//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24378 SUBJECT: IceCube-190503A - IceCube observation of a high-energy neutrino candidate event DATE: 19/05/03 20:51:47 GMT FROM: Erik Blaufuss at U. Maryland/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 19/05/03 at 17:23:08 UT IceCube detected a track-like, very-high-energy event with a high probability of being of astrophysical origin. The  event was identified by the Extremely High Energy (EHE) track event selection.  The IceCube detector was in a normal operating state.  EHE events typically have a neutrino interaction vertex that is outside the detector, produce a muon that traverses the detector volume, and have a high light level (a proxy for energy). After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon/42419327_132508.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 19/05/03 Time: 17:23:08.72 UT RA: 120.28 (+0.57 -0.77 deg  90% PSF containment) J2000 Dec: 6.35 (+0.76 -0.70 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% region. The nearest known gamma-ray source is 4FGL J0800.9+0733 at RA: 120.2262 deg, Dec: 7.5509 deg (1.2 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: 24381 SUBJECT: IceCube-190503A: INTEGRAL prompt observation DATE: 19/05/03 21:42:22 GMT FROM: James Rodi at IAPS-INAF James Rodi (IAPS-Roma, Italy), Sandro Mereghetti (INAF IASF-Milano, Italy) V. Savchenko, C. Ferrigno (ISDC/UniGE, Switzerland) A. Coleiro (APC, France) on behalf of the INTEGRAL multi-messenger collaboration: https://www.astro.unige.ch/cdci/integral-multimessenger-collaboration Using combination of INTEGRAL all-sky detectors (following Savchenko et al. 2017, A&A 603, A46): SPI/ACS, IBIS/Veto, and IBIS we have performed a search for a prompt gamma-ray counterpart of IceCube190503A (GCN 24378). At the time of the event (2019-05-03 17:23:08 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The peak of the event localization probability was at an angle of 170 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (3% of optimal) response of ISGRI, near-optimal (84% of optimal) response of IBIS/Veto, and strongly suppressed (38% of optimal) response of SPI-ACS. https://analyse.reproducible.online/transients/dashboard/event?utc=2019-... The background within +/-300 seconds around the event was very stable (excess variance 1.2).We have performed a search for any impulsive events in INTEGRAL SPI- ACS (as described in Savchenko et al. 2012, A&A 541A, 122S), 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 4e-07 erg/cm^2 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 ~4.1e-07 (9e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24384 SUBJECT: Fermi-GBM Observations of IceCube-190503A DATE: 19/05/04 02:03:59 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) and C.M. Hui (NASA/MSFC) report on behalf of the Fermi-GBM team: We have searched the Fermi Gamma-ray Burst Monitor data for a gamma-ray counterpart to IceCube-190503A (The IceCube Collaboration, GCN 24378). The neutrino position (RA, Dec) = (120.28, 6.35) was Earth-occulted for Fermi-GBM from about T0-650 s to T0+1500 s. We therefore cannot set any limits on impulsive emission. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24386 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-190503A DATE: 19/05/04 08:10:57 GMT FROM: Sara Buson at GSFC/Fermi S. Garrappa (DESY-Zeuthen, DE) and S. Buson (Univ. of Wuerzburg, DE; UMBC, USA) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC190503A neutrino event (GCN 24378) 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 2019-05-03 17:23:39 UT (T0) with J2000 position RA =120.28 (+0.57 -0.77) deg, Decl. = 6.35 (+0.76 -0.70) deg 90% PSF containment. No cataloged gamma-ray sources are found within the 90% IC190503A localization error. We searched for the existence of intermediate (months to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (>100 MeV) within the IC190503A 90% confidence localization. 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 < 1.3e-10 ph cm^-2 s^-1 for ~10.8-years (2008-08-04 / 2019-05-03), < 4.5e-9 ph cm^-2 s^-1 for a 1-month integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this source the Fermi-LAT contact persons are Simone Garrappa (simone.garrappa at desy.de) and Sara Buson (sara.buson at astro.uni-wuerzburg.edu). 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: 24388 SUBJECT: IceCube-190503A: Insight-HXMT/HE observation DATE: 19/05/04 14:04:14 GMT FROM: QiBin Yi at IHEP, HXMT Q. B. Yi, Q. Luo, C. Cai,S. Xiao , C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: Insight-HXMT was taking data normally around the HEN trigger time (T0=2019-05-03 17:23:08 UTC). At T0, about 100% of the LIGO localization region was covered by the Insight-HXMT without occultation by the Earth. Within T0 ± 100 s, no significant excess events (SNR > 3 sigma) are found in a search of the Insight-HXMT/HE raw light curves. Assuming the HEN counterpart GRB with three typical GRB Band spectral models, two typical duration timescales(1 s, 10 s) from the peak position of the LIGO-Virgo location probability map, the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are reported below: Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV): 1s: 1.8e-07 erg cm^-2 10s: 6.1e-07 erg cm^-2 Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV): 1s: 2.7e-07 erg cm^-2 10s: 9.7e-07 erg cm^-2 Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV): 1s: 4.6e-07 erg cm^-2 10s: 2.2e-06 erg cm^-2 Further analysis will be reported in the following circulars. All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (record energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was fundedjointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24394 SUBJECT: IceCube-190503A: Lick/KAIT Follow-Up Observations DATE: 19/05/05 06:39:31 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng, Keto Zhang, Sergiy Vasylyev and Alexei V. Filippenko (UC Berkeley) report on behalf of the Lick/KAIT follow-up team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to the IceCube neutrino candidate event IceCube-190503A (GCN 24378). We observed 54 galaxies within the IceCube error circle that were selected from the Glade catalog V1.0 (Dalya et al., 2018, MNRAS, 479, 2374; http://aquarius.elte.hu/glade/) according to their priority score and elevation visibility, with each clear-filter exposure time being 60 s. The first image was taken at 04:39:59, May 04 UT, about 11.3 hours after the trigger, and the last image at 05:45:42 UT. Template images were obtained next night on May 05 , 2019. The images were processed through the KAIT subtraction pipeline to search for potential optical counterparts. No viable transients were identified and the analysis is ongoing. Our typical limiting mag is 19.0. A full list of galaxies observed by KAIT is given below. GladeID UT(May 04) RA (J2000) Dec ----------------------------------------------- G0964222 04:39:59 08:01:55.870 +06:12:04.90 G0563204 04:41:08 08:02:24.720 +06:05:20.30 G0867044 04:42:18 08:01:54.010 +06:12:00.10 G1094027 04:43:27 08:03:08.020 +06:21:57.40 G1234036 04:44:34 08:01:41.170 +06:27:17.50 G0072770 04:45:44 08:02:36.450 +06:10:15.20 G0510454 04:46:53 08:01:12.160 +06:21:13.40 G1276512 04:48:02 08:01:52.520 +06:08:31.10 G1245750 04:49:12 08:02:27.870 +06:09:48.70 G0850227 04:50:21 08:02:07.260 +06:19:03.40 G0981133 04:51:30 08:01:57.910 +06:06:13.00 G0820621 04:52:40 08:03:46.290 +06:11:16.50 G1641637 04:53:53 08:01:06.850 +06:38:54.10 G1075330 04:55:02 08:02:40.480 +06:34:09.80 G1070846 04:56:12 08:03:03.850 +06:08:40.20 G0346609 04:57:21 08:03:33.130 +06:21:58.90 G0849480 04:58:30 08:00:39.680 +06:04:32.90 G0834707 04:59:40 08:01:11.220 +06:27:24.60 G0954061 05:00:49 08:01:45.990 +05:54:50.70 G1240435 05:01:58 08:01:10.160 +06:09:12.90 G0974364 05:03:07 08:00:58.540 +06:15:37.80 G0419170 05:04:17 08:03:30.550 +06:36:42.80 G1401952 05:05:26 08:00:19.530 +06:17:48.20 G0733806 05:06:35 08:02:44.780 +06:05:01.60 G0310669 05:07:45 08:01:03.260 +06:08:44.80 G0131957 05:08:54 08:01:58.690 +06:38:07.20 G1475382 05:10:03 08:03:52.140 +06:02:15.50 G1244242 05:11:12 08:01:08.860 +06:07:10.80 G1468878 05:12:22 08:03:50.260 +06:21:40.50 G1414455 05:13:31 08:00:42.320 +06:18:41.10 G0979388 05:19:08 08:02:48.490 +05:49:39.70 G0876280 05:20:17 08:00:39.770 +06:03:53.00 G0876660 05:21:27 08:01:03.590 +06:36:12.30 G0060787 05:22:36 08:01:59.900 +06:14:09.30 G0727667 05:23:45 08:03:23.750 +06:49:24.40 G1457750 05:24:54 08:04:46.510 +06:05:00.00 G0873736 05:26:04 08:02:38.190 +06:21:46.70 G1432060 05:27:11 08:01:35.880 +05:33:38.60 G0547403 05:28:20 08:02:40.000 +05:45:36.10 G1041891 05:29:30 07:59:35.620 +06:17:39.70 G0984639 05:30:39 08:03:05.920 +05:47:07.30 G1476499 05:31:48 08:04:22.590 +06:04:00.80 G0466629 05:32:58 08:04:47.810 +06:25:52.30 G0403378 05:34:07 08:00:14.490 +06:10:51.70 G0432549 05:35:14 08:00:28.690 +05:54:46.90 G1258519 05:36:28 08:01:26.230 +06:58:36.20 G0941209 05:37:37 08:03:06.160 +05:39:31.70 G0880361 05:38:47 08:00:36.230 +06:05:07.40 G0041485 05:39:56 08:03:03.350 +05:48:16.40 G0078389 05:41:05 08:00:08.890 +06:02:28.50 G0076618 05:42:14 07:59:55.390 +06:11:07.30 G0319796 05:43:24 08:01:46.280 +06:55:00.10 G0538304 05:44:33 08:04:17.120 +05:59:12.80 G1473979 05:45:42 08:04:48.350 +06:07:06.20 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24399 SUBJECT: IceCube-190503A: Insight-HXMT/HE observation DATE: 19/05/05 12:26:49 GMT FROM: QiBin Yi at IHEP, HXMT Q. B. Yi, Q. Luo, C. Cai, S. Xiao, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: Insight-HXMT was taking data normally around the trigger time (T0=2019-05-03 17:23:08 UTC) of this high-energy neutrino event (GCN 24381), which was monitored without any occultation by the Earth. Within T0 ± 100 s, no significant excess events (SNR > 3 sigma) are found in a search of the Insight-HXMT/HE raw light curves. Assuming the counterpart GRB with three typical GRB Band spectral models, two typical duration timescales(1 s, 10 s) coming from the position of this neutrion event, the 5-sigma upper-limits fluence (0.2 - 5 MeV, incident energy) are reported below: Band model 1 (alpha=-1.9, beta=-3.7, Ep=70 keV): 1s: 1.8e-07 erg cm^-2 10s: 6.1e-07 erg cm^-2 Band model 2 (alpha=-1.0, beta=-2.3, Ep=230 keV): 1s: 2.7e-07 erg cm^-2 10s: 9.7e-07 erg cm^-2 Band model 3 (alpha=-0.0, beta=-1.5, Ep=1000 keV): 1s: 4.6e-07 erg cm^-2 10s: 2.2e-06 erg cm^-2 Further analysis will be reported in the following circulars. All measurements above are made with the CsI detectors operating in the regular mode with the energy range of about 80-800 keV (record energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was fundedjointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24404 SUBJECT: IceCube-190503A: Swift-XRT Follow-up Observations DATE: 19/05/06 10:59:53 GMT FROM: Azadeh Keivani at Columbia U A. Keivani (Columbia U.), D. B. Fox (PSU), P. A. Evans (U. Leicester), J. A. Kennea (PSU), M. Santander (U. Alabama), & F. Krauss (GRAPPA/API, University of Amsterdam) report: The Neil Gehrels Swift Observatory observed the field of the IceCube EHE astrophysical neutrino candidate event IceCube-190503A (revision 1, https://gcn.gsfc.nasa.gov/gcn3/24378.gcn3) beginning May 3, 20:14:26 UT (2.85 hours after the neutrino arrival time). Swift utilized its onboard 19-point tiling pattern to cover a region centered on R.A., Dec. (J2000) = 120.28d, +6.35d, with a radius of approximately 0.8 deg; estimated 90%-containment radii for this event are 0.57 deg to 0.77 deg depending on position angle. Swift-XRT collected ~800 s per field of PC mode data per tile between 20:17:30 UT on 3 May and 10:51:09 UT on 4 May. Data have been reduced using the analysis approach and software routines of Evans et al. 2014 (ApJS, 210, 8). Several X-ray sources are detected in these observations, most of which are previously uncataloged and relatively low in flux, consistent with expectations for serendipitous (unrelated) sources over a region of this extent. A few sources with a false positive rate of ~1% look like real X-ray sources. However, none of them look promising to be IceCube-190503A counterparts due to their low flux and lack of variability. Excluding identified sources, the 3-sigma upper limit on the count rate of any point-like counterpart over the rest of the tiled region is 0.01 ct s^-1, which corresponds to a 0.3-10 keV flux of 4.0e-13 erg cm^-2 s^-1 for a typical AGN spectrum (nH=3e20 cm^-2, Gamma=1.7). Coordinates and count rates for the X-ray sources are provided below. Source, RA, Dec, Error_90 (arcsec), XRT count rate (ct s^-1) ------------------------------------------------------------------------------------------------------------- #1: 120.75962d, 7.01880d, 11.2, 1.0 (+0.5, -0.4) e-2 ------------------------------------------------------------------------------------------------------------- #2: 120.56238d, 6.63466d, 5.2, -- ------------------------------------------------------------------------------------------------------------- #3: 119.80197d, 7.11136d, 6.7, 1.1 (+0.6, -0.4) e-2 ------------------------------------------------------------------------------------------------------------- #4: 120.49133d, 6.05997d, 6.7, 9 (+6, -4) e-3 ------------------------------------------------------------------------------------------------------------- #5: 119.81789d, 6.45455d, 6.3, 1.0 (+0.5, -0.4) e-2 ------------------------------------------------------------------------------------------------------------- #6: 120.14345d, 6.13111d, 7.8, 4.6 (+4.4, -2.7) e-3 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24409 SUBJECT: Search for additional neutrino events from the direction of IceCube-190503A with IceCube DATE: 19/05/06 16:14:51 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-190503A (https://gcn.gsfc.nasa.gov/gcn3/24378.gcn3) in a time range of 2 days centered on the alert event time (2019-05-02 17:23:39 UTC to 2019-05-04 17:23:39 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% PSF containment of IceCube-190503A. We find that these data are well described by atmospheric background expectations, with a p-value of 1.0. Accordingly, these data would represent a time-integrated muon-neutrino flux upper limit assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 3.5 x 10^-5 TeV cm^-2 for this observation period. 90% of events IceCube would detect from a source at this declination with an E^-2 spectrum are between approximately 10 TeV and 3 PeV. A subsequent search was performed to include the previous month of data (2019-04-03 17:23:39 UTC to 2019-05-04 17:23:39 UTC). In this case, we also report a p-value of 1.0, consistent with no significant excess of track events, and a corresponding time-integrated muon-neutrino flux upper limit assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 6.7 x 10^-5 TeV cm^-2. 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.