IceCube-191122A

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


On Nov 22, 2019�� at 22:45:10.50 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 
threshold astrophysical neutrino purity for Bronze alerts is 30%. This 
alert has an estimated false alarm rate of 3.099 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/133348_80807014.amon), more
sophisticated reconstruction algorithms have been applied offline, with 
the direction refined to:

Date: 19/11/22 (yy/mm/dd)
Time: 22:45:10.50 UT
RA: 27.25 (+1.70/-2.90 deg - 90% PSF containment) J2000
Dec: -0.04 (+1.17/-1.49 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.


There are no Fermi 4FGL or 3FHL catalog sources in the 90% uncertainty 
region. The nearest gamma-ray source in either catalog is 4FGL 
J0148.6+0127 at RA: 27.16 deg, Dec: 1.46 deg (1.51 deg away from the 
best-fit event position, in J2000 coordinates). This source is also 
listed as 3FHL J0148.6+0127������ and is associated with the BL Lac object 
PMN J0148+0129.


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. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, 
A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, 
D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

H.Levato
(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich, Yu. Sergienko
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L)  located in South Africa (South African Astronomical 
Observatory) was pointed to the IceCube-191122A (GCN 26276
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 ) errorbox
23 sec after notice and  55 sec after  trigger time at 2019-11-22 22:46:06 
UT, with upper limit up to  19.9 mag.  The observations began at zenith 
distance = 46 deg. The sun  altitude  is  -37.6 deg.

MASTER-Tavrida robotic telescope  located in Russia (Lomonosov MSU, SAI 
Crimea astronomical station) was pointed to the IceCube-191122A 
errorbox 28 sec after notice and  60 sec after trigger time at 2019-11-22 
22:46:10 UT, with upper limit up to  15.8 mag. The observations began at 
zenith distance = 62 deg. The sun  altitude  is -61.3 deg.

MASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) was 
pointed to the IceCube-191122A errorbox 54 sec after notice and  87 sec 
after trigger time at 2019-11-22 22:46:38 UT, with upper limit up to  19.9 mag. The 
observations began at zenith distance = 28 deg. The sun  altitude  is  -61.1 deg.

The galactic latitude b = -59 deg., longitude l = 155 deg.


Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1203628

The observation and reduction will continue.
The message may be cited

Celia Sanchez-Fernandez, (ESAC-ESA, Spain) James Rodi (IAPS-Roma, Italy)
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
S. Mereghetti (INAF IASF-Milano, Italy)
A. Coleiro (APC, France)
on behalf of the INTEGRAL multi-messenger collaboration:
https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration

The INTEGRAL spacecraft has a highly elliptical orbit and the
instruments are not acquiring science data during perigee passage,
every 2.6 days to prevent radiation-induced damages. Unfortunately, at
the time of the IceCube-191122A (2019-11-22 22:45:10) the spacecraft
was preparing to the start the observations after the perigee passage
between the orbits number 2162 and 2163 and no scientific instrument
data are available between 2019-11-22T19:36:55 and
2019-11-23T04:41:51.

S. Garrappa (DESY-Zeuthen) and S. Buson (Univ. of Wuerzburg) on behalf 
of the Fermi-LAT collaboration:

We report an analysis of observations of the vicinity of the high-energy 
IC191122A neutrino event (GCN 26276
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 ) 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 2019-11-22 22:45:10.50 UT 
(T0) with J2000 position RA = 27.25 (+1.70, -2.90) deg, Decl. = -0.04 
(+1.17, -1.49) deg 90% PSF containment. No cataloged >100 MeV gamma-ray 
sources are located within the 90% IC191122A 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 (>5sigma) new excess emission (> 100 
MeV) within the IC191122A 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 limit (95% 
confidence) is < 1.5e-10 ph cm^-2 s^-1 for ~11-years (2008-08-04 / 
2019-11-22 UTC), < 8.4e-9 (< 1.5e-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 this source the Fermi-LAT 
contact person are S. Garrappa (simone.garrappa atdesy.de 
<http://desy.de/>) and S. Buson (sara.buson atuni-wuerzburg.de 
<http://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.

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-191122A (https://gcn.gsfc.nasa.gov/gcn3/26276.gcn3
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 ) in a time
range of 2 days centered on the alert event time (2019-11-21 22:45:10.50 UTC to 2019-11-23 22:45:10.50 UTC) during which IceCube was collecting good quality data. Excluding the
event that prompted the alert, two additional track-like events are found in spatial coincidence
with the 90% containment region of IceCube-191122A. We find that these data are well described by atmospheric background expectations, with a p-value of 0.036. We accordingly derive a time-integrated muon-neutrino flux upper limit at the alert position of E^2 dN/ dE = 4.4 x 10^-5 TeV cm^-2 at 90% CL, under the assumption of an E^-2 power law. 90% of events IceCube would detect from a source at this declination with an E^-2 spectrum are approximately between 1 TeV and 10 PeV.

A subsequent search was performed to include the month of data prior to the alert event (2019-10-22 22:45:10.50 UTC to 2019-11-23 22:45:10.50 UTC). In this case, we report a p-value of 1.0, consistent with no significant excess of track-like events, and a corresponding time-integrated muon-neutrino flux upper limit assuming an E^-2 spectrum (E^2 dN/dE) of
 6.3 x 10^-5 TeV cm^-2 at the 90% CL.

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>.

J. Wood (NASA/MSFC) reports on behalf of the Fermi-GBM Team:

For the IceCube high-energy neutrino candidate event 191122A (GCN 26276
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 ), 
the reported position:

RA: 27.25 (+1.70/-2.90 deg - 90% PSF containment) J2000
Dec: -0.04 (+1.17/-1.49 deg - 90% PSF containment) J2000

was occulted by the Earth for Fermi-GBM from approximately 24 minutes prior
until 11 minutes after event time. Therefore, the GBM observations are not 
constraining for prompt gamma-ray emission.

Hugo Ayala (PSU) reports on behalf of the HAWC
collaboration (http://www.hawc-observatory.org/collaboration):

On 2019/11/22 22:45:10 UTC, the IceCube collaboration reported a
track-like very-high-energy event  that has a high probability of
being an astrophysical neutrino, IceCube-191122A. Location is at
RA: 27.25 (+1.7/-2.9 deg  90% PSF containment) J2000
Dec: -0.04(+1.17/-1.49 deg 90% PSF containment) J2000
https://gcn.gsfc.nasa.gov/gcn3/26276.gcn3
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(GCN circular 26276
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 ).

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 May 2018. We searched
inside the reported IceCube error region from the circular.
The highest significance, 2.38 sigma (-0.1 post-trials),
is at RA 28.80 deg, Dec -0.90 deg J2000.
We set a time-integrated 95% CL  upper limit on gamma rays at the
maximum position of:
E^2 dN/dE =1.70e-13 (E/TeV)^-0.3 TeV cm^-2 s^-1

Search for a transient source.
Since the event was not in our field of view at the time reported,
we report the combined result for the transits before and after the
IceCube event.
Data acquisition started on Data Start: 2019/11/21 06:48:41 UTC and ended
2019/11/23 06:59:52 UTC.
The most significant location, with 2.79 sigma (0.98 post-trials),
is at RA 28.92 deg, Dec -0.19 deg (J2000).
We set a time-integrated 95% CL upper limit at the position of
maximum significance of:
E^2 dN/dE = 6.83e-12 (E/1TeV)^-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.