IceCube-230122A
GCN Circular 33204
Subject
IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
Date
2023-01-22T05:24:48Z (2 years ago)
From
Erik Blaufuss at U. Maryland/IceCube <blaufuss@umd.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 2023-01-22 03:50:02.00 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 3.62 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/137571_16496893.amon), more
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 2023-01-22
Time: 03:50:02.00 UT
RA:16.79 (+3.17 / -2.56 deg 90% PSF containment) J2000
Dec: +7.78 (+3.44 / -3.26 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 four known gamma-ray sources listed in the Fermi 4FGL catalog within the 90% uncertainty region of the event. The nearest one is 4FGL J0100.3+0745 (RA: 15.09 deg, Dec: 7.76 deg in J2000 coordinates), 1.68 deg away from the best-fit event 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 33212
Subject
Fermi-LAT gamma-ray observations of IceCube-230122A
Date
2023-01-23T19:59:55Z (2 years ago)
From
Simone Garrappa at DESY <simone.garrappa@desy.de>
S. Garrappa (Ruhr-Universitaet Bochum), S. Buson (Univ. of Wuerzburg)
and J. Sinapius (DESY-Zeuthen) on behalf of the Fermi-LAT collaboration:
We report an analysis of observations of the vicinity of the IC230122A
high-energy neutrino event (GCN 33204) 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 2023-01-22 at 03:50:02.00
UT (T0) with J2000 position RA = 16.79 (+3.17, -2.56) deg, Decl. = +7.78
(+3.44, -3.26) deg (90% PSF containment). Five cataloged gamma-ray (>100
MeV; The Fermi-LAT collaboration 2022, ApJS, 260, 53) sources are
located within the 90% IC230122A localization region. Based on a
preliminary analysis of the LAT data over the timescales of 1-month
prior to T0, one of these objects,�� the source 4FGL J0100.3+0745
associated to the BL Lac object GB6 J0100+0745 (at 1.68 deg offset from
the best-fit neutrino localisation), is detected at ~4 sigma level. The
flux measured for the source, is however consistent with the average
value measured in the 4FGL.
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 IC230122A
best-fit position. Assuming a power-law spectrum (photon index = 2.0
fixed) for a point source at the IC230122A best-fit position, the >100
MeV flux upper limit (95% confidence) is < 2.9e-10 ph cm^-2 s^-1 for
~14-years (2008-08-04 to 2023-01-22 UTC), and < 6.5e-9 (<1.4e-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 region will continue. For these observations the
Fermi-LAT contact persons are S. Garrappa (simone.garrappa at
ruhr-uni-bochum.de), J. Sinapius (jonas.sinapius 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 33219
Subject
IceCube-230122A: Upper limits from a search for additional neutrino events in IceCube
Date
2023-01-24T21:47:19Z (2 years ago)
From
Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@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-230122A (https://gcn.gsfc.nasa.gov/gcn3/33204.gcn3) in a time range of 1000 seconds centered on the alert event time (2023-01-22 03:41:42.000 UTC to 2023-01-22 03:58:22.000 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-230122A. 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-230122A ranges from 1.3e-01 to 1.4e-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 2e+02 GeV and 1e+05 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2023-01-21 03:50:02.000 UTC to 2023-01-23 03:50:02.000 UTC). In this case, we report a p-value of 0.17, 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-230122A ranges from 1.5e-01 to 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.
GCN Circular 33228
Subject
IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
Date
2023-01-28T14:16:31Z (2 years ago)
From
Dingrong Xiong at Yunnan Observatories of CAS, China <xiongdingrong@ynao.ac.cn>
D. R. Xiong, J. M. Bai, Y. F. Fan, K. Ye, C. J. Wang, Y. X. Xin, B. L. Lun, J. R. Mao, X. H. Zhao, L. Xu, X. G. Yu, K. X. Lu, X. Ding, D. Q. Wang (Yunnan Observatories), A. J. Castro-Tirado, E. Fernandez-Garcia, Y. D. Hu (IAA-CSIC) and C. J. Perez del Pulgar (UMA) on behalf of the BOOTES team report:
On 2023-01-22 03:50:02.00 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The nearest one is 4FGL J0100.3+0745 within the 90% uncertainty region of the event, 1.68 deg away from the best-fit event position (GCN 33204, 33212).
We observed the BL Lac object 4FGL J0100.3+0745 and the best-fit position of IceCube-230122A with BOOTES-2/TELMA robotic telescope.The magnitudes were calculated using bright stars in the same frame and the SDSS DR16 catalogue as reference. We did not detect any optical source within the best-fit position, and also the optical counterpart of the 4FGL J0100.3+0745.
The upper limits of magnitudes (without being corrected for Galactic extinction) are given as follows.
Sources | Tmid-T0 (day) | UT (start) | Upper Limit (error) | Exposure Time | Filter
--------------------------------------------------------------------------------------------------------------
Best-fit position | 0.764 | 23-01-22 22:10:44.8 | 18.79 (0.22) | 2*300s (co-added) | Clear
4FGL J0100.3+0745 | 0.699 | 23-01-22 20:36:22.3 | 19.51 (0.03) | 8*300s (co-added) | Clear
---------------------------------------------------------------------------------------------------------------
The Burst Optical Observer and Transient Exploring System (BOOTES) is a world-wide automatic telescope network which aims to repaid follow-up of transient and astrophysical sources in the sky for which the first station was installed in 1998 (Hu et al. 2021). The BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) in Algarrobo Costa (Malaga, Spain). We acknowledge the support of these staffs from the BOOTES telescope networks.