[vsnet-grb-info 22699] GRB 190613A: Swift detection of a burst with an optical counterpart

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24798
SUBJECT: GRB 190613A: Swift detection of a burst with an optical counterpart
DATE:    19/06/13 04:18:46 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC),
J.D. Gropp (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), M. H. Siegel (PSU)
and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 04:07:18 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190613A (trigger=908288).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 182.559, +67.233 which is 
   RA(J2000) = 12h 10m 14s
   Dec(J2000) = +67d 13' 58"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
structure with a duration of about 30 sec.  The peak count rate
was ~500 counts/sec (15-350 keV), at ~10 sec after the trigger. 

The XRT began observing the field at 04:09:34.8 UT, 136.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 182.53286, 67.23489 which
is equivalent to:
   RA(J2000)  = 12h 10m 07.89s
   Dec(J2000) = +67d 14' 05.6"
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This
location is 37 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.  We
cannot determine whether the source is fading at the present time. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 2.5 s image was 1.18e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 144 seconds after the BAT trigger. There is a candidate afterglow in
the list of sources generated on-board at
  RA(J2000)  =	12:10:07.01 = 182.52919
  DEC(J2000) = +67:14:07.0  =  67.23528
with a 90%-confidence error radius of about 1.10 arc sec. This position is 9.9
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.28. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.02. 

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/)