GCN Circular 27969
Hugo Ayala (Penn State) reports on behalf of the HAWC collaboration (http://www.hawc-observatory.org/collaboration): On 2020/06/14 12:41:21 UTC, the IceCube collaboration reported a track-like very-high-energy event that has a high probability of being an astrophysical neutrino, IceCube-200614A. Location is at RA: 33.84 (+4.77/-6.39 deg 90% PSF containment) J2000 Dec: 31.61 (+2.75/-2.28 deg 90% PSF containment) J2000 (GCN circular 27941). We performed two types of analyses for the follow-up. The first is for a steady source in archival data and the second is a search for a transient source. We assume a power-law spectrum with an index of -2.3 for both analyses. Search for a steady source in archival data: The archival data spans from November 2014 to May 2018. We searched inside the reported IceCube error region. The most significant location, with p-value 3.02e-4 (8.27e-2 post-trials), is at RA 35.51 deg, Dec 33.55 deg (��0.16 deg 68% containment) J2000. We set a time-integrated 95% CL upper limit on gamma rays at the maximum position of: E^2 dN/dE = 3.85e-13 (E/TeV)^-0.3 TeV.cm^-2.s^-1 Search for a transient source. Since the IceCube event fall inside the HAWC field of view, we report on the result for the transit of the IceCube position. Data acquisition started on 2020/06/13 18:10:07 UTC and ended 2020/06/14 18:32:13 UTC. The most significant location, with p-value 1.35e-3 (3.20e-1 post-trials), is at RA 38.63 deg, Dec -30.55 deg (��0.09 deg 68% containment) J2000. We set a time-integrated 95% CL upper limit at the position of maximum significance of: E^2 dN/dE = 1.46e-11 (E/TeV)^-0.3 TeV.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.