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GCN Circular 24993

Subject
GRB 190706B: Swift detection of a burst
Date
2019-07-06T12:53:10Z (5 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
A. Tohuvavohu (PSU), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (PSU)
and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 12:40:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190706B (trigger=913302).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 107.449, -29.584, which is 
   RA(J2000)  =  07h 09m 48s
   Dec(J2000) = -29d 35' 02"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a few peaks
with a total duration of about 25 sec.  The peak count rate
was ~1100 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 12:42:24.4 UT, 94.4 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 107.46161, -29.55341 which is
equivalent to:
   RA(J2000)  = 07h 09m 50.79s
   Dec(J2000) = -29d 33' 12.3"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 116 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. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.40
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 100 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 none of
the XRT error circle. 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 0.15. 

Burst Advocate for this burst is A. Tohuvavohu (aaronb AT swift.psu.edu). 
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/)
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