IceCube-190124A

The IceCube Collaboration (http://icecube.wisc.edu/) reports:

On January 24, 2019, IceCube detected a track-like, very-high-energy event with a high probability of being of astrophysical origin. The event was identified by the High Energy Starting Event (HESE) track selection. The IceCube detector was in a normal operating state. HESE tracks have a neutrino interaction vertex inside the detector and produce a muon that only partially traverses the detector volume, and have a high light level (a proxy for energy). An inspection of the event does not reveal any feature to rule out this event as an astrophysical candidate.

After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon/9759013_132077.amon), more 
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2019/01/24
Time: 03:43:54.79 UT
RA: 307.40 [-0.9,+0.8] (deg  90% PSF containment) J2000
Dec: -32.18 [-0.7,+0.7] (deg 90% PSF containment) J2000

Within the 90% containment region there are no 3FGL or 3FHL objects. We encourage follow-up of this alert by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.

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

------------------------------------------------------------------------------------
Erik Blaufuss                      email: blaufuss@umd.edu
Department of Physics       http://icecube.umd.edu/~blaufuss
University of Maryland       Phone: 301-405-6077
College Park, MD 20742   Office: PSC 2208E
"Any chance collision, and I light up in the dark."
------------------------------------------------------------------------------------

S. Buson (Univ. of Wuerzburg, UMBC), R. Angioni (MPIfR-Bonn), S. Garrappa (DESY-Zeuthen), F. Krauss (UvA), M. Kreter (North-West University, Potchefstroom), S. Cutini (Univ. of Perugia), D. Kocevski (NASA/MSFC)  on behalf of the Fermi-LAT collaboration:

We report an analysis of observations of the vicinity of the very high-energy IC190124A neutrino event (GCN 23785
Loading...
 
 ) 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 2019-01-24 03:43:54.79 UTC with J2000 position RA = 307.40 (-0.9,+0.8) deg, Decl. = -32.18 (-0.7,+0.7) deg 90% PSF containment. No catalogued >100 MeV gamma-ray source is found within the 90% IC190124A localization error.
We searched for the existence of intermediate (months to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5 sigma) new excess emission (0.1 - 300 GeV) within the IC190124A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IceCube best-fit position, the >100 MeV flux upper limits (95% confidence) are < 3e-10 ph cm^-2 s^-1 for ~10.5-years (2008-08-04 / 2019-01-24 UTC) integration time, < 1.5e-9 ph cm^-2 s^-1 for one year (2018-01-24 / 2019-01-24 UTC) integration time, and < 7.6e-9 ph cm^-2 s^-1 for one month (2018-12-25 / 2019-01-24 UTC) integration time before the IceCube IC190124A neutrino detection.
Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this source the Fermi-LAT contact persons are S. Buson (sara.buson at astro.uni-wuerzburg.de <http://astro.uni-wuerzburg.de/>) and R. Angioni (angioni at mpifr-bonn.mpg.de <http://mpifr-bonn.mpg.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.

Alexis Coleiro (APC) and Damien Dornic (CPPM)  report on behalf of the ANTARES Collaboration:

Using data from the ANTARES detector, we have performed a follow-up analysis
of the recently reported single high-energy starting event (HESE) neutrino
IceCube-190124A (GCN 23785
Loading...
 
 ). The reconstructed origin was 44 degrees below
the horizon for ANTARES. 

No up-going muon neutrino candidate events were recorded within 3 degrees 
of the IceCube event coordinates during a +/- 1h time-window centered on 
the IceCube event time, and over which the potential source remained visible 
all time. A search over an extended time window of +/- 1 day has also yielded 
no detection (70% visibility). This leads to a preliminary 90% confidence 
level upper limit on the muon-neutrino fluence from a point source of 15 
GeV.cm^-2 over the energy range 3.1 TeV - 3.6 PeV (the range corresponding 
to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 25 
GeV.cm^-2 (610 GeV - 316 TeV) for an E^-2.5 spectrum. 

ANTARES is the largest neutrino detector installed in the 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.

The IceCube Collaboration (http://icecube.wisc.edu/) reports:

IceCube has performed a search for additional track-like muon neutrino events arriving from the direction 
of IceCube-190124A (https://gcn.gsfc.nasa.gov/gcn3/23785.gcn3
Loading...
 
 ) in a time range of 2 days centered on the alert 
event time (2019-01-23 03:43:54.79 UTC to 2019-01-25 03:43:54.79 UTC) during which IceCube was collecting good quality data. Excluding 
the event that prompted the alert, 1 additional track-like event is found in spatial coincidence with the 
90% PSF containment of IceCube-190124A. We find that this additional event is well described by atmospheric 
background expectations, with a p-value of 0.07. Accordingly, these data would represent a time-integrated 
muon-neutrino flux upper limit assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 6.32 x 10^-4 TeV cm^-2  
for this observation period.

A subsequent search was performed to include the previous month of data (2018-12-24 03:43:54.79 UTC to 2019-01-25 03:43:54.79 UTC). 
In this case, 2 additional track-like events are found in spatial coincidence with the 90% PSF containment of IceCube-190124A. For this search, we report a p-value of 0.20, consistent with no significant excess of track events, and a corresponding
time-integrated muon-neutrino flux upper limit assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 8.81 x 10^-4 TeV cm^-2.

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.

V. Savchenko, C. Ferrigno, E. Bozzo, T. Courvoisier
(ISDC/UniGE, Switzerland)
E. Kuulkers (ESTEC/ESA, The Netherlands)
C. Sanchez (ESAC/ESA, Spain)
S. Mereghetti (INAF IASF-Milano, Italy)
J. Rodi, A. Bazzano, L. Natalucci, F. Panessa, P. Ubertini
(IAPS-Roma, Italy)
J. Chenevez, S. Brandt (DTU, Denmark)
R. Diehl, A. von Kienlin (MPE, Germany)
D. Gotz, Ph. Laurent, A. Goldwurm
(DRF/Irfu/DAp Saclay/CEA, France)
A. Coleiro (APC, France)
L. Hanlon, A. Martin-Carrillo (UCD, Ireland)
J.-P. Roques, E. Jourdain, P. von Ballmoos (IRAP, France)
A. Domingo, J. M. Mas-Hesse (CAB/CSIC-INTA, Spain)
A. Lutovinov, R. Sunyaev (IKI, Russia)


Using INTEGRAL we have performed a search for a prompt gamma-ray
counterpart of the cosmic neutrino candidate IceCube-190124A
(GCN 23785
Loading...
 
 ).

At the time of the event (2019-01-24 03:43:54 UT, hereafter T0),
INTEGRAL was operating in nominal mode except for the SPI detector
which was undergoing annealing procedure. The peak of the neutrino
localization probability (GCN 23785
Loading...
 
 ) was at an angle of 90 deg with
respect to the spacecraft pointing axis, but from a direction such
that the IBIS instrument assembly is blocking the SPI-ACS detector.
This particularly unfavorable orientation implies considerably
suppressed responses of ISGRI, IBIS/Veto, and SPI-ACS.


The background within +/-300 seconds around the event was very
stable.�� We do not detect any significant counterparts and estimate
a 3-sigma upper limit on the 75-2000 keV fluence of 5.1e-07 erg/cm^2
for a burst lasting less than 1 s with a characteristic short GRB
spectrum (an exponentially cut off power law with alpha=-0.5 and
Ep=600 keV) occurring at any time in the interval within 300 s
around T0.

For a typical long GRB spectrum (Band function with alpha=-1,
beta=-2.5, and Ep=300 keV), the derived peak flux upper limit is
~7.2e-07 (2.1e-06) erg/cm^2/s at 1 s (8 s) time scale in 75-2000
keV energy range.

A. Goldstein (USRA), R. Hamburg (UAH), and C.M. Hui (NASA/MSFC) report on
behalf of the Fermi GBM team:

���We have searched the Fermi Gamma-ray Burst Monitor data for gamma-ray
counterpart to IceCube-190124A (GCN 23785
Loading...
 
 ). The closest onboard trigger
occurred approximately 1 hour prior to the neutrino event time and was
identified as a terrestrial gamma-ray flash unassociated with the neutrino.
The ground-based untargeted search of GBM data did not find any significant
candidates within +/- 1 hour of the event time. The targeted search
([1],[2]) was also run +/- 150 s around the event time, and no significant
candidates were found.

We set the following impulsive 3 sigma flux upper limits (10-1000 keV) in a
300 s window around the neutrino time based on various GRB spectra, ranging
from soft to hard spectra.

Timescale  Upper limit (erg/s/cm^2)
-----------------------------------
1 s  :      1.6 -  7.5 (e-07)
10 s :      5.0 - 23.4 (e-08)
100 s:      1.6 -  7.5 (e-08)

[1] L. Blackburn et al. 2015, ApJS 217, 8
[2] A. Goldstein et al. arXiv:1612.02395
Loading...
 
 
"