Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 12335

Subject
GRB 110915A: Swift detection of a burst
Date
2011-09-15T13:29:30Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
S. T. Holland (CRESST/USRA/GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), D. N. Burrows (PSU),
S. Campana (INAF-OAB), J. R. Cummings (NASA/UMBC),
P. D'Avanzo (INAF-OAB), P. A. Evans (U Leicester), C. Gronwall (PSU),
E. A. Hoversten (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC),
A. Melandri (INAF-OAB), P. T. O'Brien (U Leicester),
P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA),
M. H. Siegel (PSU), C. A. Swenson (PSU) and G. Tagliaferri (INAF-OAB)
report on behalf of the Swift Team:

At 13:20:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 110915A (trigger=503219).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 310.851, -0.709 which is 
   RA(J2000)  =  20h 43m 24s
   Dec(J2000) = -00d 42' 33"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows multiple peaks
with a total duration of about 95 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~68 sec after the trigger. 

The XRT began observing the field at 13:22:00.5 UT, 76.1 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 310.8242, -0.7231 which is equivalent to:
    RA(J2000)  = 20h 43m 17.80s
    Dec(J2000) = -00d 43' 23.1"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 108 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 84 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
0.06. 

Burst Advocate for this burst is S. T. Holland (Stephen.T.Holland AT nasa.gov). 
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.)
Looking for U.S. government information and services? Visit USA.gov