TITLE:   GCN CIRCULAR
NUMBER:  24888
SUBJECT: GRB 190627A: Swift detection of a burst
DATE:    19/06/27 11:48:34 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU), J.D. Gropp (PSU),
H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester),
M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 11:18:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190627A (trigger=911609).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 244.830, -5.292, which is 
   RA(J2000)  =  16h 19m 19s
   Dec(J2000) = -05d 17' 31"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a couple of peaks
with a total duration of about 10 sec.  The peak count rate
was ~1200 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 11:20:20.8 UT, 109.8 seconds after
the BAT trigger. The initial XRT centroid was caused by a cosmic ray, and 
is therefore unrelated to the trigger. While no significant X-ray source 
was then detected in 20 s of promptly-downlinked data, there is a small 
number of X-ray photons at the same location as the tentative UVOT source. 

UVOT took a finding chart exposure of  29 seconds with the White filter
starting 114 seconds after the BAT trigger. The 2.7'x2.7' sub-image is
unavailable at this time. The list of sources generated on board shows a
possible new source at a location of:

  RA(J2000)  =  16:19:18.80 = 244.8283
  DEC(J2000) = -05:17:23.2  =  -5.2898

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 0.18. 

Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.com). 
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/)