HAWC follow-up observations of the KM3NeT neutrino event KM3-230213A
ATel #17069; Dezhi Huang (UMD) for the HAWC Collaboration
on 7 Mar 2025; 17:31 UT
Credential Certification: Dezhi Huang (dezhih@umd.edu)
Subjects: Gamma Ray, TeV, Neutrinos
We report results from the High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory on the extremely high-energy neutrino event KM3-230213A recently published by the KM3NeT Collaboration (Nature, 2024).
HAWC conducted a search for gamma-ray emission at the neutrino event position reported by KM3NeT over four different intervals. As the HAWC Observatory was undergoing maintenance during the KM3NeT detection, HAWC's follow-up observations began approximately 21 hours after the neutrino event. The event location first entered HAWC's field of view around February 14, 2023, at 00:50:00 UTC, with two complete transit covered between 21 and 69 hours after the KM3NeT detection. Subsequent searches were conducted one week, one month, and one year after the event, each with an average exposure of approximately 5 hours per transit as the event location passed through HAWC's field of view. Using a likelihood analysis and assuming a power-law spectral model with a fixed index of -2.7 and the fixed position reported by KM3NeT, no significant gamma-ray emission was detected in any of the intervals. We, therefore, derived the following 95% confidence-level upper limits on the gamma-ray flux (I_0) at 1 TeV:
21-69 hours interval < 9.96e-11 TeV-1 cm-2 s-1
One-week interval < 6.96e-11 TeV-1 cm-2 s-1
One-month interval < 5.52e-11 TeV-1 cm-2 s-1
One-year interval < 8.06e-13 TeV-1 cm-2 s-1
The HAWC contact people for this analysis HAWC is Dezhi Huang (dezhih@umd.edu) 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. Additional information about HAWC and its monitoring capabilities can be found at: https://www.hawc-observatory.org/
