IceCube-251014A
GCN Circular 42300
Subject
Fermi-LAT Gamma-ray Observations of IceCube-251014A
Date
2025-10-15T20:30:22Z (3 months ago)
From
Leo Pfeiffer at University of Würzburg <pfeiffer.leo@gmail.com>
Via
Web form
L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg) and S. Garrappa (Weizmann Institute of Science) on behalf of the Fermi-LAT collaboration:
We report an analysis of observations of the vicinity of the high-energy IC251014A neutrino event (GCN 42277) 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 25-10-14 at 18:33:11.58 UTC (T0) with J2000 position RA = 2.81 (+0.48, -0.49) deg, Decl. = 2.91 (+0.49, -0.49 ) deg 90% PSF containment (J2000). No cataloged gamma-ray sources are found within the 90% IC251014A localization error (4FGL-DR4; The Fourth Fermi-LAT catalog Data Release 4, The Fermi-LAT collaboration 2023, arXiv:2307.12546).
We searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC251014A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC251014A best-fit position, the >100 MeV flux upper limit (95% confidence) is <1.9e-10 ph cm^-2 s^-1 for ~17-years (2008-08-04 / T0), <1.6e-08 (<8.0e-07) 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 this analysis, the Fermi-LAT contact person is L. Pfeiffer (leonard.pfeiffer 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 42277
Subject
IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
Date
2025-10-15T01:31:07Z (3 months ago)
From
Erik Blaufuss at University of Maryland, College Park <blaufuss@umd.edu>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 25-10-14 at 18:33:11.58 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 2.226 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection.
After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/141484_75492250.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 25-10-14
Time: 18:33:11.58 UT
RA: 2.81 (+0.48/-0.49 deg 90% PSF containment) J2000
Dec: 2.91 (+0.49/-0.49 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.
No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of the event.
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