GRB 221009A: Upper limits from HAWC 8 hours after trigger
Abstract
reports observations of GRB 221009A which was detected by Swift (Kennea et al. GCN #32635), Fermi-GBM (Veres et al. GCN #32636, Lesage et al. GCN #32642), Fermi-LAT (Bissaldi et al. GCN #32637), and the IPN (Svinkin et al. GCN #32641). We use the position measured by Fermi LAT (GCN #32658), located at: RA = 288.282, Dec = 19.495 (0.027 deg 90% containment radius) This position started transiting over HAWC at 21:19:57 UTC on 2022/10/09 (~8 hours after the trigger time) and ended at 03:42:07 UTC on 2022/10/10. Assuming a power law spectra with index of -2.0 we found no significant detection in the region. We proceeded to calculate the 95% upper limit on the flux at 1 TeV: 4.16e-12 (TeV cm2 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 3.14 sr and surveys <5/6 of the sky every day. It is sensitive to gamma rays from 300 GeV to 100 TeV.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- October 2022
- Bibcode:
- 2022GCN.32683....1A