//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26276 SUBJECT: IceCube-191122A - IceCube observation of a high-energy neutrino candidate event DATE: 19/11/23 00:35:12 GMT FROM: Erik Blaufuss at U. Maryland/IceCube 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 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26280 SUBJECT: IceCube-191122A: Global MASTER-Net observations report DATE: 19/11/23 11:40:20 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs 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) 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 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26281 SUBJECT: IceCube-191122A: INTEGRAL was inactive at the time of the event DATE: 19/11/23 14:32:42 GMT FROM: James Rodi at IAPS-INAF 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26290 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-191122A DATE: 19/11/24 14:17:15 GMT FROM: Simone Garrappa at DESY 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) 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 ) and S. Buson (sara.buson atuni-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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26295 SUBJECT: IceCube-191122A: Upper limits from a search for additional neutrino events in IceCube DATE: 19/11/25 19:34:03 GMT FROM: Alex Pizzuto at ICECUBE/U of Wisconsin 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) 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26296 SUBJECT: IceCube-191122A: Not observable by Fermi-GBM DATE: 19/11/25 20:42:27 GMT FROM: Joshua Wood at MSFC/Fermi-GBM J. Wood (NASA/MSFC) reports on behalf of the Fermi-GBM Team: For the IceCube high-energy neutrino candidate event 191122A (GCN 26276), 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26298 SUBJECT: IceCube-191122A: No significant detection in HAWC DATE: 19/11/27 18:01:56 GMT FROM: Hugo Ayala at Pennsylvania State University 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 (GCN circular 26276). 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.