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GCN Circular 3997

Subject
Swift-BAT trigger 155535 is definitely not a GRB
Date
2005-09-17T15:46:06Z (19 years ago)
From
Hans Krimm at NASA-GSFC <krimm@milkyway.gsfc.nasa.gov>
D. Grupe (PSU), H. Krimm (GSFC/USRA), P. Roming (PSU), P. Brown (PSU),
D. Burrows (PSU), J. Kennea (PSU), D. Palmer (LANL), A. Parsons (GSFC)
on behalf of the Swift team:

Using the full BAT data from the recent telemetry downlink, the Swift-BAT
trigger 155535 (at 13:19:00 UT on 17 September 2005) is not due to a GRB.
This was a cascade shower event from a high energy cosmic ray in the 
spacecraft.

The XRT started to observe the field of trigger #155535 175 s after 
the trigger.
The field was observed for 618 s in PC mode, but XRT did not detect any source.

The UVOT began observing the position of trigger #155535 at 13:20:19.2 UT, 80 s
after the BAT trigger. In the 100 s V-band image, no new source is detected
with respect to the DSS. The estimated extinction in this direction is
A_V ~0.5 magnitudes. The UVOT image gives 100% coverage of the BAT 
error circle.
The BAT source is located in a crowded star field.
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