//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27865 SUBJECT: IceCube-200530A - IceCube observation of a high-energy neutrino candidate event DATE: 20/05/30 13:22:56 GMT FROM: Robert Stein at DESY The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 20/05/30 at 07:54:29.43 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_GOLD alert stream. The threshold astrophysical neutrino purity for Gold alerts is 50%. This alert has an estimated false alarm rate of 1.952 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/134139_35473338.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 20/05/30 Time: 07:54:29.43 UT RA: 255.37 (+2.48 -2.56 deg 90% PSF containment) J2000 Dec: 26.61 (+2.33 -3.28 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 two Fermi 4FGL catalogue sources within the 90% contour, both lying close to the best fit position. The nearest is 4FGL J1702.2+2642, located 0.20 degrees from the best fit position. The other, 4FGL J1659.0+2627, is located 0.56 degrees from the best fit. 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: 27866 SUBJECT: IceCube-200530A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation DATE: 20/05/30 13:46:51 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: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using INTEGRAL/SPI-ACS realtime data (following [1]) we have performed a search for a prompt gamma-ray counterpart of IceCube-200530A (GCN 27865). At the time of the event (2020-05-30 07:54:29 UTC, hereafter T0), INTEGRAL instruments were operating in nominal mode. The peak of the event localization probability was at an angle of 64 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (23% of optimal) response of ISGRI, strongly suppressed (27% of optimal) response of IBIS/Veto, and near-optimal (68% 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]) data. We do not detect any significant counterparts and estimate a 3-sigma upper limit on the 75-2000 keV fluence of 2.7e-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 ~2.3e-07 (7.4e-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: 6 likely background excesses: T-T0 | scale | S/N | flux ( x 1e-06 erg/cm2/s) | FAP -2.15 | 0.95 | 3 | 2.81 +/- 0.844 +/- 0.657 | 0.0528 94.8 | 2.55 | 3.4 | 1.86 +/- 0.514 +/- 0.436 | 0.322 -82 | 3 | 3.2 | 1.75 +/- 0.474 +/- 0.409 | 0.424 -39.4 | 0.9 | 3.3 | 3.03 +/- 0.867 +/- 0.708 | 0.498 22.2 | 0.55 | 3.2 | 3.98 +/- 1.11 +/- 0.931 | 0.546 9.73 | 0.3 | 3.1 | 0.501 +/- 0.151 +/- 0.117 | 0.634 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: 27869 SUBJECT: IceCube Alert 200530.33: Global MASTER-Net observations report DATE: 20/05/30 17:13:08 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-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) started inspect of the IceCube Alert 200530.33 (trigger No 35473338,17h 01m 28.80s , +26d 36m 36.0s, R=2.67) errorbox 32838 sec after notice time and 32887 sec after trigger time at 2020-05-30 17:02:37 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 26 deg. The sun altitude is -15.2 deg. The galactic latitude b = 34 deg., longitude l = 48 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1369567 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 32918 | 2020-05-30 17:02:37 | MASTER-Amur | (16h 50m 00.36s , +28d 00m 08.3s) | C | 60 | 16.2 | 33057 | 2020-05-30 17:03:56 | MASTER-Amur | (17h 01m 06.96s , +26d 35m 43.9s) | C | 180 | 16.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27871 SUBJECT: IceCube-200530A: No ANTARES neutrino counterpart DATE: 20/05/31 08:00:43 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 single track-like event IceCube-200530A (GCN 27865< https://gcn.gsfc.nasa.gov/gcn3/27865.gcn3 >). The original reconstructed origin was on the edge of the ANTARES field of view for upward going events (-0.04 degrees below Its horizon).

No muon neutrino candidate events were recorded in a 3 deg cone centered on the location of the IceCube event coordinates (accounting for the reported uncertainties) during a +/- 1h time-window centered on the IceCube event time.

This leads to a preliminary conservative 90% confidence level upper limit on the muon-neutrino fluence from a point source of about 80 GeV.cm^-2 over the energy range 6.2 TeV – 6.0 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and about 110 GeV.cm^-2 (1.0 TeV - 560 TeV) for an E^-2.5 spectrum. A search over an extended time window of +/- 1 day has also yielded no detection (34% visibility).

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: 27872 SUBJECT: IceCube-200530A: Candidate Counterparts from the Zwicky Transient Facility DATE: 20/05/31 14:13:01 GMT FROM: Simeon Reusch at DESY Simeon Reusch, Robert Stein, Anna Franckowiak (DESY) and Suvi Gezari (UMD) 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-200530A (Stein et. al, GCN 27865) 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-band and r-band beginning at 2020-05-30T08:04:55.000 UTC, approximately 0.2 hours after event time. We covered 22.0 sq deg, corresponding to 98.9% of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. 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) 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 are left with the following high-significance transient candidates by our pipeline, all lying within the 90.0% localization of the skymap: +-----------------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | Notes | +-----------------------------------------------------------------------------------------+ | ZTF19aatubsj | SN 2019fdr | 257.2785777 | +26.8557286 | r | 19.43 | 0.11 | (a) | | ZTF20abbpkpa | AT 2020lam | 254.0980980 | +26.8138379 | r | 19.00 | 0.08 | (b) | | ZTF20abdnpdo | AT 2020lls | 257.5896488 | +24.4372389 | r | 19.94 | 0.18 | (c) | +-----------------------------------------------------------------------------------------+ (a) ZTF19aatubsj (SN 2019fdr) is a substantial long-duration flare in a Narrow-Line Seyfert 1 galaxy. The flare peaked roughly 300 days ago, but still remains significantly above pre-flare flux. (b) ZTF20abbpkpa (AT 2020lam) is a probable young supernova. It was first detected 6 days ago, at a magnitude of 19.6, but was not detected 2 days prior to a depth of 20.62. It has a SDSS spectroscopic z = 0.033, suggesting a current abs. magnitude of -16.7. (c) ZTF20abdnpdo (AT 2020lls) is also consistent with being a young supernova. SDSS photometric z is estimated at 0.052 +/- 0.012, which would result in a current abs. magnitude of -16.9. Spectroscopic follow-up of ZTF20abbpkpa and ZTF20abdnpdo is recommended. 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). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27873 SUBJECT: IceCube-200530A: No significant detection in HAWC DATE: 20/05/31 15:14:03 GMT FROM: Hugo Ayala at Pennsylvania State University Hugo Ayala (PSU) reports on behalf of the HAWC collaboration (http://www.hawc-observatory.org/collaboration): On 2020/05/20 07:54:29 UTC, the IceCube collaboration reported a track-like very-high-energy event that has a high probability of being an astrophysical neutrino, IceCube-200530A. Location is at RA: 255.37 (+2.48/-2.56 deg 90% PSF containment) J2000 Dec: 26.61 (+2.33/-3.28 deg 90% PSF containment) J2000 (GCN circular 27865). 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 May 2018. We searched inside the reported IceCube error region. The smallest p-value is 2.4e-3 (0.29 post-trials), is at RA 255.81 deg, Dec +24.62 deg (±0.14 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 = 3.09e-13 (E/TeV)^-0.3 TeV.cm^-2.s^-1 Search for a transient source. Since the IceCube event fall inside the HAWC field of view, we report on the result for the current transit of the IceCube position. Data acquisition started on 2020/05/29 09:59:32 UTC and ended 2020/05/30 10:18:26 UTC. The most significant location, with p-value 4.53e-03 (0.48 post-trials), is at RA 255.72 deg, Dec +24.05 deg (±0.22 deg 68% containment) J2000. We set a time-integrated 95% CL upper limit at the position of maximum significance of: E^2 dN/dE = 1.32e-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: 27875 SUBJECT: IceCube-200530A: not observable by Fermi-GBM DATE: 20/05/31 21:47:32 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-200530A (GCN 27865), the reported position: RA: 255.37 (+2.48 -2.56 deg 90% PSF containment) J2000 Dec: 26.61 (+2.33 -3.28 deg 90% PSF containment) J2000 was occulted by the Earth for Fermi-GBM from approximately from 24.4 minutes prior until 10.9 minutes after event time. Therefore, the GBM observations are not constraining for prompt gamma-ray emission. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27879 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-200530A DATE: 20/06/01 12:22:11 GMT FROM: Simone Garrappa at DESY S. Buson (Univ. of Wuerzburg) and S. Garrappa (DESY-Zeuthen) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC200530A neutrino event (GCN 27865) 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 2020-05-30 07:54:29.43 UT (T0) with J2000 position RA = 255.37 (+2.48, -2.56) deg, Decl. = 26.61 (+2.33, -3.28) deg 90% PSF containment. Two cataloged >100 MeV gamma-ray sources are located within the 90% IC200530A localization error. These are 4FGL J1702.2+2642 (associated with the BL Lac object MG2 J170210+2643) and 4FGL J1659.0+2627 (associated with the FSRQ 4C +26.51). 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 the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (>100 MeV) at the IC200530A 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 < 2.4e-10 ph cm^-2 s^-1 for ~11-years (2008-08-04 / 2020-05-30 UTC), < 1e-8 (< 1.7e-7) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. In the analysis of the ~11-years integrated LAT data (0.1 - 800 GeV), a 4.0 sigma new excess of gamma rays, Fermi J1707.0+2528 , was detected 1.7 deg offset from the best-fit IC200530A position and within the 90% confidence localization of the direction of the neutrino. Assuming a power-law spectrum, the best-fit localization is (J2000) RA: 256.77, Dec: 25.48 (12 arcmin 95% containment, 7 arcmin 68% containment). The gamma-ray best-fit spectral parameters are flux = (1.2+/-0.4)e-9 ph cm^-2 s^-1 and index = 2.2+/-0.2. In a preliminary analysis of the LAT data over 1-day and 1-month prior T0, Fermi J1707.0+2528 is not significantly detected in the LAT data. 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. Buson (sara.buson at uni-wuerzburg.de ) and S. Garrappa (simone.garrappa at desy.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: 27881 SUBJECT: IceCube-200530A: Upper limits from a search for additional neutrino events in IceCube DATE: 20/06/01 19:53:23 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-200530A (https://gcn.gsfc.nasa.gov/gcn3/27865.gcn3) in a time range of 2 days centered on the alert event time (2020-05-29 07:54:29.43 UTC to 2020-05-31 07:54:29.430 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero additional track-like events are found in spatial coincidence with the 90% containment region of IceCube-200530A. 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 1 PeV. A subsequent search was performed to include the month of data prior to the alert event (2020-04-30 07:54:29.43 UTC to 2020-05-31 07:54:29.430 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 1.0 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27910 SUBJECT: IceCube-200530A - SN2020lam classified as SN II without evidence of CSM interaction DATE: 20/06/09 09:56:37 GMT FROM: Simeon Reusch at DESY Simeon Reusch, Robert Stein, Anna Franckowiak (DESY), Jesper Sollerman, Tassilo Schweyer and Cristina Barbarino (Stockholm University) report: We observed ZTF candidate SN2020lam (Reusch et al, GCN 27872), a possible counterpart to high-energy neutrino IceCube-200530A (Stein et. al, GCN 27865), using the NOT/ALFOSC spectrograph on 6 June 2020. We classify SN2020lam as a Type II supernova with no signatures of interaction. Given the lack of evidence for a CSM-interaction neutrino production scenario, SN2020lam is likely unrelated to the high-energy IceCube neutrino IC200530A. AT2019fdr and AT2020lls remain source candidates. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27980 SUBJECT: IceCube-200530A - SN2020lls likely unrelated DATE: 20/06/18 13:53:49 GMT FROM: Simeon Reusch at DESY Simeon Reusch, Robert Stein, Anna Franckowiak, Jannis Necker (DESY), Jesper Sollerman, Cristina Barbarino and Tassilo Schweyer (Stockholm University) report: We observed ZTF candidate SN2020lls (Reusch et al, GCN 27872), a possible counterpart to high-energy neutrino IceCube-200530A (Stein et. al, GCN 27865), using the NOT/ALFOSC spectrograph on 12 June 2020. We classify SN2020lls as a Type Ic supernova without broad-line features. SN2020lls was detected with forced photometry by ZTF in i-band images 1 day prior to neutrino detection. An explosion time estimator puts the supernova explosion time 8 (+5/-2) days prior to neutrino detection. Both points suggest that the neutrino was detected several days after explosion.   The apparent delay between supernova explosion and neutrino detection is inconsistent with a choked-jet neutrino production scenario. Therefore, SN2020lls is likely not related to the high-energy IceCube neutrino IceCube-200530A. AT2019fdr remains a source candidate.