TITLE: GCN CIRCULAR NUMBER: 6544 SUBJECT: Swift XRT observations of the INTEGRAL burst GRB070615: Possible DATE: 07/06/16 20:55:10 GMT FROM: Olivier Godet at U.of Leicester O. Godet, N. Lyons, K.L. Page, P.A. Evans, J. Osborne, R. Starling (U. Leicester) and G. Tagliaferri (INAF-OAB) report on behalf the Swift-XRT team: The XRT started to observe the field of the INTEGRAL burst GRB 070615 (Mereghetti et al., GCN 6537) 10.7h after the IBAS trigger. We analysed around 3ks of PC data. A possible weak and uncatalogued X-ray source is detected at a position of: RA(J2000) = 02h 57m 15.37s Dec(J2000) = -04d 24' 26.6" with an uncertainty of 7.5 arcsec (90% containment radius). This is 23 arcsec from the INTEGRAL position given by Mereghetti et al. (GCN Circ. 6537). We note that there are only 5 counts detected in the error circle centred on this position. In this region, only ~0.07 background counts would be expected. Using the Bayesian method to find a 99.7\% level confidence limit on the actual number of counts from the source, the range would then be between 0.8 and 14.9 counts. We estimate the probability that this detection is due to a background fluctuation to be 6e-7, suggesting that this is a real detection. Since it is impossible to say whether or not the source is fading, we cannot say with any certainty that the source is the X-ray afterglow of GRB 070615. This circular is an official product of the Swift-XRT team.