TITLE: GCN CIRCULAR NUMBER: 19548 SUBJECT: BAT trigger 700791 (possible GRB 160622A) is SNR RCW 103 DATE: 16/06/22 14:20:36 GMT FROM: Phil Evans at U of Leicester A. D'Ai(INAF-IASFPA), P.Evans (U. Leicester), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), A. Maselli (INAF-IASFPA), T. Sakamoto (AGU) and M. H. Siegel (PSU) report on behalf of the Swift Team: Swift has gathered 5.8 ks of WT mode data and 463 s of PC mode data on the field of the BAT trigger 700791 (= possible GRB 160622A, GCN 19547). The XRT image is dominated by diffuse emission from the supernova remnant RCW 103 (Frank et al., ApJ, 2015, 810,113), with a bright central source at RA,Dec. = 244.40282, -51.03916, which is equivalent to: RA (J2000.0) = 16h 17m 36.68s Dec (J2000.0) = -51d 02' 21.0" with an uncertainty of 3.5" (radius, 90% confidence). This is consistent with the catalogued X-ray source 3XMM J161736.1-510224. Analysis is complicated by the presence of the diffuse emission from the SNR, however the source count rate is ~2 ct/sec, with a flux of approximately 9.1 (+2.0, -1.6) × 10^-11 erg cm^-2 s^-1 (derived from a power-law spectrum with NH=7.0 (+3.6, -2.5)e21 cm^-2, and a photon index of 2.2 (+/- 0.4). This is substantially above the 3XMM count rate of 2.567 (+/- 0.020)e-12 erg cm^-2 s^-1. Observations and analysis are ongoing. This circular is an official product of the Swift XRT team. [GCN OPS NOTE(22jun16): Per author's request, A.D'A's name was corrected, and the missing minus sign for the sexagesimal form of the Dec value was added.]