GCN Circular 3374
C. Hurkett, K.Page, J. P. Osborne (U Leicester), B. Zhang (UNLV), J. Kennea, D. N. Burrows (PSU) and N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT team: The Swift XRT observed the INTEGRAL burst GRB 050502a for ~2.5ks from 13:17 UT to 18:42 UT on 02 May 2005; for ~2.5 ks from 15:00 UT to 20:01 UT on 03 May 2005 and for ~43 ks from 00:28 on 04 May 2005 to 23:10 on 05 May 2005. In the first observation (02 May 2005) we detect no source in a 20 arcsec radius circle centred at the position of the optical counterpart identified by Yost et al 2005 (GCN 3322), with a 90% confidence upper limit of 1.03e-3 counts/s (0.2 - 10.0 keV). Combining data from all three observations, we obtain 35.5 ks of good data after normal data screening. We still detect no source in a 20 arcsec radius circle centred at this position, with a 90% confidence upper limit of 1.8e-4 counts/s (0.2 - 10.0 keV). Assuming a Crab-like spectrum, this corresponds to 7e-15 ergs/cm2/s (0.5 - 10.0 keV). Compared to other Swift XRT afterglows, GRB 050502a is unusually faint at these times.