//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31650 SUBJECT: IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 22/02/25 15:44:29 GMT FROM: Marcos Santander at U. Alabama/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2022-02-25 at 14:12:00.7 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 2.329 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/136366_14203460.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2022-02-25 Time: 14:12:00.7 UT RA: 34.7 (+3.1/-2.6 deg 90% PSF containment) J2000 Dec: 0.0 (+1.8/-1.5 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. One gamma-ray source listed both in the 4FGL-DR2 and 3FHL Fermi-LAT catalogs is located in the 90% containment region for the event: 4FGL J0217.8+0144 (RA: 34.46 deg, Dec: 1.73 deg J2000, 1.75 deg from the best-fit alert position) associated with the quasar PKS 0215+015. 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: 31651 SUBJECT: IceCube Alert 220225.59: Global MASTER-Net observations report DATE: 22/02/25 22:39:26 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, T.Pogrosheva, E.Minkina, A.Chasovnikov, V.Topolev, V.Grinshpun, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), B.L.Carrasco, J.R.Valdes,V.Chavushyan, C.J.Martinez, V.M.Patino Alvarez, M.L.H.Rodriguez (INAOE, OAGH) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the IceCube Alert 220225.59 (trigger No 14203460,02h 15m 02.88s , -00d 11m 49.2s, R=2.02) errorbox 6700 sec after notice time and 6742 sec after trigger time at 2022-02-25 16:04:23 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 58 deg. The sun altitude is -13.6 deg. The galactic latitude b = -56 deg., longitude l = 164 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1894311 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 6833 | 2022-02-25 16:04:23 | MASTER-Kislovodsk | (02h 15m 10.26s , +00d 23m 09.9s) | C | 180 | 15.1 | 7038 | 2022-02-25 16:07:48 | MASTER-Kislovodsk | (02h 15m 13.62s , +00d 24m 27.2s) | C | 180 | 13.7 | 7250 | 2022-02-25 16:11:20 | MASTER-Kislovodsk | (02h 15m 07.96s , +00d 23m 37.5s) | C | 180 | 13.4 | 7403 | 2022-02-25 16:14:53 | MASTER-Kislovodsk | (02h 13m 14.49s , +03d 30m 33.1s) | C | 60 | 14.7 | 7484 | 2022-02-25 16:16:14 | MASTER-Kislovodsk | (02h 13m 10.23s , -00d 18m 34.4s) | C | 60 | 14.3 | 7564 | 2022-02-25 16:17:34 | MASTER-Kislovodsk | (02h 13m 03.20s , +01d 34m 23.3s) | C | 60 | 14.6 | 7644 | 2022-02-25 16:18:54 | MASTER-Kislovodsk | (02h 13m 26.40s , -02d 13m 36.2s) | C | 60 | 14.6 | 8331 | 2022-02-25 16:29:21 | MASTER-Kislovodsk | (02h 11m 27.68s , +00d 11m 30.0s) | C | 180 | 14.2 | 8471 | 2022-02-25 16:32:41 | MASTER-Kislovodsk | (02h 13m 23.54s , +03d 30m 15.0s) | C | 60 | 12.4 | 8611 | 2022-02-25 16:34:01 | MASTER-Kislovodsk | (02h 11m 32.91s , +00d 11m 14.9s) | C | 180 | 12.1 | 9895 | 2022-02-25 16:55:26 | MASTER-Kislovodsk | (02h 18m 20.71s , +02d 08m 22.6s) | C | 180 | 16.5 | 13552 | 2022-02-25 17:56:22 | MASTER-Kislovodsk | (02h 18m 22.06s , +02d 06m 48.2s) | C | 180 | 16.0 | 15122 | 2022-02-25 18:22:32 | MASTER-Kislovodsk | (02h 15m 34.58s , +00d 19m 13.7s) | C | 180 | 15.4 | 15323 | 2022-02-25 18:25:53 | MASTER-Kislovodsk | (02h 15m 38.52s , +00d 20m 36.8s) | C | 180 | 14.5 | 15659 | 2022-02-25 18:31:29 | MASTER-Kislovodsk | (02h 15m 30.04s , +02d 20m 34.3s) | C | 180 | 15.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31653 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-220225A DATE: 22/02/26 01:39:33 GMT FROM: Simone Garrappa at DESY S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg), C. C. Cheung (Naval Research Laboratory) and J. Sinapius (DESY-Zeuthen) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy neutrino event IC220225A (GCN 31650) 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 2022-02-25 14:12:00.7 UTC (T0) with J2000 position RA = 34.7 (+3.1, -2.6) deg, Dec = 0.0 (+1.8, -1.5) deg (90% PSF containment). Two cataloged >100 MeV gamma-ray sources are located within the 90% IC220225A localization error (The Fourth Fermi-LAT catalog, 4FGL-DR3; The Fermi-LAT collaboration 2022, arXiv:2201.11184). These are 4FGL J0217.8+0144, located ~1.75 deg from the neutrino best-fit position and associated with the flat-spectrum radio quasar PKS 0215+015 located at z = 1.715 (Foltz & Chaffee 1987, AJ, 93, 529) and 4FGL J0208.5-0046, located ~2.7 deg from the neutrino best-fit position and associated with the BL Lac object PKS 0205-010 with an uncertain SDSS-based redshift (Richards et al. 2004, ApJS, 155, 258; Richards et al. 2009, ApJS, 180, 67). Based on a preliminary analysis of the LAT data over a 1-day and 1-month integration time before T0, 4FGL J0208.5-0046 is not significantly detected at gamma rays. 4FGL J0217.8+0144 has been in an enhanced gamma-ray activity state since mid-2021.  Preliminary analysis of the 1-day interval preceding T0 indicates that the source is in a high state with flux (E>100 MeV) of (3+/-1) x 10^-7 photons cm^-2 s^-1 (integrated before T0, statistical uncertainty only) and power-law index 2.3 +/- 0.3. This flux is more than 7 times greater than the average flux reported in the 4FGL-DR3 catalog. Averaged over the month preceding T0, the flux (E>100 MeV) is (1.6+/-0.2) x 10^-7 photons cm^-2 s^-1 (statistical uncertainty only), more than 3 times greater than the average flux reported in the 4FGL-DR3 catalog, and the power-law index is 2.1 +/- 0.1 . The gamma-ray spectral indices of the flaring state are consistent with the value reported in the latest 4FGL-DR3 catalog (index = 2.21 +/- 0.02). A preliminary light curve can be accessed via the Fermi-LAT Light-Curve Repository at https://fermi.gsfc.nasa.gov/ssc/data/access/lat/LightCurveRepository/source.php?source_name=4FGL_J0217.8+0144. 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) at the the IC220225A best-fit position. 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 < 2.5 x 10^-10 ph cm^-2 s^-1 for ~13-years (2008-08-04 / 2022-02-25 UTC), < 1.0x 10^-8 (< 1.1 x 10^-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 region 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). We encourage multifrequency observations of these sources. 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: 31656 SUBJECT: IceCube-220225A: Upper limits from a search for additional neutrino events in IceCube DATE: 22/02/28 17:10:31 GMT FROM: Alex Pizzuto at ICECUBE/U of Wisconsin The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-220225A (https://gcn.gsfc.nasa.gov/gcn3/31650.gcn3) in a time range of 1000 seconds centered on the alert event time (2022-02-25 14:03:40.685 UTC to 2022-02-25 14:20:20.685 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-220225A. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-220225A ranges from 1.4e-01 to 1.5e-01 GeV cm^-2 in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 3e+02 GeV and 2e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2022-02-24 14:12:00.685 UTC to 2022-02-26 14:12:00.685 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-220225A is 1.6e-01 GeV cm^-2 in a 2 day time window. 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. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021)