TITLE: GCN CIRCULAR NUMBER: 9847 SUBJECT: GRB 090827: Swift XRT and UVOT observations DATE: 09/08/29 09:38:48 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) and S.R. Oates (MSSL-UCL) report on behalf of the Swift team: The Swift-XRT observed the field of GRB 090827 (Cummings et al. GCN Circ. 9846), gathering 7.1 ks of Photon Counting (PC) mode data from T0+92 ks to T0+122 ks. Inside the BAT error circle we find a single, uncatalogued source at a location of RA,Dec = 18.4495, -50.8957 which is equivalent to: RA (J2000) = 01h 13m 47.88s Dec (J2000) = -50d 53' 44.0" with an uncertainty of 6.4 arcsec (radius, 90% condfidence). There are only 14 counts detected from this source, giving it a count rate of (3+/-1) x 10^-3 ct/sec. It is impossible to say whether this source is fading. A spectrum formed from all available data can be well fitted using an absorbed power law, with a photon index of 1.6 (+0.9, -0.8) and an absorption column density consistent with the Galactic value of 1.6 x 10^20 cm^-2 (Kalberla et al. 2005). The Swift-UVOT began settled observations of the field 91.6 ks after the BAT trigger. We do not detect any source at the XRT position. The 3-sigma upper limits for the finding chart exposure is: Filter T_start(s) T_stop(s) Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------------- U 91644 120333 5671 > 21.94 ------------------------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight of E_(B-V) = 0.01 mag. All photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627). This circular is an official product of the Swift team.