IceCube-201114A

Robert Morgan (U of Wisconsin-Madison), Alyssa Garcia (U of Michigan), Ken Herner (Fermilab), Robert Gruendl (NCSA), Keith Bechtol (U of Wisconsin-Madison), Kathy Vivas (NOIRLab), Clara E. Mart�nez-V�zquez (NOIRLab), Claudio Aguilera (NOIRLab), Alex Drlica-Wagner (Fermilab), Julio Carballo-Bello (U de Tarapac�), Peter Ferguson (Texas A&M U), Alex Goater (U of Surrey), Jeff Cooke (Swinburne U), Timothy M. C. Abbott (NOIRLab), Guy Stringfellow (U of Colorado-Boulder), Amy Miller (Leibniz-Institut f�r Astrophysik Potsdam)


We triggered the Dark Energy Camera (DECam) at Cerro Tololo Inter-American Observatory in Chile on the localization area of the GOLD neutrino event detected by IceCube (IceCube-201114A, GCN 28887
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 ). Observations took place on 2020-11-14, 2020-11-15, 2020-11-18, and 2020-11-24 in the gri bands, using 150 second exposures, and reaching 10-sigma limiting magnitudes of approximately 23 mag (see GCN 28947
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  for full limiting magnitudes). Each night, ~95% of the 90% localization area was covered by DECam. We reduced the DECam images using the DESGW difference imaging pipeline (Herner et al. 2020), using the 2020-11-14 images as reference images, to find candidate counterparts.


We have detected three candidate optical counterparts to IceCube-201114A using the selection methodology described in GCN 28947
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 :


| NAME           | TNS        | RA         | DEC      | HOST                  | HOST MAG_i |

| DESNU-c-882497 | AT2020aava
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  | 105.939736 | 5.514658 | PSO J105.9396+05.5147 | 19.70      |

| DESNU-d-885649 | AT2020aaxh
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  | 106.091719 | 5.509099 | PSO J106.0918+05.5091 | 19.54      |
| DESNU-e-889367 | AT2020abag
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  | 105.997798 | 5.839717 | PSO J105.9982+05.8396 | 19.48      |


The photometry reported previously for these candidates is now believed to have underestimated the real brightness of each transient. The candidates were observed to be bright during the epoch used as templates in difference imaging, which biased the estimates in GCN 28947
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  and TNS reports. Each candidate is expected to be approximately mag_i = 20 based on the relative brightness to the host in our images and the previously measured magnitude of the host galaxy.


These candidates are consistent with supernovae based on their photometric behavior in our 4 observing epochs, and high-energy neutrinos have a proposed source class of core-collapse supernovae. Spectroscopic follow-up of these mag_i ~20 objects is encouraged to characterize the objects and exclude the largest expected background of type-Ia supernovae. DESNU-e-889367 is of highest interest because it appears to be brightening and therefore possibly temporally consistent with IceCube-201114A.


Spectroscopic teams interested in performing follow-up can contact Robert Morgan (robert.morgan@wisc.edu<mailto:robert.morgan@wisc.edu>) if any additional information is needed.

Robert Morgan (U of Wisconsin-Madison), Ken Herner (Fermilab), Alyssa Garcia (U of Michigan), Robert Gruendl (NCSA), Keith Bechtol (U of Wisconsin-Madison), Kathy Vivas (NOIRLab), Clara E. Mart�nez-V�zquez (NOIRLab), Claudio Aguilera (NOIRLab), Alex Drlica-Wagner (Fermilab), Julio Carballo-Bello (U de Tarapac�), Peter Ferguson (Texas A&M U), Alex Goater (U of Surrey), Jeff Cooke (Swinburne U), Timothy M. C. Abbott (NOIRLab)


We triggered the Dark Energy Camera (DECam) at Cerro Tololo Inter-American Observatory in Chile on the localization area of the GOLD neutrino event detected by IceCube (IceCube-201114A, GCN 28887
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 ). Observations took place on 2020-11-14, 2020-11-15, and 2020-11-18 in the gri bands, using 150 second exposures, and reaching 10-sigma limiting magnitudes of approximately 23 mag*. Each night, the ~95% of the 90% localization area was covered by DECam. We reduced the DECam images using the DESGW difference imaging pipeline (Herner et al. 2020), using the 2020-11-14 images as reference images, to find candidate counterparts.


We required that candidate counterparts are (1) not found in GAIA DR2, (2) detected on 2 nights by Source Extractor with 1 of the detections also passing a machine learning artifact detection program (autoscan, Goldstein et. al 2015), (3) detected in multiple bands on at least one night, (4) not found in a spatial-temporal look-up in the Minor Planet Center or Near Earth Object Catalog, (5) not ruled out as an artifact by visual inspection.


We find one optical counterpart candidate:

| NAME           | TNS        | RA         | DEC      | HOST                  |

| DESNU-c-882497 | AT2020aava
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  | 105.939736 | 5.514658 | PSO J105.9396+05.5147 |


With photometry:

| MJD      | MAG_g | MAG_r | MAG_i |

| 59169.33 | 25.15 | 23.99 | 22.83 |

| 59172.33 | 24.08 | 23.18 | 21.87 |


We will continue to monitor this candidate with DECam over the next 2 weeks, as well as the 90% localization area of IceCube-201114A. Spectroscopic characterization of this object, and / or a spectroscopic redshift of the host is encouraged. The TNS report (https://wis-tns.weizmann.ac.il/object/2020aava/) contains DECam images of DESNU-c-882497 in the �Comments� section.


We also report non-detection in these data of the following candidates submitted via GCN thus far:
- SWIFT Source 1: GCN 28891
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- SWIFT Source 2: GCN 28891
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- 4FGL J0658.6+0636: GCN 28895
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- Fermi J0703.5+0505: GCN 28918
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  (outside area covered by DECam)


* DECam 10-sigma limiting magnitudes for these observations:
| MJD      | MAGLIM_g | MAGLIM_r | MAGLIM_i |

| 59168.33 | 23.35    | 22.87    | 22.92    |

| 59169.33 | 23.43    | 23.18    | 22.74    |

| 59172.33 | 23.24    | 23.21    | 22.49    |

J. DeLaunay (PSU), D. B. Fox (PSU), A. Keivani (Columbia U.),
J.P. Osborne (U. Leicester), F. Krauss (PSU), T. Gregoire (PSU),
P.A. Evans (U. Leicester), J.A. Kennea (PSU)
and H. A. Ayala Solares (PSU),  D.F. Cowen (PSU) report:

Swift has observed the region of Fermi J0703.5+0505 (Garrappa et al., GCN Circ. 28918
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 ), a possible counterpart to
IceCube 201114A, gathering 3.6 ks of cleaned PC mode data between 05:32 UT and 21:20 UT on 2020 November 18.

We find 2 sources in this image; the first is coincident with the 7th magnitude K0 star HD 53113 (according to
SIMBAD) and is not an X-ray source at all, but the result of optical loading from this bright object
(see https://www.swift.ac.uk/analysis/xrt/optical_loading.php).

The second source is at RA, Dec = 105.7125, +5.0311 (degrees) which corresponds to:

RA (J2000):  07h 02m 51.00s
Dec (J2000): +05d 01��� 51.8���

With an uncertainty of 4.4 arcsec (radius, 90% confidence). This position is 11.2 arcmin from the LAT position,
within the 99% contour. This source corresponds to the position of 2MASS J07024956+0500399, which SIMBAD
classifies as an RGB star. There is no known X-ray source at this position, however the RASS 3-sigma upper limit is
the equivalent of 0.017 XRT count/s (0.3-10 keV), whereas the observed count rate is significantly below this, at
(5.9 +/- 1.9, -1.6) x10^-3  ct/sec. The source shows no signs of variability, thus we cannot identify it as a new,
outbursting or fading source.

Given this, we do not believe we have found an X-ray counterpart to Fermi J0703.5+0505 or IceCube 201114A.

The 3-sigma upper limit inside the 68% confidence LAT error circle is ~3.2 x 10^-3 ct/sec (0.3-10 keV). Assuming a
power-law spectrum with nH=3 x 10^20 cm^-2 and Gamma=1.7, this corresponds to a 0.3-10 keV flux upper limit of
1.4 x 10^-13 erg cm^-2 s^-1.

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 IC201114A neutrino event (GCN 28887
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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 2020-11-14 at 15:05:31.96 UT (T0) with J2000 position RA = 105.25 (+1.28, -1.12) deg, Decl. = 6.05 (+0.95, -0.95) deg (90% PSF containment). One cataloged >100 MeV gamma-ray source is located within the 90% IC201114A localization region. This is 4FGL J0658.6+0636 (4FGL, The Fermi-LAT collaboration 2020, ApJS, 247, 33), associated with the active galaxy of uncertain type NVSS J065844+063711 (Condon et al 1998, AJ, 115, 1693) at unknown redshift. Based on a preliminary analysis of the LAT data over the timescales of 1-day and 1-month prior to T0, this object is not significantly detected (> 5 sigma).

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 IC201114A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC201114A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 2.8e-10 ph cm^-2 s^-1 for ~12-years (2008-08-04 to 2020-11-14 UTC), and < 1.6e-8 (< 2.2e-7) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0.  

Within the 90% confidence localization of the neutrino, 1.2 deg offset from the best-fit IC201114A position, an excess of gamma rays, Fermi J0703.5+0505, was detected in an analysis of the 1-day integrated LAT data (0.1 - 800 GeV) prior to T0. This putative new transient source is detected at a statistical significance >3 sigma (calculated following the prescription adopted in the 4FGL). Assuming a power-law spectrum, the excess has best-fit localization of RA = 105.89 deg, Decl. = 5.09 deg (7 arcmin 68% containment, 14 arcmin 99% containment) with best-fit spectral parameters, flux = (3.2 +/- 2.8)e-7 ph cm^-2 s^-1, index = 2.1 +/- 0.5. In a preliminary analysis of the LAT data over one month prior to T0, Fermi J0703.5+0505 is not significantly detected in the LAT data. All values include the statistical uncertainty only. This excess of gamma rays is likely driven by two > 1 GeV photons with high probability (> 90%) to be associated with this source of 21 GeV and 1.3 GeV, respectively, observed within ~4.5 hours.

Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For these observations the Fermi-LAT contact persons are S. Garrappa (simone.garrappa 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.

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-201114A (https://gcn.gsfc.nasa.gov/gcn3/28887.gcn3
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 ) in a time
range of 2 days centered on the alert event time (2020-11-13 15:05:31.96 UTC to 2020-11-15 15:05:31.96 UTC) during which IceCube was collecting good quality data. Excluding the
event that prompted the alert, one additional track-like event is found in spatial coincidence
with the 90% containment region of IceCube-201114A. We find that these data are consistent with atmospheric background expectations, with a p-value of 1.0. We accordingly derive a time-integrated muon-neutrino flux upper limit at the alert position of E^2 dN/dE = 3.2 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 3 PeV.

A subsequent search was performed to include the month of data prior to the alert event (2020-10-15 15:05:31.96 UTC to 2020-11-15 15:05:31.96 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
4.4 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>.

Alberto Carrami��ana (INAOE) reports on behalf of the HAWC
collaboration (http://www.hawc-observatory.org/collaboration):

On 2020/11/14 15:05:32 UTC, the IceCube collaboration reported a 
track-like event with a high probability of 
being an astrophysical neutrino, IceCube-201114A. Location is at 
RA: 105.25 (+1.28/-1.12 deg  90% PSF containment) J2000
Dec:  6.05 (+0.95/-0.95 deg 90% PSF containment) J2000  
(GCN circular 28887
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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 June 2019. We searched
inside the reported IceCube error region. 
The most significant location, with p-value 2.80e-03 (6.31e-02 post-trials), 
is at RA 104.28 deg, Dec +6.58 deg (��0.14 deg 68% containment) J2000. 

We note that this position is inconsistent with the location of the Fermi-LAT
source 3FHL J0658.3+0636 / 4FGL J0658.6+0636.

We set a time-integrated 95% CL  upper limit on gamma rays at the 
maximum position of:

E^2 dN/dE = 2.59e-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 2020/11/13 12:35:15 UTC and ended
2020/11/15 12:52:30 UTC.
The most significant location, with p-value 4.02e-03 (8.94e-02 post-trials),
is at RA 106.22 deg, Dec +5.45 deg (��0.19 deg 68% containment) J2000.

We note that this position is inconsistent with the location of the Fermi-LAT
source 3FHL J0658.3+0636 / 4FGL J0658.6+0636.

We set a time-integrated 95% CL upper limit at the position of 
maximum significance of:

E^2 dN/dE = 8.73e-12 (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.

V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
J. Rodi (IAPS-Roma, Italy)
A. Coleiro (APC, France)
S. Mereghetti (INAF IASF-Milano, Italy)

on behalf of the INTEGRAL multi-messenger collaboration:
https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration

Using combination of INTEGRAL all-sky detectors (following [1]):
SPI/ACS, IBIS/Veto, and IBIS  we have performed a search for a prompt
gamma-ray counterpart of IceCube-201114A (GCN 28887
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 ).

At the time of the event (2020-11-14 15:05:31 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 73 deg with respect to the
spacecraft pointing axis. This orientation implies strongly suppressed
(24% of optimal) response of ISGRI, somewhat suppressed (42% of
optimal) response of IBIS/Veto, and near-optimal (87% of optimal)
response of SPI-ACS.

The background within +/-300 seconds around the event was stable 
(excess variance 1.2). 

We have performed a search for any impulsive events in INTEGRAL SPI-
ACS (as described in [2]), IBIS, and IBIS/Veto data.

We do not detect any significant counterparts and estimate a 3-sigma
upper limit on the 75-2000 keV fluence of 2.1e-07 erg/cm^2 (within the
50% probability containment region of the source localization) 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 ~1.8e-07 (6.7e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.

We report for completeness and in order of FAP, all excesses
identified in the search region. We find: 1 possibly associated
excess:

T-T0     | scale   | S/N | flux ( x 1e-06 erg/cm2/s)     | FAP    
-76.3    | 9.35    | 3.7 |    0.855 +/- 0.21   +/- 0.21   | 0.0411 

9 likely background excesses:

T-T0     | scale   | S/N | flux ( x 1e-06 erg/cm2/s)     | FAP    
-3.14    | 0.1     | 3.7 |    0.803 +/- 0.206  +/- 0.197  | 0.161 
20.6     | 0.15    | 4   |    0.724 +/- 0.168  +/- 0.178  | 0.43  
-6.14    | 0.1     | 3.3 |    0.717 +/- 0.206  +/- 0.176  | 0.712 
-95.7    | 0.05    | 6.5 |     2.05 +/- 0.3    +/- 0.505  | 0.714 
-287     | 1.95    | 3.7 |     1.95 +/- 0.462  +/- 0.479  | 0.761 
18.2     | 0.3     | 3.2 |     4.05 +/- 1.18   +/- 0.995  | 0.855 
-118     | 1.7     | 3.2 |     1.72 +/- 0.494  +/- 0.423  | 0.937 
16.8     | 0.15    | 3.4 |    0.609 +/- 0.168  +/- 0.15   | 0.963 
36       | 0.75    | 3.1 |     2.47 +/- 0.745  +/- 0.606  | 0.99  

Note that FAP estimates (especially at timescales above 2s) may be
possibly further affected by enhanced non-stationary local background
noise. This list excludes any excesses for which FAP is close to
unity.



All results quoted are preliminary.

This circular is an official product of the INTEGRAL Multi-Messenger
team.

[1] Savchenko et al. 2017, A&A 603, A46 
[2] Savchenko et al. 2012, A&A 541A, 122S

--

For the IceCube high-energy neutrino candidate event IceCube-201114A
(GCN 28887
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 ), at the event time Fermi-GBM was observing the reported
neutrino location at:

RA: 105.25 (+ 1.28 - 1.12  deg  90% PSF containment) J2000
Dec: 6.05 (+ 0.95 - 0.95 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-201114A.

We set upper limits on impulsive gamma-ray emission. Using the
representative soft, normal, and hard GRB-like templates described in
arXiv:1612.02395
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 , 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:    11.0     12.0     17.0
1.024 s:    7.7      7.1      6.7
8.192 s:    3.1      2.5      2.2

These results are preliminary.

D.F. Cowen (PSU), J. DeLaunay (PSU), D. B. Fox (PSU),
A. Keivani (Columbia U.), J.P. Osborne (U. Leicester),
F. Krauss (PSU), T. Gregoire (PSU), P.A. Evans (U. Leicester),
J.A. Kennea (PSU) and H. A. Ayala Solares (PSU) report:

Swift observed the field of IceCube 201114A (GCN Circ. 28887
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 ) between 16:50:06
2020 November 14 and 21:26:27 on 2020 November 14, collecting a total of 3.7 ks of
cleaned photon counting (PC) mode data. The observations used a 4-point tiling
pattern with a radius of ~0.3 degrees.

We found 2 X-ray sources, as detailed below. All of these are unknown but with
count rate consistent with the previous non-detections. We therefore do not
claim any of them as the likely counterpart to IceCube 201114A.

The 3-sigma upper limit in the field was in the range 8-10 x 10^-3 ct/sec.

The detected sources were:

Source no:   1
RA (J2000):  104.52092 [degrees] = 06h 58m 05.02s
Dec (J2000): +5.8679 [degrees] = +05d 52' 04.3"
Error:       +5.5 [arcsec, 90% conf. radius]
Count rate (0.3-10 keV): 4.1 (+3.9, -2.4) x 10-3 ct s-1
Flux (0.3-10 keV):       1.8 (+1.7, -1.0) x 10-13 erg cm-2 s-1


Source no:   2
RA (J2000):  104.92274 [degrees] = 06h 59m 41.46s
Dec (J2000): +5.7601 [degrees] = +05d 45' 36.4"
Error:       +6.6 [arcsec, 90% conf. radius]
Count rate (0.3-10 keV): 8 (+5, -3) x 10-3 ct s-1
Flux (0.3-10 keV):       3.3 (+2.1, -1.5) x 10-13 erg cm-2 s-1

Alexis Coleiro (APC/Universite de Paris) and Damien Dornic (CPPM/CNRS) on behalf of the ANTARES Collaboration. 

Using data from the ANTARES detector, we have performed a follow-up analysis of the recently reported single track-like event IceCube-201114A (GCN 28887
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  <https://gcn.gsfc.nasa.gov/gcn3/28887.gcn3
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 >). The reconstructed origin was -41 degrees below the horizon for ANTARES.

No up-going muon neutrino candidate events were recorded within 90% error box of the IceCube event during a +/- 1h time-window centered on the IceCube event time, and over which the potential source remained visible all time. This leads to a preliminary 90% confidence level upper limit on the muon-neutrino fluence from a point source of 19.2 GeV.cm^-2 over the energy range 4 TeV - 4 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 31.5 GeV.cm^-2 (685 GeV - 370 TeV) for an E^-2.5 spectrum. A search over an extended time window of +/- 1 day has also yielded no detection (47% visibility).
ANTARES <http://antares.in2p3.fr/> is the largest undersea neutrino detector (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:

On 20/11/14 at 15:05:31.96 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 threshold astrophysical neutrino purity for Gold alerts is 50% . This alert has an estimated false alarm rate of 0.92 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/134698_40735501.amon), more  
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 20/11/14
Time:  15:05:31.96 UT
RA: 105.25 (+ 1.28 - 1.12  deg  90% PSF containment) J2000
Dec: 6.05 (+ 0.95 - 0.95 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 is one Fermi 4FGL/3FHL source located within the 90% localization region, 4FGL J0658.6+0636, located at RA: 104.64 deg, Dec: 6.60 deg (J2000), at a distance of 0.81 deg 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