 
time the XRT was in Manual state and made observations in Windowed Timing 
(WT) mode.  On the second orbit XRT collected data from 04:11 to 04:15 in 
Photon Counting (PC) mode, and from 04:44 to 04:47 in WT mode.  (In between 
Swift was again located in the SAA).  Observations continued in both WT and 
PC modes on subsequent orbits.  With three orbits of PC mode data processed 
through the ground software, we find a faint, uncataloged X-ray source 
located 35 arcseconds from the BAT position at

RA(J2000) = 11 37 46.1, Dec(J2000) = +40 47 54.3.

The XRT alignment calibration is still in progress.  We estimate a systematic
uncertainty in this position of 6 arc seconds radius.

However, the lightcurve of this source, in both WT and PC mode, does NOT 
appear to be fading, although the source is extremely weak and the 
statistics are not good enough yet for an accurate 
determination.  GRB050215b remains the Swift Automated Target, and we 
expect to continue monitoring operations for the next 12 hours.