IceCube-190704A

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

On 19/07/04 at 18:48:52.25 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 1.00 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/gcn/notices_amon_g_b/132792_60166398.amon), more
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 19/07/04
Time: 18:48:52.25 UT
RA: 161.85 (+2.16 -4.33 deg  90% PSF containment) J2000
Dec: 27.11 (+1.81 -1.83  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 unassociated Fermi 4FGL source lying within the 50% uncertainty region, 4FGL J1049.8+2741, at RA: 162.46 deg, Dec: 27.68 deg (0.8 deg away from the best-fit event position). There are no other Fermi 3FHL or 4FGL catalogue sources within the 90% contour.

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>


_______________________________
Marcos Santander
Assistant Professor
Department of Physics & Astronomy
317B Gallalee Hall
University of Alabama
Tuscaloosa, AL 35487
+1 (205) 348 4863

R. Hamburg (UAH) reports on behalf of the Fermi-GBM Team:

At the time of the neutrino candidate IceCube-190704A
(GCN 24981
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 ), Fermi was passing through the South Atlantic
Anomaly from 6 minutes prior to 19 minutes after the trigger
time; therefore the GBM detectors were disabled.

Celia Sanchez-Fernandez (ESA ESAC, Madrid), James Rodi  (IAPS-Roma, Italy),
V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland)
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-190704A (GCN 24981
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 ).

At the time of the event (2019-07-04 18:48:52 UTC, hereafter T0),
INTEGRAL was operating in nominal mode. The peak of the event
localization probability was at an angle of 95 deg with respect to the
spacecraft pointing axis. This orientation implies strongly suppressed
(7.3% of optimal) response of ISGRI, strongly suppressed (26% of
optimal) response of IBIS/Veto, and near-optimal (82% of optimal)
response of SPI-ACS.

The background within +/-300 seconds around the event was very 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 2e-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 (5.8e-08)
erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range.



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

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-190704A (https://gcn.gsfc.nasa.gov/gcn3/24981.gcn3
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 ) in a time
range of 2 days centered on the alert event time (2019-07-03 18:48:52.25 UTC to 2019-07-05 18:48:52.25 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% point spread function containment of IceCube-190704A. We find that these data are well described
by atmospheric background expectations, with a p-value of 1.0. Accordingly, these data would
represent a time-integrated muon-neutrino flux upper limit at the alert position assuming an E^-2 spectrum (E^2
dN/dE) at the 90% CL of 5.1 x 10^-5 TeV cm^-2 for this observation period. 90% of events
IceCube would detect from a source at this declination with an E^-2 spectrum are
approximately between 1 TeV and 1 PeV.

A subsequent search was performed to include the previous month of data (2019-06-04 18:48:52.25 UTC to 2019-07-05 18:48:52.25 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
 1.4 x 10^-4 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>.

S. Garrappa (DESY-Zeuthen, DE), S. Buson (Univ. of Wuerzburg, DE; UMBC, USA) and T. Venters (NASA-GSFC, USA) on behalf of the Fermi-LAT collaboration:

We report an analysis of observations of the vicinity of the high-energy IC190704A neutrino event (GCN 24981
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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 2019-07-04 at 18:48:52.25 UTC (T0) with J2000 position RA = 161.85 (+2.16 -4.33) deg, Decl. = 27.11 (+1.81 -1.83) deg 90% PSF containment. 
One cataloged >0.1 MeV gamma-ray source is located within the 90% IC190704A localization error, at a distance of roughly 0.8 deg. This is the unassociated object 4FGL J1049.8+2741 (The Fermi-LAT collaboration, 2019, arXiv:1902.10045
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 ).  In a preliminary analysis of the LAT data over one day and one month prior T0, this object is not significantly detected  in the LAT data.
Preliminary analysis indicates no significant (>5sigma) excess emission (0.1 - 800 GeV) at the IC190704A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IceCube best-fit position, the >0.1 GeV flux upper limit (95% confidence) is <1.5e-10 ph cm^-2 s^-1 for ~10.9-years (2008-08-04 / 2019-07-05), < 6e-9 (< 5e-7) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. 
In the analysis of the 10.9-years integrated LAT data (0.1 - 800 GeV), a >5 sigma new excess of gamma rays was detected 0.8 deg offset from the best-fit IC190704 position and within the 90% confidence localization of the direction of the neutrino. Assuming a power-law spectrum, the best-fit localization is (J2000) RA:  161.343, Dec: 27.848 (0.08 deg 99% containment, 0.03 deg 68% containment). The most likely counterpart is the blazar 1WHSP J104516.2+275133 (a.k.a. Arsioli et al. 2015, A&A 579 34), located 0.025 deg away from the best-fit position of the gamma-ray excess, and within its 68% containment. The gamma-ray best-fit spectral parameters are flux = (7.8 +/- 3.5)e-10 ph cm^-2 s^-1 and index = 1.8 +/- 0.1. 

In a preliminary analysis of the LAT data over one day and one month prior T0, 1WHSP J104516.2+275133  is not significantly detected in the LAT data. The hard gamma-ray spectrum and detection of >100GeV photons positionally consistent with the blazar make this object a promising TeV candidate. We strongly encourage multiwavelength observations of this potentially compelling source, positionally consistent with the IceCube neutrino IC190704A.
Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source and of the neutrino region will continue. For this source the Fermi-LAT contact persons are S. Garrappa (simone.garrappa at desy.de <http://desy.de/>) and S. Buson (sara.buson at uni-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.

Q. B. Yi, C. Cai, Q. Luo, S. Xiao, Y. G. Zheng, 
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

Insight-HXMT was taking data normally around the trigger time
(T0=2019-07-04 18:48:52.25 UTC) of this high-energy neutrino event 
(GCN #24981
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 ), which was monitored without any occultation by 
the Earth. 

Within T0 +/- 100 s, no significant excess events (SNR > 3 sigma) 
are found in a search of the Insight-HXMT/HE raw light curves.

Assuming the counterpart GRB with three typical GRB Band spectral 
models, two typical duration timescales(1 s, 10 s) coming from the position
of this neutrino event, the 5-sigma upper-limits fluence 
(0.2 - 5 MeV, incident energy) are reported below:

Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV):
1s: 2.6e-07 erg cm^-2   
10s:5.0e-07 erg cm^-2 

Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV):
1s: 3.6e-07 erg cm^-2   
10s: 8.0e-07 erg cm^-2

Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV):
1s: 3.6e-07 erg cm^-2  
10s: 2.4e-06 erg cm^-2 

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.

Antonio Galv��n (IA-UNAM), Jos�� Andr��s Garc��a-Gonz��lez (IF-UNAM) and Israel
Martinez-Castellanos(UMD) reports on behalf of the HAWC collaboration (
http://www.hawc-observatory.org/collaboration/):


On 2019-07-04 at 18:48:52.25 UTC, the IceCube collaboration reported a
track-like event with a moderate probability of being of astrophysical
origin, IceCube-190704A, at RA 161.85 deg and Dec 27.11 deg, J2000 (GCN
circular 24981
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 ). In HAWC's sky, the neutrino was at zenith of 50.62  deg
and outside of our field of view. We have searched for a steady source as
well as a transient source.

* Search for a steady source in archival data from November 2014 to May
2018. Assuming a  power law with a spectral index of -2.3 we searched in a
4.08 degree circle around IceCube's reported location.

The highest significance, 2.75 sigma, was at RA= 162.47 deg, Dec= 26.28 deg
(J2000). Note that there are at least 250 trials in this search, so
post-trials significance is lower and equal to 0.65. We set a
time-integrated upper limit 95% CL on gamma rays of E^2 dN/dE = 2.52e-13
(E/TeV)^-2.3 TeV cm^-2 s^-1

* Search for a transient source: Since the events was not in our filed of
view at the time reported on the GCN we did a search for the day before as
well. The results are the following:

1.) 2019-07-03
Transit starts on 2019-07-03 19:17:59 and ends 2019-07-04 01:44:07 (UTC)

The highest significance, 4.06 sigma pre-trials (2.45 post trials), was at
RA= 161.67 deg, Dec= 26.80 deg (J2000). We set a time-integrated upper
limit 95% CL on gamma rays of: E^2 dN/dE = 1.98e-11 (E/TeV)^-2.3 TeV cm^-2
s^-1

2.) 2019-07-04
Transit starts on 2019-07-04 19:14:03 and ends 2019-07-05 01:40:11  (UTC)

The highest significance, 2.56 sigma pre-trials (zero post trials), was at
RA= 160.09 deg, Dec= 27.80 deg (J2000). We set a time-integrated upper
limit 95% CL on gamma rays of: E^2 dN/dE = 1.11e-11 (E/TeV)^-2.3 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.