GRB 190613B: Swift detection of a burst with an optical counterpart
Abstract
At 10:47:02 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190613B (trigger=908329). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 305.422, -4.664 which is RA(J2000) = 20h 21m 41s Dec(J2000) = -04d 39' 49" 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 15 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 10:48:39.5 UT, 97.5 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 305.4294, -4.6461 which is equivalent to: RA(J2000) = 20h 21m 43.06s Dec(J2000) = -04d 38' 46.0" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 69 arcseconds from the BAT onboard position, within the BAT error circle. 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 4.90e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 105 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 20:21:43.65 = 305.43189 DEC(J2000) = -04:38:47.9 = -4.64665 with a 90%-confidence error radius of about 0.62 arc sec. This position is 9.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.76 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07. Burst Advocate for this burst is A. D'Ai (antonino.dai 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:
- June 2019
- Bibcode:
- 2019GCN.24807....1D