HAWC-201019A
GCN Circular 28734
Subject
HAWC-201019A: not observable by Fermi-GBM
Date
2020-10-21T22:01:02Z (5 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team:
The HAWC Burst Monitor detected the burst signal HAWC-201019A (GCN 28709) with the
reported position:
RA: 203.148 deg (J2000)
Dec: 29.717 (J2000)
which was occulted by the Earth for Fermi-GBM from approximately 14.5 minutes
prior until 14.8 minutes after event time. Therefore, the GBM observations are not
constraining for prompt gamma-ray emission.
GCN Circular 28729
Subject
HAWC-201019A: No Neutrino Counterpart detected with ANTARES
Date
2020-10-21T20:25:59Z (5 years ago)
From
Antoine Kouchner at ANTARES Collaboration <kouchner@apc.in2p3.fr>
Alexis Coleiro (APC/Univ de Paris) and Damien Dornic (CPPM/CNRS) on behalf of the ANTARES Collaboration.
Using data from the ANTARES detector, we have performed a follow-up analysis of the recently reported HAWC-201019A alert (GCN 28709 <https://gcn.gsfc.nasa.gov/gcn3/28709.gcn3>).
No up-going muon neutrino candidate events were detected within the error box of the HAWC event during a +/- 1h time-window centered on the HAWC event time (T0), and over which the potential source remained visible all time in the up-going field of view of ANTARES. At T0, the elevation of the alert is -15 degrees below the horizon for ANTARES.
This leads to a preliminary 90% confidence level upper limit on the muon-neutrino radiant fluence from a point source of about 17 GeV.cm^-2 over the energy range 7 TeV ��� 6 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and about 37 GeV.cm^-2 (1 - 630 TeV) for an E^-2.5 spectrum. A search over an extended time window of +/-1 day has also yielded no detection (32% visibility).
ANTARES <http://antares.in2p3.fr/>is the largest undersea neutrino detector (Mediterranean Sea) and it is primarily sensitive to astrophysical neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky.
GCN Circular 28709
Subject
Alert from the HAWC Burst Monitor HAWC-201019A
Date
2020-10-21T00:08:10Z (5 years ago)
From
Hugo Ayala at Pennsylvania State University <hgayala@psu.edu>
The HAWC Collaboration (http://www.hawc-observatory.org/collaboration/)
reports:
On 2020-10-19, at 21:43:42 UT, HAWC detected a burst signal
from its Burst Monitoring named HAWC-201019A. This monitor system looks
for excesses above the expected background in time windows of 0.2, 1, 10
and 100 seconds.
This event was found in the 100-second time window starting
at the reported trigger time.
The position of the alert is
RA (J200): 203.148 deg
Dec (J2000): 29.717 deg
Location uncertainty (68% containment): 0.6 deg (statistical only).
The monitor system found that this alert has a false alarm rate of 2.37
alert(s) per year.
We encourage follow-up observations of the HAWC alert region. We however
note that it is
consistent with background expectation based on the observation time.
The initial automated alert is recorded here:
https://gcn.gsfc.nasa.gov/gcn/notices_amon_hawc/1009678_72.amon
We note that a quick search on the FAVA monitoring
(https://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/), an old
alert, FAVA_223_2, is 0.29 deg away from HAWC-201019A, which
occurred on 2012-11-05 15:43:35.
See:
https://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/LightCurve.php?ra=203.148&dec=29.717
The source 4FGL J1330.7+2933 is located 0.43 deg away from HAWC-201019A
and is also positionally consistent with the FAVA event.
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.