GCN Circular 37896

A. Melandri (INAF-OAR), V. D'Elia (SSDC & INAF-OAR),
D. M. Palmer (LANL), T. Sakamoto (AGU) and B. Sbarufatti (INAF-OAB)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 22:42:32 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 241026A (trigger=1262764).  Swift slewed immediately to the burst.
The BAT on-board calculated location is 
RA, Dec 293.423, +57.980 which is 
   RA(J2000) = 19h 33m 42s
   Dec(J2000) = +57d 58' 49"
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 ~3600 counts/sec (15-350 keV), at ~0 sec after the trigger.

The XRT began observing the field at 22:44:26.4 UT, 114.5 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 293.39935, 57.98544 which is equivalent
to:
   RA(J2000)  = 19h 33m 35.84s
   Dec(J2000) = +57d 59' 07.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 49 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 https://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (8.92 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.4
(+3.14/-2.68) x 10^21 cm^-2 (90% confidence).

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 117 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Data from the 2.7'x2.7' sub-image are
not available at this time. 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 0.073.

Burst Advocate for this burst is A. Melandri (andrea.melandri 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/)