IceCube-211116A
GCN Circular 31085
Subject
IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
Date
2021-11-16T11:53:55Z (4 years ago)
From
Cristina Lagunas Gualda at DESY <cristina.lagunas@desy.de>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 2021/11/16 at 10:33:16.05 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_Bronze alert stream. The average astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 1.941 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection.
Due to a technical problem, the initial automated alert was not issued. Nonetheless, sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 2021/11/16
Time: 10:33:16.05 UT
RA: 42.45 (+1.39 -1.50 deg 90% PSF containment) J2000
Dec: +0.15 (+0.98 -0.94 deg 90% PSF containment) J2000
We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.
There are no Fermi-LAT 4FGL sources inside of the 90% error contour. The closest source is 4FGL J0253.2-0124, located at RA 43.32 deg and dec -1.4 deg (J2000), 1.78 deg away from the best-fit position.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu
GCN Circular 31090
Subject
IceCube-211116A: No neutrino counterpart detected with ANTARES
Date
2021-11-17T12:37:45Z (4 years ago)
From
Antoine Kouchner at ANTARES Collaboration <kouchner@apc.in2p3.fr>
Alexis Coleiro (APC/Universite 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 bronze track event IceCube-211116A (GCN #31085 <https://gcn.gsfc.nasa.gov/gcn3/31085.gcn3>). The reconstructed origin was 47 degrees below the horizon for ANTARES at the time of the alert.
No muon neutrino candidate events were recorded within 90% error box of the IceCube event during a +/- 1h time-window centered on the IceCube event time, and over which the potential source remained visible with a limited lifetime of ~50% due to acquisition instabilities. This leads to a preliminary 90% confidence level upper limit on the muon-neutrino radiant fluence from a point source of about 16 GeV.cm^-2 over the energy range 3 TeV ���3.5 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 26 GeV.cm^-2 (640 GeV - 320 TeV) for an E^-2.5 spectrum.
A search over an extended time window of +/- 1 day has also yielded no detection (50% visibility with ~40% lifetime).
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 31091
Subject
Fermi-LAT Gamma-ray Observations of IceCube-211116A
Date
2021-11-17T14:39:35Z (4 years ago)
From
Simone Garrappa at DESY <simone.garrappa@desy.de>
S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and R. de
Menezes (Univ. of Wuerzburg, Univ. of Sao Paulo) on behalf of the
Fermi-LAT collaboration:
We report an analysis of observations of the vicinity of the high-energy
IC211116A neutrino event (GCN 31085) with all-sky survey data from the
Large Area Telescope (LAT), on board the Fermi Gamma-ray Space
Telescope. The IceCube event was detected on 2021-11-16 at 10:33:16.05
UT (T0) with J2000 position RA = 42.45 (+1.39, -1.50) deg, Decl. = +0.15
(+0.98, -0.94) deg (90% PSF containment). No cataloged gamma-ray (>100
MeV) source is located within the 90% IC211116A localization region.
We searched for intermediate (days to years) timescale emission from a
new gamma-ray transient source. Preliminary analysis indicates no
significant (> 5 sigma) new excess emission (> 100 MeV) at the IC211116A
best-fit position. Assuming a power-law spectrum (photon index = 2.0
fixed) for a point source at the IC211116A best-fit position, the >100
MeV flux upper limit (95% confidence) is < 3.4e-10 ph cm^-2 s^-1 for
~13-years (2008-08-04 to 2021-11-16 UTC), and < 1.1e-8 (< 5.4e-7) ph
cm^-2 s^-1 for a 1-month (1-day) integration time before T0.
Since Fermi normally operates in an all-sky scanning mode, regular
monitoring of this source will continue. For these observations the
Fermi-LAT contact persons are S. Garrappa (simone.garrappa at desy.de)
and S. Buson (sara.buson at uni-wuerzburg.de).
The Fermi-LAT is a pair conversion telescope designed to cover the
energy band from 20 MeV to greater than 300 GeV. It is the product of an
international collaboration between NASA and DOE in the U.S. and many
scientific institutions across France, Italy, Japan and Sweden.
GCN Circular 31092
Subject
IceCube-211116A: Upper limits from a search for additional neutrino events in IceCube
Date
2021-11-17T17:55:44Z (4 years ago)
From
Alex Pizzuto at ICECUBE/U of Wisconsin <pizzuto@wisc.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-211116A (https://gcn.gsfc.nasa.gov/gcn3/31085.gcn3) in a time range of 1000 seconds centered on the alert event time (2021-11-16 10:24:56.050 UTC to 2021-11-16 10:41:36.050 UTC) during which IceCube was collecting good quality data. Excluding the event
that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-211116A. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-211116A ranges from 1.4e-01 to 1.5e-01 GeV cm^-2 in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 3e+02 GeV and 2e+05 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2021-11-15 10:33:16.050 UTC to 2021-11-17 10:33:16.050 UTC). In this case, we report a p-value of 1.0, consistent with no significant excess of track events. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-211116A is 1.6e-01 GeV cm^-2 in a 2 day time window.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at
the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can
be reached at roc@icecube.wisc.edu<mailto:roc@icecube.wisc.edu>.
[1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021)
GCN Circular 31118
Subject
IceCube-211116A: not observable by Fermi-GBM
Date
2021-11-24T20:39:29Z (4 years ago)
From
Cori Fletcher at USRA <cfletcher@usra.edu>
C. Fletcher (USRA) reports on behalf of the Fermi-GBM team:
At the time of the neutrino candidate IceCube-211116A
(GCN 31085), Fermi was passing through the South Atlantic
Anomaly from 9.0 minutes prior until 8.2 minutes after the trigger
time; therefore the GBM detectors were disabled.