[vsnet-grb-info 21803] GRB 190219A: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23902
SUBJECT: GRB 190219A: Swift detection of a burst
DATE:    19/02/19 19:53:25 GMT
FROM:    Kim Page at U.of Leicester  <klp5 at leicester.ac.uk>

A. P. Beardmore (U Leicester), J. A. Kennea (PSU),
N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), M. J. Moss (George Washington University),
K. L. Page (U Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 19:38:58 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190219A (trigger=889748).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 189.757, +76.614 which is 
   RA(J2000) = 12h 39m 02s
   Dec(J2000) = +76d 36' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 100 sec.  The peak count rate
was ~1300 counts/sec (15-350 keV), at ~70 sec after the trigger. 

The XRT began observing the field at 19:40:38.9 UT, 100.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 189.62442,
76.61186 which is equivalent to:
   RA(J2000)  = 12h 38m 29.86s
   Dec(J2000) = +76d 36' 42.7"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 110 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. No spectrum from the promptly downlinked
event data is yet available to determine the column density. 

The initial flux in the 0.1 s image was 1.38e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 109 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 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
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
0.03. 

Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 
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/)