//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30152 SUBJECT: IceCube Alert 210608.15: Global MASTER-Net observations report DATE: 21/06/08 06:13:08 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), 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the IceCube Alert 210608.15 (trigger No 69917294,22h 28m 04.32s , +18d 38m 49.2s, R=1.31) errorbox 6843 sec after notice time and 6874 sec after trigger time at 2021-06-08 05:35:35 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 78 deg. The sun altitude is -74.0 deg. The galactic latitude b = -33 deg., longitude l = 83 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1631004 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 6905 | 2021-06-08 05:35:35 | MASTER-OAFA | (22h 28m 56.85s , +15d 35m 59.9s) | C | 60 | 15.4 | 6984 | 2021-06-08 05:36:55 | MASTER-OAFA | (22h 18m 32.02s , +17d 30m 17.3s) | C | 60 | 16.7 | 7469 | 2021-06-08 05:45:00 | MASTER-OAFA | (22h 18m 01.88s , +19d 24m 09.8s) | C | 60 | 17.1 | 7549 | 2021-06-08 05:46:19 | MASTER-OAFA | (22h 26m 29.43s , +19d 25m 15.7s) | C | 60 | 16.4 | 7913 | 2021-06-08 05:52:23 | MASTER-OAFA | (22h 28m 50.14s , +15d 36m 44.2s) | C | 60 | 17.2 | 7992 | 2021-06-08 05:53:43 | MASTER-OAFA | (22h 18m 28.78s , +17d 31m 56.4s) | C | 60 | 17.8 | 8072 | 2021-06-08 05:55:02 | MASTER-OAFA | (22h 27m 00.31s , +17d 30m 50.7s) | C | 60 | 17.5 | 8560 | 2021-06-08 06:03:11 | MASTER-OAFA | (22h 17m 57.42s , +19d 24m 07.1s) | C | 60 | 18.0 | 8640 | 2021-06-08 06:04:30 | MASTER-OAFA | (22h 26m 31.07s , +19d 25m 39.3s) | C | 60 | 17.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30153 SUBJECT: IceCube-210608A: IceCube observation of a high-energy neutrino candidate track-like event DATE: 21/06/08 07:12:18 GMT FROM: Cristina Lagunas Gualda at DESY The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 8 June 2021 at 03:41:00.98 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 3.075 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/135363_69917294.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 8 June 2021 Time: 03:41:00.98 UT RA: 337.41 (+4.89 -11.64 deg 90% PSF containment) J2000 Dec: +18.37 (+3.75 -3.24 deg 90% PSF containment) J2000 Due to the topology of this event, with a short distance traversed through the detector, the updated angular uncertainty is significantly larger than average error contours. We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. There are several Fermi-LAT 4FGL sources inside the 90% localization region. The closest source is 4FGL J2235.3+1818 located at 338.84 deg and Dec 18.31 deg (J2000), at a distance of 1.35 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: 30155 SUBJECT: IceCube-210608A: not observable by Fermi-GBM DATE: 21/06/08 20:41:48 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) reports on behalf of the Fermi-GBM team: For the IceCube high-energy neutrino candidate event IceCube-210608A (GCN 30153), the reported position: RA: 337.41 (+4.89 -11.64 deg 90% PSF containment) J2000 Dec: +18.37 (+3.75 -3.24 deg 90% PSF containment) J2000 was occulted by the Earth for Fermi-GBM from approximately 6.3 minutes prior until 29.4 minutes after event time. Therefore, the GBM observations are not constraining for prompt gamma-ray emission. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30156 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-210608A DATE: 21/06/08 21:17:17 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 IC210608A neutrino event (GCN 30153) 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 2021-06-08 at 03:41:00.98 UT (T0) with J2000 position RA = 337.41 (+4.89, -11.64) deg, Decl. = 18.37 (+3.75, -3.24) deg (90% PSF containment). Fifteen cataloged gamma-ray (>100 MeV) sources are located within the 90% IC210608A localization region (4FGL-DR2, The Fermi-LAT collaboration 2020, ApJS, 247, 33). Based on a preliminary analysis of the LAT data over the timescale of 1-day prior to T0, none of these objects is significantly detected (> 5 sigma). We searched for intermediate (days to month) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the IC210608A best-fit position.  Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC210608A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 5.4e-9 (< 9.6e-8) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. Based on a preliminary analysis, the cataloged object 4FGL J2243.9+2021 is significantly (> 5 sigma) detected in a 1-month integration time before T0. The source is associated with the RGB J2243+203 (Laurent-Muehleisen, S. A. et al. 1999, ApJ, 525, 127), a very-high-energy (>100GeV) BL Lac object located at unknown redshift (Abeysekara, A. U. et al. 2017, ApJS, 233, 7). It is detected with flux (>100 MeV) = (4 +/- 1)e-08 ph cm^-2 s^-1, consistent with the 4FGL catalog value, and power-law index = 1.9 +/- 0.2, consistent with the 4FGL value of 1.85 +/- 0.02. The source has not shown enhanced activity within the past year, and it is not significantly detected on a timescale of 1-day before T0. 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.