TITLE: GCN CIRCULAR NUMBER: 7762 SUBJECT: GRB 080515: Swift-XRT position and analysis DATE: 08/05/22 13:58:50 GMT FROM: Kim Page at U.of Leicester K.L. Page, A.P. Beardmore (U. Leicester) and S.T. Holland (CRESST/USRA/GSFC) report on behalf of the Swift-XRT and UVOT teams: A follow-up observation of GRB 080515 was performed about 1.5 days after the initial trigger (Holland et al., GCN Circ. 7721), when the burst was no longer Sun-constrained. An X-ray source was identified within the BAT ground-calculated error circle (Fenimore et al., GCN Circ. 7726). A further observation, 3.5 days later, confirmed that the source is fading, with alpha = 1.0 +0.7/-0.5. We therefore believe this is the X-ray afterglow of the GRB. The position of this source is RA, Dec = 3.16343, 32.57894, which is equivalent to: RA(J2000) = 00 12 39.22 Dec(J2000) = +32 34 44.2 with an uncertainty of 3.8 arcsec (radius, 90% containment). This is 54 arcsec from the BAT position given by Fenimore et al. in GCN Circ. 7726. A spectrum of the source can be fitted with a power-law of Gamma = 1.95 +/- 0.34, absorbed by the Galactic column of 4.65x10^20 cm^-2. This spectrum, averaged over 1.5-6.6 days after the burst, has an observed (unabsorbed) flux of 2.28x10^-13 (2.59x10^-13) erg cm^-2 s^-1. The field was observed by UVOT with the v filter for 6262 s between ~1.5 and 2.4 days after the BAT trigger. The XRT error circle is located in the scattered light halo of the B = 11.4 star TYC 2264-1051-1, so it is not possible to constrain the presence of an afterglow in the UVOT data. This circular is an official product of the Swift-XRT and UVOT teams.