//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27787 SUBJECT: IceCube-200523A - IceCube observation of a high-energy neutrino candidate event DATE: 20/05/23 04:00:22 GMT FROM: Erik Blaufuss at U. Maryland/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 20/05/23 at 02:30:07.59 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 4.9 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/134116_58596690.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 20/05/23 Time: 02:30:07.59 UT RA: 338.64 (+10.77 -6.07 deg 90% PSF containment) J200 Dec: 1.75 (+1.84 -3.54 deg 90% PSF containment) J2000 The larger than usual error region in RA from the offline reconstructions is being investigated. We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. Ten sources from the Fermi 4FGL catalog are inside the 90% localization region, the closest being 4FGL J2227.9+0036 located at RA 336.98 deg and Dec 0.62 deg (at a distance of 2.01 degrees from the best-fit location). 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: 27788 SUBJECT: IceCube Alert 200523.10: Global MASTER-Net observations report DATE: 20/05/23 04:13:08 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, D. Cheryasov (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) started inspect of the IceCube Alert 200523.10 (trigger No 58596690,22h 35m 39.12s , +02d 08m 56.4s, R=1.56) errorbox 30 sec after notice time and 3994 sec after trigger time at 2020-05-23 03:36:42 UT, with upper limit up to 20.0 mag. The observations began at zenith distance = 41 deg. The sun altitude is -22.8 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) started inspect of the IceCube Alert 200523.10 errorbox 51 sec after notice time and 4015 sec after trigger time at 2020-05-23 03:37:03 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 62 deg. The sun altitude is -28.3 deg. The galactic latitude b = -46 deg., longitude l = 70 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1363593 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 4084 | 2020-05-23 03:36:42 | MASTER-SAAO | (22h 37m 53.79s , +02d 04m 34.7s) | C | 180 | 18.8 | 4084 | 2020-05-23 03:36:42 | MASTER-SAAO | (22h 30m 48.99s , +02d 03m 26.1s) | C | 180 | 19.7 | 4105 | 2020-05-23 03:37:03 | MASTER-IAC | (22h 34m 39.92s , +02d 03m 55.4s) | P| | 180 | 17.9 | 4285 | 2020-05-23 03:37:03 | MASTER-IAC | (22h 34m 39.92s , +02d 03m 55.4s) | P| | 540 | 18.5 | Coadd 4106 | 2020-05-23 03:37:03 | MASTER-IAC | (22h 33m 57.37s , +02d 07m 52.5s) | P- | 180 | 17.9 | 4286 | 2020-05-23 03:37:03 | MASTER-IAC | (22h 33m 57.38s , +02d 07m 52.5s) | P- | 540 | 18.5 | Coadd 4284 | 2020-05-23 03:40:01 | MASTER-SAAO | (22h 37m 57.53s , +02d 06m 16.8s) | C | 180 | 18.7 | 4284 | 2020-05-23 03:40:01 | MASTER-SAAO | (22h 30m 52.70s , +02d 05m 09.5s) | C | 180 | 20.0 | 4345 | 2020-05-23 03:41:02 | MASTER-IAC | (22h 34m 40.02s , +02d 04m 49.3s) | P| | 180 | 18.1 | 4345 | 2020-05-23 03:41:02 | MASTER-IAC | (22h 33m 57.53s , +02d 08m 48.6s) | P- | 180 | 18.1 | 4484 | 2020-05-23 03:43:21 | MASTER-SAAO | (22h 37m 50.72s , +02d 05m 15.0s) | C | 180 | 18.8 | 4484 | 2020-05-23 03:43:21 | MASTER-SAAO | (22h 30m 45.82s , +02d 04m 07.5s) | C | 180 | 20.0 | 4586 | 2020-05-23 03:45:03 | MASTER-IAC | (22h 34m 45.48s , +02d 03m 47.0s) | P| | 180 | 18.3 | 4586 | 2020-05-23 03:45:03 | MASTER-IAC | (22h 34m 02.92s , +02d 07m 48.0s) | P- | 180 | 18.1 | 4683 | 2020-05-23 03:46:40 | MASTER-SAAO | (22h 37m 51.02s , +02d 06m 09.5s) | C | 180 | 18.7 | 4683 | 2020-05-23 03:46:40 | MASTER-SAAO | (22h 30m 46.05s , +02d 05m 02.0s) | C | 180 | 20.0 | 4826 | 2020-05-23 03:49:03 | MASTER-IAC | (22h 34m 40.49s , +02d 02m 45.8s) | P| | 180 | 18.2 | 4826 | 2020-05-23 03:49:03 | MASTER-IAC | (22h 33m 57.90s , +02d 06m 48.0s) | P- | 180 | 18.1 | 4823 | 2020-05-23 03:50:00 | MASTER-SAAO | (22h 43m 08.73s , +01d 56m 16.9s) | C | 60 | 17.8 | 4823 | 2020-05-23 03:50:00 | MASTER-SAAO | (22h 36m 03.78s , +01d 55m 09.7s) | C | 60 | 19.7 | 5004 | 2020-05-23 03:53:01 | MASTER-IAC | (22h 42m 44.24s , -00d 06m 17.0s) | C | 60 | 17.8 | 5004 | 2020-05-23 03:53:01 | MASTER-IAC | (22h 34m 38.99s , -00d 01m 40.6s) | C | 60 | 18.1 | 5120 | 2020-05-23 03:54:57 | MASTER-SAAO | (22h 27m 10.69s , +01d 54m 39.4s) | C | 60 | 16.6 | 5123 | 2020-05-23 03:55:00 | MASTER-IAC | (22h 46m 01.40s , +03d 54m 53.1s) | C | 60 | 18.0 | 5217 | 2020-05-23 03:56:34 | MASTER-IAC | (22h 29m 59.27s , +03d 53m 39.9s) | C | 60 | 17.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27791 SUBJECT: IceCube-200523A: Upper limits from Fermi-GBM Observations DATE: 20/05/23 16:57:34 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 IceCube-200523A (GCN 27787), at the event time Fermi-GBM was observing the reported neutrino location at: RA: 338.64 (+10.77 -6.07 deg 90% PSF containment) J2000 Dee: 1.75 (+1.84 -3.54 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-200523A. We set upper limits on impulsive gamma-ray emission. Using the representative soft, normal, and hard GRB-like templates described in arXiv:1612.02395, 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: 6.5 9.5 17. 1.024 s: 2.2 2.9 6.1 8.192 s: 0.9 1.3 1.8 These results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27828 SUBJECT: IceCube-200523A: Upper limits from a search for additional neutrino events in IceCube DATE: 20/05/26 16:53:42 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-200523A (https://gcn.gsfc.nasa.gov/gcn3/27787.gcn3) in a time range of 2 days centered on the alert event time (2020-05-22 02:30:07.59 UTC to 2020-05-24 02:30:07.59 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, six additional track-like events are found in spatial coincidence with the 90% containment region of IceCube-200523A. 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 = 4.6 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 5 PeV. A subsequent search was performed to include the month of data prior to the alert event (2020-04-23 02:30:07.59 UTC to 2020-05-24 02:30:07.59 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 1.1 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.