Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 6375

GRB 070506: Swift detection of a burst with optical afterglow
2007-05-06T06:05:32Z (17 years ago)
David Palmer at LANL <>
C. Pagani (PSU), M. M. Chester (PSU),
C. Guidorzi (Univ Bicocca&INAF-OAB), S. Immler (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), J. L. Racusin (PSU),
T. Sakamoto (NASA/ORAU), M. Stamatikos (NASA/ORAU) and L. Vetere (PSU)
report on behalf of the Swift Team:

At 05:35:58 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070506 (trigger=278693).  Swift slewed to the burst
immediately after the end of the 64 second image trigger. 
The BAT on-board calculated location is RA, Dec 347.217, +10.728 which is 
   RA(J2000) = 23h 08m 52s
   Dec(J2000) = +10d 43' 42"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a double-peaked
structure with a duration of about 6 sec.  The peak count rate
was ~1700 counts/sec (15-350 keV), at ~6 sec after the trigger. 

The XRT began observing the field at 05:38:05 UT, 127 seconds after
the BAT trigger. Using ground-processed quick-look data, XRT found an
uncatalogued X-ray source located at RA, Dec 347.2192, +10.7224 which
   RA(J2000) = 23h 08m 52.6s
   Dec(J2000) = 10d 43' 20.7" 
with an uncertainty of 9.0 arcseconds (radius, 90% containment). This
location is 22 arcseconds from the BAT on-board position, within the
BAT error circle. The initial flux in the 2.5s image was 2.5e-10
erg/cm2/s (0.2-10 keV). 

UVOT took a finding chart exposure of 100 seconds with the White
(160-650 nm) filter starting 459 seconds after the BAT trigger. There
is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image
   RA(J2000) =	23h 08m 52.39s (= 347.2183d)   
   DEC(J2000) = +10d 43' 20.3" (= 10.7223d) 
with a 1-sigma error radius of about 0.5 arc sec. This position is 
3.0 arcseconds from the center of the XRT error circle. The estimated 
magnitude is 19.4 with a 1-sigma error of about 0.5 mag. 
No correction has been made for galactic reddening of E(B-V) = 0.040.
Looking for U.S. government information and services? Visit