[vsnet-grb-info 12223] Swift Trigger 530441 is a false trigger

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13612
SUBJECT: Swift Trigger 530441 is a false trigger
DATE:    12/08/09 06:52:00 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

B. N. Barlow (PSU), S. D. Barthelmy (GSFC),
J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), D. M. Palmer (LANL) and
P. Romano (INAF-IASFPA) report on behalf of the Swift Team:

At 06:14:54 UT, the Swift Burst Alert Telescope (BAT) found a 
marginal-significance peak in the vicinity of IGR J16283-4838 
(trigger=530441).  Swift did not immediately slew to the burst 
due to the low priority the onboard software gives to this source. 
The BAT on-board calculated location is 
RA, Dec 246.932, -48.541 which is 
   RA(J2000) = 16h 27m 44s
   Dec(J2000) = -48d 32' 26"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is usual for an image trigger, there
is no obvious signal in the light curve. 

This image peak is almost certainly a noise fluctuation in an
image.  As part of an ongoing sensitivity enhancement program,
we generate a GCN notice whenever a marginal significance
peak is found within 12 arcminutes of a source in the on-board
catalog.  Given the low significance (6.43 sigma) and inconsistent
position (0.126 degrees from the catalogued position),
there is no reason to believe that this peak is due to the
astrophysical source.