[vsnet-grb-info 14768] GRB 140408A: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16082
SUBJECT: GRB 140408A: Swift detection of a burst
DATE:    14/04/08 13:35:46 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at milkyway.gsfc.nasa.gov>

V. D'Elia (ASDC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC),
S. T. Holland (STScI), L. Izzo (URoma/ICRA), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU),
R. L. C. Starling (U Leicester) and C. A. Swenson (PSU) report on
behalf of the Swift Team:

At 13:15:54 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140408A (trigger=595141).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 290.685, -12.578 which is 
   RA(J2000)  =  19h 22m 44s
   Dec(J2000) = -12d 34' 40"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
with a duration of about 10 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 13:17:40.2 UT, 105.5 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 290.71576, -12.59373 which is
equivalent to:
   RA(J2000)  = 19h 22m 51.78s
   Dec(J2000) = -12d 35' 37.4"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 122 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. 

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 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. Because of the density of catalogued stars,  further
analysis is required to report an upper limit for any afterglow in the
region. No correction has been made for the expected extinction
corresponding  to E(B-V) of 0.19. 

Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.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/too.html.)