GRB 190719C: Swift detection of a burst
Abstract
At 14:58:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190719C (trigger=915381). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 240.210, +12.977 which is RA(J2000) = 16h 00m 50s Dec(J2000) = +12d 58' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a total duration of about 100 sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 14:59:35.3 UT, 60.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 240.20700, 12.99995 which is equivalent to: RA(J2000) = 16h 00m 49.68s Dec(J2000) = +12d 59' 59.8" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 83 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (4.69 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9 (+3.40/-2.88) x 10^21 cm^-2 (90% confidence). The initial flux in the 0.1 s image was 1.69e-08 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 71 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.04. The Fermi GBM team announced the detection of GRB 190719C (GCN Circ 25104). Given the temporal coincidence, it is likely that this is the same burst. Burst Advocate for this burst is E. Ambrosi (elena.ambrosi AT inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
- Publication:
-
GRB Coordinates Network
- Pub Date:
- July 2019
- Bibcode:
- 2019GCN.25106....1A