TITLE: GCN CIRCULAR NUMBER: 6157 SUBJECT: GRB070227: possible X-ray afterglow detection DATE: 07/02/28 19:17:26 GMT FROM: Claudio Pagani at PSU/Swift-XRT C. Pagani, D. Grupe, D.N. Burrows (PSU) report on behalf of the Swift/XRT Team: The Swift BAT detected GRB 070227 at 22:21:59 UT (GCN 6156). The Swift observatory did not slew promptly because a planned slew terminated the trigger prematurely. The burst was found later in ground analysis. The XRT began taking data at 2007-02-28 13:51:31 UT, approximately 15 hours and 30 minutes after the trigger. In a preliminary data analysis of the first 2.6ks of PC data we detect an uncataloged X-ray source located at RA, Dec 120.5808 -46.3135 which is RA(J2000) = 08h 02m 19.4s Dec(J2000) = -46d 18' 48.7" We estimate an uncertainty of 8 arcseconds radius (90% containment). This position is 48 arcseconds from the BAT position (GCN 6156). The source count rate is approximately 0.005 counts/s. Observations are still underway and further ground analysis will be performed to determine if this X-ray source is fading. This circular is an official product of the Swift-XRT team.