//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31190 SUBJECT: IceCube Alert 211208.84: Global MASTER-Net observations report DATE: 21/12/08 20:39:17 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), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the IceCube Alert 211208.84 (trigger No 21306805,07h 35m 36.48s , +15d 41m 38.4s, R=0.51) errorbox 640 sec after notice time and 682 sec after trigger time at 2021-12-08 20:14:13 UT, with upper limit up to 15.8 mag. The observations began at zenith distance = 45 deg. The sun altitude is -28.1 deg. The galactic latitude b = 17 deg., longitude l = 204 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1808238 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 773 | 2021-12-08 20:14:13 | MASTER-Amur | (07h 34m 50.32s , +15d 18m 50.3s) | C | 180 | 15.8 | 773 | 2021-12-08 20:14:13 | MASTER-Amur | (07h 34m 23.36s , +15d 44m 19.3s) | C | 180 | 14.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31191 SUBJECT: IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 21/12/08 21:28:14 GMT FROM: Marcos Santander at U. Alabama/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2021-12-08 at 20:02:51.1 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 1.197 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/136015_21306805.amon, more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2021-12-08 Time: 20:02:51.1 UT RA: 114.52 (+2.82 -2.50 deg 90% PSF containment) J2000 Dec: 15.56 (+1.81 -1.39 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. Two gamma-ray sources listed in the 4FGL-DR2 Fermi-LAT catalog, 4FGL J0738.4+1539 and 4FGL J0743.1+1713, are located within the 90% error region for the event, located 0.1 and 2.1 deg away from the best-fit position, respectively. 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: 31193 SUBJECT: IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation DATE: 21/12/09 16:12:54 GMT FROM: Volodymyr Savchenko at ISDC,U of Geneve V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) J. Rodi (IAPS-Roma, Italy) A. Coleiro (APC, France) S. Mereghetti (INAF IASF-Milano, Italy) on behalf of the INTEGRAL multi-messenger 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-211208A (GCN 31191). At the time of the event (2021-12-08 20:02:51 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 75 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (24% of optimal) response of ISGRI, somewhat suppressed (40% of optimal) response of IBIS/Veto, and near-optimal (69% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was very stable (excess variance 1.1). 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 2.4e-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 ~2e-07 (6.7e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. We report for completeness and in order of FAP, all excesses identified in the search region. We find: 3 likely background excesses: T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP 231 | 9.35 | 3.9 | 0.922 +/- 0.254 +/- 0.247 | 0.0958 55.3 | 0.5 | 3.5 | 0.404 +/- 0.11 +/- 0.108 | 0.805 34.9 | 0.35 | 3.4 | 0.46 +/- 0.132 +/- 0.123 | 0.955 Note that FAP estimates (especially at timescales above 2s) may be possibly further affected by enhanced non-stationary local background noise. This list excludes any excesses for which FAP is close to unity. 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 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31194 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-211208A DATE: 21/12/09 20:26:24 GMT FROM: Simone Garrappa at DESY S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg), J. Sinapius (DESY-Zeuthen) and M. Kadler (Univ. of Wuerzburg) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC211208A neutrino event (GCN 31191) 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 2021-12-08 at 20:02:51.1 UT (T0) with J2000 position RA = 114.52 (+2.82, -2.50) deg, Decl. = 15.56 (+1.81, -1.39) deg (90% PSF containment). Two cataloged gamma-ray (>100 MeV) sources are located within the 90% IC211208A localization region (4FGL-DR2, The Fermi-LAT collaboration 2020, ApJS, 247, 33). These are 4FGL J0738.4+1539, associated with the radio source of unknown type NVSS J073824+153839 at 0.13 deg and 4FGL J0743.1+1713, associated with the BL Lac object TXS 0740+173 at 2.05 deg. Based on a preliminary analysis of LAT data at timescales of 1-month and 1-day prior to T0, these objects are not significantly detected (>5sigma). We searched for intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the IC211208A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC211208A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 3.0e-10 ph cm^-2 s^-1 for ~13-years (2008-08-04 to 2021-12-08 UTC), and < 4.5e-9 (< 7.0e-8) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. In the vicinity of the IC211208A best-fit position, outside the 90% localization region at 2.1 deg from the best-fit IC211208A localization, the cataloged >100 MeV gamma-ray source 4FGL J0738.1+1742 is significantly detected (> 5 sigma) integrating 1-day LAT data before T0. This source is associated with the BL Lac object PKS 0735+17 at z = 0.45 (Gattano et al, 2018 A&A, 618, A80). Preliminary analysis indicates that on 2021-12-08 the gamma-ray source was observed with a daily averaged flux (E>100 MeV) of (3+/-1) x 10^-7 photons cm^-2 s^-1 (statistical uncertainty only), about 5 times greater than the average flux reported in the fourth Fermi LAT source catalog (4FGL-DR2). The source was significantly detected at 1-day timescale on 2021-12-01 and was observed on 2021-12-04 with peak daily flux value of (5+/-2) x 10^-7 photons cm^-2 s^-1 (statistical uncertainty only), about 10 times greater than the average 4FGL-DR2 flux. The source was reported to be in optical brightening on 2021-11-08 and is currently at its brightest state in R band https://vo.astro.spbu.ru/sites/default/files/optic/pks0735R.png (see also ATel #15021). 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 gmail.com). 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: 31195 SUBJECT: IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube DATE: 21/12/10 02:37:44 GMT FROM: Marcos Santander at U. Alabama/IceCube 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-211208A (https://gcn.gsfc.nasa.gov/gcn3/31191.gcn3) in a time range of 1000 seconds centered on the alert event time (2021-12-08 19:54:31.100 UTC to 2021-12-08 20:11:11.100 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-211208A. 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-211208A is 1.4e-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 2e+02 GeV and 1e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2021-12-07 20:02:51.100 UTC to 2021-12-09 20:02:51.100 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-211208A 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) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31199 SUBJECT: IceCube-211208A: No significant detection in HAWC DATE: 21/12/10 20:39:57 GMT FROM: Hugo Ayala at Pennsylvania State University Hugo Ayala (Penn State) reports on behalf of the HAWC collaboration (http://www.hawc-observatory.org/collaboration): On 2021/12/08 20:02:51 UTC, the IceCube collaboration reported a track-like very-high-energy event that has a high probability of being an astrophysical neutrino, IceCube-211208A. Location is at RA: 114.52 (+2.82/-2.50 deg 90% PSF containment) J2000 Dec: 15.56 (+1.81/-1.39 deg 90% PSF containment) J2000 (GCN circular 31191). 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 June 2019. We searched inside the reported IceCube error region. The most significant location, with p-value 7.8e-3 (0.02 post-trials), is at RA 115.31 deg, Dec +14.52 deg (±0.13 deg 68% containment) J2000. We set a time-integrated 95% CL upper limit on gamma rays at the maximum position of: E^2 dN/dE = 2.27e-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 2021/12/07 11:57:44 UTC and ended 2021/12/09 12:17:24 UTC. The most significant location, with p-value 2.12e-3 (0.96 post-trials), is at RA 113.55 deg, Dec +17.23 deg (±0.18 deg 68% containment) J2000. We set a time-integrated 95% CL upper limit at the position of maximum significance of: E^2 dN/dE = 1.16e-11 (E/TeV)^-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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31225 SUBJECT: IceCube-211208A: No neutrino counterpart detected with ANTARES DATE: 21/12/13 08:38:46 GMT FROM: Antoine Kouchner at ANTARES Collaboration Alexis Coleiro (APC/Universite de Paris) and Damien Dornic (CPPM/CNRS) on behalf of the ANTARES Collaboration. Using data from the ANTARES detector, we have performed a follow-up analysis of the recently reported bronze track event IceCube-211208A (GCN#31191 ). The reconstructed origin was about 10 degrees above the horizon for ANTARES at the time of the alert. Extending slightly the analysis to include the events just above the horizon, no muon neutrino candidate events were recorded within the 90% error box of the IceCube event during a +/- 1h time-window centered on the IceCube event time. A search over an extended time window of +/- 1 day also yielded no detection (41% visibility). Over this time period, and restricting the search to the periods when the source remained below the horizon, this leads to a preliminary 90% confidence level upper limit on the muon-neutrino radiant fluence from a point source of about 17 GeV.cm^-2 over the energy range 5 TeV – 5 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 43 GeV.cm^-2 (1 - 500 TeV) for an E^-2.5 spectrum. ANTARES is the largest undersea neutrino detector (Mediterranean Sea) and it is primarily sensitive to astrophysical neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31529 SUBJECT: IceCube-211208A: the optical observation of the candidate PKS0735+178 DATE: 22/01/29 06:24:16 GMT FROM: Jirong Mao at Yunnan Obs D. R. Xiong, J. Mao, Y. Xin，D. H. Yan, J.-M. Bai (YNAO), and Y. L. Chang, W. Li, D. L. Xu (TDLI) report: We follow the IceCube-211208A alert (GCN circ. 31191), and we observe the BL Lac object PKS0735+178, which might be the source candidate of IceCube-211208A. We have performed the optical monitor in each night since 11, Dec. 2021. The 2.4-meter telescope and the BOOTES-4 telescope located at Gao-Mei-Gu (GMG) station of Yunnan Observatories are utilized for the multi-band photometry. We have obtained the very preliminary results. As an example, the magnitude of r=14.69 was measured from the observation in 11, Dec. 2021, and the the magnitude of r=15.60 was measured from the observation in 14, Jan. 2022. We note that the magnitude of r=15.50 is provided for this source by the Sloan Digital Sky Survey. The multi-band photometric monitor is ongoing. We are working on the careful data reduction. The long-term multi-wavelength observation for this target is encouraged. We acknowledge the support of the staff from the Lijiang GMG 2.4-m telescope and the BOOTES telescopes (A. J. Castro-Tirado and E. Fernandez- Garcia et al.).