//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29976 SUBJECT: IceCube-210510A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 21/05/10 07:50:58 GMT FROM: Marcos Santander at U. Alabama/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 21/05/10 at 04:50:10.73 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 3.944 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/135270_69188496.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 21/05/10 Time: 04:50:10.73 RA: 268.42 (+1.47, -1.60 deg 90% PSF containment) J2000 Dec: 3.81 (+0.68, -0.64 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 J1756.3+0236 at RA: 269.09 deg, Dec: 2.61 deg J2000 (1.37 deg away from the best-fit event position). 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: 29980 SUBJECT: IceCube-210510A: DDOTI Upper Limits DATE: 21/05/10 16:16:55 GMT FROM: Alan M Watson at UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Simone Dichiara (GSFC/UMD), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl Lopez (UNAM), Diego Gonzalez (UNAM), Margarita Pereyra (UNAM), Srihari Ravi (ASU), and Eleonora Troja (GSFC/UMD) report: We observed the field of the IceCube bronze event IceCube-210510A (IceCube Collaboration, GCN Circ. 29976) with the DDOTI wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) from 2021-05-10 05:44 to 11:33 UTC (0.9 to 6.7 hours after the trigger) and obtained 4.5 hours of exposure in the w filter. We observed a region covering aproximately 7 degrees in RA and 10 degrees in declination including the entire initial uncertainty region distributed in the GCN Notice and almost the entire updated 90% region (IceCube Collaboration, GCN Circ. 29976) except the small part west of RA = 269.80 degrees. We calibrated our images against the APASS catalog. Comparing to the Pan-STARRS DR1 catalog, we detect no uncataloged point sources to a 10-sigma limiting magnitude of w = 21.44. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29982 SUBJECT: IceCube Alert 210510.20: Global MASTER-Net observations report DATE: 21/05/10 20:39:15 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-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 Alert 210510.20 (trigger No 69188496,17h 51m 38.64s , +04d 00m 00.0s, R=0.51) errorbox 56237 sec after notice time and 56334 sec after trigger time at 2021-05-10 20:29:05 UT, with upper limit up to 15.3 mag. The observations began at zenith distance = 77 deg. The sun altitude is -58.2 deg. The galactic latitude b = 15 deg., longitude l = 30 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1610354 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 56425 | 2021-05-10 20:29:05 | MASTER-SAAO | (17h 51m 44.52s , +03d 53m 38.8s) | 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: 29995 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-210510A DATE: 21/05/11 21:23:18 GMT FROM: Simone Garrappa at DESY S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and C. C. Cheung (Naval Research Laboratory) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC210510A neutrino event (GCN 29976) 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 2021-05-10 at 04:50:10.73 UT (T0) with J2000 position RA = 268.42 (+1.47, -1.60) deg, Decl. = 3.81 (+0.68, -0.64) deg (90% PSF containment). One cataloged >100 MeV gamma-ray source is located within the 90% IC210510A localization region. This is 4FGL J1747.6+0324 (4FGL-DR2, The Fermi-LAT collaboration 2020, ApJS, 247, 33), of unknown association. Based on a preliminary analysis of the LAT data over the timescales of 1-day and 1-month prior to T0, this object is not significantly detected (> 5 sigma). 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 IC210510A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC210510A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 6.3e-10 ph cm^-2 s^-1 for ~12-years (2008-08-04 to 2021-05-10 UTC), and < 6.1e-9 (< 1.8e-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 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29999 SUBJECT: IceCube-210510A: No candidate counterparts from the Zwicky Transient Facility DATE: 21/05/12 14:35:29 GMT FROM: Robert Stein at DESY Robert Stein (DESY), Sven Weimann (Ruhr University Bochum), Jannis Necker (DESY), Simeon Reusch (DESY) and Anna Franckowiak (DESY/Ruhr University Bochum) report, On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: We observed the localization region of the neutrino event IceCube-210510A (Lagunas et. al, GCN 29980) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2021-05-10 at 09:56 UT, approximately 5.1 hours after event time. We covered 4.04 sq deg, corresponding to 100% of the reported localization region. This estimate does not account for chip gaps. Both initial exposures were 300s with a typical depth of 21.0 mag. We re-observed the localization area on 2021-05-11 and 2021-05-12 in the g-band with 30s exposure. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019; Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019). We looked for high-significance transient candidates with our pipeline, lying within the 90.0% localization of the skymap. No compelling candidate counterparts were detected. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the AMPEL Follow-up Pipeline (Stein et al. 2021). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30001 SUBJECT: IceCube-210510A: not observable by Fermi-GBM DATE: 21/05/12 16:00:50 GMT FROM: Joshua Wood at MSFC/Fermi-GBM C. Fletcher (USRA) reports on behalf of the Fermi-GBM team: For the IceCube high-energy neutrino candidate event IceCube-210510A (GCN 29976), the reported position: RA: 268.42 (+1.47, -1.60 deg 90% PSF containment) J2000 Dec: 3.81 (+0.68, -0.64 deg 90% PSF containment) J2000 was occulted by the Earth for Fermi-GBM from approximately 24.1 minutes prior until 10.4 minutes after event time. Therefore, the GBM observations are not constraining for prompt gamma-ray emission. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30003 SUBJECT: IceCube-210510A: Upper limits from a search for additional neutrino events in IceCube DATE: 21/05/12 18:34:47 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-210510A (https://gcn.gsfc.nasa.gov/gcn3/29454.gcn3) in a time range of 2 days centered on the alert event time (2021-05-09 04:50:10.73 UTC to 2021-05-11 04:50:10.73 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, one additional track-like event is found in spatial coincidence with the 90% containment region of IceCube-210510A. 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 = 3.3 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 (2021-04-10 04:50:10.73 UTC to 2021-05-11 04:50:10.73 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 3.9 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: 30376 SUBJECT: IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation DATE: 21/07/05 13:31:17 GMT FROM: Carlo Ferrigno at IAAT/ISDC 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: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using a 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-210510A (GCN 29976). At the time of the event (2021-05-10 04:50:10 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 93 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (11% of optimal) response of ISGRI, strongly suppressed (23% 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 rather stable (excess variance 1.3). We have performed a search for 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 2.6e-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 ~2.2e-07 (6.6e-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: 1 possibly associated excess: T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP 0.46 | 0.25 | 3.2 | 0.533 +/- 0.165 +/- 0.17 | 0.0252 6 likely background excesses: T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP -233 | 2.4 | 4 | 2.19 +/- 0.528 +/- 0.7 | 0.31 -42.9 | 1.85 | 3.2 | 2.01 +/- 0.601 +/- 0.64 | 0.345 91.5 | 0.25 | 5 | 0.829 +/- 0.165 +/- 0.264 | 0.565 2.36 | 0.05 | 3.1 | 1.16 +/- 0.372 +/- 0.37 | 0.718 92.7 | 0.3 | 4.3 | 0.661 +/- 0.151 +/- 0.211 | 0.722 -135 | 0.85 | 3.7 | 3.3 +/- 0.889 +/- 1.05 | 0.822 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