TITLE:   GCN CIRCULAR
NUMBER:  14752
SUBJECT: GRB 130604A: Swift detection of a burst
DATE:    13/06/04 07:08:43 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), C. Gronwall (PSU),
C. B. Markwardt (NASA/GSFC), C. Pagani (U Leicester),
D. M. Palmer (LANL), M. H. Siegel (PSU) and
R. L. C. Starling (U Leicester) report on behalf of the Swift Team:

At 06:54:26 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130604A (trigger=557354).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 250.080, +68.210 which is 
   RA(J2000) = 16h 40m 19s
   Dec(J2000) = +68d 12' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
FRED-like structure with a duration of about 70 sec.  The peak count 
rate was ~1500 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 06:56:06.2 UT, 99.3 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 250.1889,
68.2260 which is equivalent to:
   RA(J2000)  = 16h 40m 45.34s
   Dec(J2000) = +68d 13' 33.6"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 156 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 4.70
x 10^20 cm^-2 (Kalberla et al. 2005). 

The initial flux in the 2.5 s image was 1.76e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT data are not available at this time. Analysis is awaiting the full
data set. 

Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.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/too.html.)