IceCube-231004A
GCN Circular 34797
Subject
IceCube-231004A - IceCube observation of a high-energy neutrino candidate track-like event
Date
2023-10-04T15:46:15Z (2 years ago)
From
Massimiliano Lincetto at Ruhr-Universitaet Bochum <lincetto@astro.ruhr-uni-bochum.de>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 2023-10-04 at 14:39:41.18 UT IceCube detected a track-like event with a high probability of being of astrophysical origin.
The event was selected by the ICECUBE_Astrotrack_GOLD alert stream.
The average astrophysical neutrino purity for Gold alerts is 50%.
This alert has an estimated false alarm rate of 0.4490 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/138415_56188508.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 2023-10-04
Time: 14:39:41.18 UT
RA: 143.79 (+1.10, -1.01 deg 90% PSF containment) J2000
Dec: -25.04 (+1.03, -1.21 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 4FGL-DR4 or 3FHL catalog sources in the 90% uncertainty region of the event. The nearest gamma-ray source in either catalog is 4FGL J0927.2+2454 at RA: 141.82 deg, Dec: -24.90 deg (1.79 deg away from the best-fit alert 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 34798
Subject
Update of IceCube-231004A - Corrected direciton
Date
2023-10-04T18:15:19Z (2 years ago)
From
Erik Blaufuss at University of Maryland, College Park <blaufuss@umd.edu>
Via
Web form
In GCN circular 34797 (https://gcn.nasa.gov/circulars/34797), the declination value was incorrectly reported. All other information was correct. The corrected refined directional information is:
Date: 2023-10-04
Time: 14:39:41.18 UT
RA: 143.79 (+1.10, -1.01 deg 90% PSF containment) J2000
Dec: +25.04 (+1.03, -1.21 deg 90% PSF containment) J2000
We apologize for the error.
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 34803
Subject
Fermi-LAT gamma-ray observations of IceCube-231004A
Date
2023-10-05T15:26:03Z (2 years ago)
From
Sara Buson at GSFC/Fermi <sara.buson@gmail.com>
Via
legacy email
J. Sinapius (DESY) , S. Garrappa (Weizmann Institute of Science), S. Buson (Univ. Wuerzburg) and C. Bartolini (INFN Bari) on behalf of the Fermi-LAT collaboration:
We report an analysis of observations of the vicinity of the IC231004A high-energy neutrino event (GCN 34797, 34798) 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 2023-10-04 at 14:39:41.18 UT UT (T0) with J2000 position RA = 143.79 (+1.10, -1.01) deg, Decl. = +25.04 (+1.03, -1.21) deg (90% PSF containment). No cataloged gamma-ray (>100 MeV; The Fermi-LAT collaboration 2022, ApJS, 260, 53) sources are located within the 90% IC231004A localization region.
We searched for intermediate (days to years) timescale emission from a new gamma-ray source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the IC231004A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC231004A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 1.6e-10 ph cm^-2 s^-1 for ~15-years (2008-08-04 to 2023-10-04 UTC), and < 1.0e-8 (< 1.3e-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 weizmann.ac.il), 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 34805
Subject
IceCube-231004A: No significant detection in HAWC
Date
2023-10-05T19:38:31Z (2 years ago)
From
Hugo Ayala at Pennsylvania State University <hgayala@psu.edu>
Via
legacy email
Hugo Ayala (PSU) reports on behalf of the HAWC
collaboration (http://www.hawc-observatory.org/collaboration):
On 2023/10/04 14:39:41.18 UTC, the IceCube collaboration reported a
track-like very-high-energy event that has a high probability of
being an astrophysical neutrino, IceCube-231004A. Location is at
RA: 143.79 (+1.10/-1.01 deg 90% PSF containment) J2000
Dec: 25.04 (+1.03/-1.21 deg 90% PSF containment) J2000
(GCN circular 34791,34792).
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 October 2021. We searched
inside the reported IceCube error region.
The most significant location, with p-value 2.19e-03 (5.13e-02
post-trials),
is at RA 144.67 deg, Dec +24.91 deg (±0.42 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 = 1.11e-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 2023/10/04 06:13:44 UTC and ended
2023/10/04 18:28:44 UTC.
The most significant location, with p-value 3.14e-02 (0.53 post-trials),
is at RA 143.17 deg, Dec +24.79 deg (±0.26 deg 68% containment) J2000.
We set a time-integrated 95% CL upper limit at the position of
maximum significance of:
E^2 dN/dE = 1.67e-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.
GCN Circular 34806
Subject
IceCube-231004A: Upper limits from a search for additional neutrino events in IceCube
Date
2023-10-06T18:38:44Z (2 years ago)
From
Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu>
Via
Web form
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-231004A (https://gcn.nasa.gov/circulars/34798) in a time range of 1000 seconds centered on the alert event time (2023-10-04 14:31:21.180 UTC to 2023-10-04 14:48:01.180 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-231004A. 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-231004A is 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 8e+04 GeV.
A subsequent search was performed including 2 days of data centered on the alert event time (2023-10-03 14:39:41.180 UTC to 2023-10-05 14:39:41.180 UTC). In this case, we report a p-value of 1.00, 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-231004A is 1.7e-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.
[1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021)
GCN Circular 34810
Subject
IceCube-231004A: One Candidate Counterpart from the Zwicky Transient Facility
Date
2023-10-10T17:57:45Z (2 years ago)
From
Simeon Reusch at DESY <simeon.reusch@desy.de>
Via
Web form
Simeon Reusch (DESY), Robert Stein (Caltech), Sven Weimann (Ruhr University Bochum), Jannis Necker (DESY) and Anna Franckowiak (DESY/Ruhr University Bochum) report:
On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations:
As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IC231004A (Lincetto et al, GCN 34797) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2023-10-05 11:54 UTC, approximately 21.3 hours after event time. We covered 84.2% (3.1 sq deg) of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag.
The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019). We are left with the following candidate counterpart:
+-----------------------------------------------------------------+
| IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr |
+-----------------------------------------------------------------+
| AT2023uqf | 143.4548956 | +25.1158103 | r | 20.51 | 0.11 |
+-----------------------------------------------------------------+
AT2023uqf (ZTF23abidzvf) has a g-r color of 0.1 +/- 0.1 mag, no ZTF pre-detections and it is slowly rising. Spectroscopic observations of this source are planned, and monitoring of the neutrino localization will continue as part of our standard 10-day monitoring program.
ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France.
GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949.
Alert distribution service provided by DIRAC@UW (Patterson et al. 2019).
Alert database searches are done by AMPEL (Nordin et al. 2019).
Alert filtering is performed with nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf).
GCN Circular 34851
Subject
IceCube-231004A: Upper limits from Fermi-GBM Observations
Date
2023-10-20T15:50:36Z (2 years ago)
From
Joshua Wood at NASA/MSFC <joshua.r.wood@nasa.gov>
Via
Web form
J. Wood (NASA/MSFC), Eric Burns (LSU), Michelle Hui (NASA/MSFC) report on behalf of the Fermi-GBM team:
For the IceCube high-energy neutrino candidate event IceCube-231004A
(GCN 34797), at the event time Fermi-GBM was observing the reported
neutrino location at:
RA: 143.79 (+1.10, -1.01 deg 90% PSF containment) J2000
Dec: -25.04 (+1.03, -1.21 deg 90% PSF containment) J2000
There was no Fermi-GBM onboard trigger around the event time of the
neutrino candidate. An automated, blind search for short gamma-ray
bursts below the onboard triggering threshold in Fermi-GBM also
identified no counterpart candidates. The GBM targeted search,
the most sensitive, coherent search for GRB-like signals,
was run from +/-30 s around the neutrino candidate time.
From this search, no significant signal was found related
to IceCube-231004A.
We set upper limits on impulsive gamma-ray emission to aid
theoretical modeling of the potential optical counterpart
AT2023uqf/ZTF23abidzvf (GCN 34837). Using the representative
soft, normal, and hard GRB-like templates described in
arXiv:2308.13666, we set the following 3 sigma flux upper limits over
10-1000 keV (in units of 10^-7 erg/s/cm^2):
Timescale Soft Normal Hard
-------------------------------------------
0.128 s: 2.9 4.2 7.3
1.024 s: 0.9 1.4 2.3
8.192 s: 0.3 0.4 0.6
Assuming the reported redshift z = 0.1503 (GCN 34837), we estimate
the following intrinsic luminosity upper limits over
the 1 keV-10 MeV energy range (in units of 10^49 erg/s):
Timescale Soft Normal Hard
------------------------------------
0.128s: 2.8 3.7 10.6
1.024s: 0.8 1.2 3.3
8.192s: 0.3 0.3 0.9
These results are preliminary.