[vsnet-grb-info 26983] GRB201216C: No significant detection in HAWC

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29086
SUBJECT: GRB201216C: No significant detection in HAWC
DATE:    20/12/18 17:04:28 GMT
FROM:    Hugo Ayala at Pennsylvania State University  <hgayala at psu.edu>

On 2020/12/16 at 23:07:31 UTC, following the trigger by Swift-BAT
and Fermi-GBM (GCN 29061, GCN 29063), HAWC observed the
position of GRB 201216C.

The position of the GRB at the time of trigger (t0) fell just inside the
field of
view of HAWC, at 40 deg from zenith. We observed the position in the time
range
[t0-100s,t0+3600s]. At the end of the analysis, the position was at 25 deg
from zenith.
We scanned this range with time bins of 100s width. The time window advances
every 20s, producing 80% overlap between different time windows.

No emission was observed. The most conservative
 flux upper-limit at 95% C.L. measured during the time range is

dN/dE = 4.05e-10 (E/TeV)^-2.0 [TeV^-1 cm^-2 s^-1]

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.