TITLE: GCN CIRCULAR NUMBER: 36052 SUBJECT: Swift Trigger 1220736: detection of 4U 1543-62. DATE: 24/04/08 15:43:49 GMT FROM: K.L. Page at U Leicester <klp5@leicester.ac.uk> R. Brivio (INAF-OAB), S. Dichiara (PSU), M. Ferro (INAF-OAB), C. Gronwall (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII), A. Y. Lien (U Tampa), K. L. Page (U Leicester), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB) and B. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team: At 15:13:54 UT, the Swift Burst Alert Telescope (BAT) triggered on 4U 1543-62 (trigger=1220736). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 236.947, -62.534 which is RA(J2000) = 15h 47m 47s Dec(J2000) = -62d 32' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 10 sec. The peak count rate was ~300 counts/sec (15-350 keV), at ~4 sec after the trigger. The XRT began observing the field at 15:16:08.0 UT, 133.4 seconds after the BAT trigger. XRT found a bright X-ray source located at RA, Dec 236.9760, -62.5656 which is equivalent to: RA(J2000) = 15h 47m 54.24s Dec(J2000) = -62d 33' 56.2" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 123 arcseconds from the BAT onboard position, within the BAT error circle. This position is 7.6 arcseconds from the known source 4U 1543-62. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 5.62e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 141 seconds after the BAT trigger. A source consistent with the location of 4U 1543-62 is detected. This source is a known Low Mass X-ray Binary, also known by the name QU TrA. View this GCN Circular online at https://gcn.nasa.gov/circulars/36052. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...