[vsnet-grb-info 27855] Alert from the HAWC Burst Monitor HAWC-210507A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29958
SUBJECT: Alert from the HAWC Burst Monitor HAWC-210507A
DATE:    21/05/07 15:56:02 GMT
FROM:    Hugo Ayala at Pennsylvania State University  <hgayala at psu.edu>

The HAWC Collaboration  (http://www.hawc-observatory.org/collaboration/)
reports:

On May 07, 2021, at 10:38:22 UT, HAWC detected a burst signal
from its Burst Monitoring named HAWC-210507A. This monitor system looks
for excesses above the expected background in time windows of 0.2, 1, 10
and 100 seconds.
This event was found in the 10-second time window starting
at the reported trigger time.

The position of the alert is
RA (J200): 257.24 deg
Dec (J2000): 8.08 deg
Location uncertainty (68% containment): 0.4 deg (statistical only).

The monitor system found that this alert has a false alarm rate of 3.76
alert(s) per year.
We encourage follow-up observations of the HAWC alert region. We however
note that it is
consistent with background expectation based on the observation time.

The initial automated alert is recorded here:
https://gcn.gsfc.nasa.gov/notices_amon_hawc/1010067_1345.amon

HAWC is a very-high-energy gamma-ray observatory operating in Central
Mexico at latitude 19 deg. north. Operating day and night with over
95% duty cycle, HAWC has an instantaneous field of view of 2 sr and
surveys 2/3 of the sky every day. It is sensitive to gamma rays
from 300 GeV to 100 TeV.