HAWC observations of AT2021afpi / MASTER OT J030227.28+191754.5 (discovered during follow-up observations of IceCube-211125A)
ATel #15079; Hugo Ayala
on 30 Nov 2021; 20:43 UT
Credential Certification: Hugo Alberto Ayala Solares (hgayala@psu.edu)
We report the results of the HAWC observations around the position of the transient MASTER OT J030227.28+1917554.5 (ATEL #15067). This object was reported as a possible counterpart to the event IceCube-211125A. Our analysis results on the IceCube event can be found in GCN 31153.
Other ATels related to this event are #15069, #15072, #15073, #15074, #15076, and #15078.
No significant event was observed. At the time of the event, the position of the source was transiting above the HAWC detector. The start of the transit time occurred at 02:04:27 UTC and ended at 08:25:49 UTC. During this time, HAWC observes a hotspot of 1.94 sigma pre-trials at position RA=45.48 deg, Dec=19.39 deg with an uncertainty of 0.33 deg.
The spectral information, assuming a power-law with spectral index of -2.3 gives a flux normalization measurement of 6.65e-12 (+1.03e-11 -5.88e-12) TeV-1 cm-2 s-1 at 1 TeV (UL = 1.17e-11 TeV-1 cm-2 s-1).
If the spectral index is assumed to be -3.0, the significance of the hotspot increases to 2.51 sigma pre-trials. The normalization measurement becomes 2.55e-11 (+2.40e-11 -1.82e-11) TeV-1 cm-2 s-1 at 1 TeV (UL = 4.95e-11 TeV-1 cm-2 s-1).
We will update with another ATel after we perform measurements over several transits.
The HAWC contact people for this analysis are Jose Andres Garcia-Gonzalez (IF-UNAM, jagarcia@fisica.unam.mx, ITESM-EIC, anteus79@tec.mx) and Hugo Ayala (PSU, hagayala@psu.edu). HAWC is a TeV gamma-ray water Cherenkov array located in the state of Puebla, Mexico, that monitors two-thirds of the sky every day with an instantaneous field of view of ~2 sr.
HAWC website: https://www.hawc-observatory.org/
