[vsnet-grb-info 25869] IceCube-200614A: No significant detection in HAWC

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27969
SUBJECT: IceCube-200614A: No significant detection in HAWC
DATE:    20/06/16 18:18:30 GMT
FROM:    Hugo Ayala at Pennsylvania State University  <hgayala at psu.edu>

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.