TITLE: GCN CIRCULAR NUMBER: 35861 SUBJECT: Swift J151857.0-572147: Swift-BAT refined analysis DATE: 24/03/04 18:35:02 GMT FROM: Amy <yarleen@gmail.com> S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of Swift J151857.0-572147 (trigger #1218452) (Lien et al., GCN Circ. 35849). The BAT ground-calculated position is RA, Dec = 229.773, -57.364 deg which is RA(J2000) = 15h 19m 05.5s Dec(J2000) = -57d 21' 50.8" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 86%. The mask-weighted light curve shows a consistent emission throughout the entire time interval when the source was in the BAT FOV from T-127 s to T+798 s. In addition, BAT triggered on this source again on March 4th at 08:53 UT (Ambrosi et al., GCN Circ. #35858), indicating that the source is still detectable in BAT. The BAT transient monitor shows that the source started to appear on March 3rd. The time-averaged spectrum from T-83.64 to T+753.64 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.72 +- 0.44, and Epeak of 14.0 +- 10.1 keV (chi squared 72.90 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.7 +- 0.4 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T-80.60 sec in the 15-150 keV band is 0.4 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.48 +- 0.11 (chi squared 79.64 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1218452 The BAT transient monitor page for this source will be available at https://swift.gsfc.nasa.gov/results/transients/weak/SwiftJ1518-5721/ View this GCN Circular online at https://gcn.nasa.gov/circulars/35861. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...