//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25225 SUBJECT: IceCube-190730A - IceCube observation of a high-energy neutrino candidate event DATE: 19/07/30 23:15:46 GMT FROM: Robert Stein at DESY The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 30 July 2019, at 20:50:41.31 UT, IceCube detected a track-like event with 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 0.68 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/132910_57145925.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2019/07/30 Time: 20:50:41.31 UT RA: 225.79 ( +1.28 -1.43 deg 90% PSF containment) J2000 Dec: + 10.47 ( +1.14 -0.89 deg 90% PSF containment) J2000 The Fermi-LAT catalogue source 4FGL J1504.4+1029, associated with the active galaxy PKS 1502+106, is located within the 50% uncertainty region of the event with an offset of 0.31 degrees from the best-fit neutrino location. PKS 1502+106 is an FSRQ at a redshift of 1.84 also listed in the 3FHL catalog of hard Fermi-LAT gamma-ray sources. Given the spatial coincidence with this FSRQ, and the high astrophysical neutrino signalness (approximately 67%), we strongly encourage follow-up observations of the neutrino region of interest and of the FSRQ in particular. 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: 25231 SUBJECT: IceCube-190730A: MASTER optical observation DATE: 19/07/31 07:24:46 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, A.Chasovnikov, D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), 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), D. Buckley (South African Astronomical Observatory), O. Gress, 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 Global Robotic Net ( http://observ.pereplet.ru, Lipunov et al., 2010,Advances in Astronomy, vol. 2010, 30L) observed IceCube-190730A (Stein et al. GCN 25225) in alert mode. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU,SAI Crimea astronomical station) was pointed to the IceCube Alert 190730.87 ( 15h 7m 19.25s , +10d 30m 28.08s, R=0.7552) errorbox 28 sec after notice time (62 sec after trigger time) at 2019-07-30 20:51:43 UT, with upper limit 18 mag. The observations began when error-box altitute = 22 deg, the sun altitude was -26.1 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory, Canarias) was pointed to the IceCube Alert 190730.87 errorbox 56 sec after notice time (89 sec after trigger time) at 2019-07-30 20:52:11 UT, with upper limit up to 20 mag. Observations started at twilight, began when error-box altitude = 65 deg, the sun altitude was -12.4 deg. The error-box galactic latitude b = -60 deg., longitude l = 98 deg. MASTER cover map is available http://master.sai.msu.ru/static/IC/MASTERcovermapofIC190730A.jpg AGNs and poss.OT analysis inside error box will be continued. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25232 SUBJECT: IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation DATE: 19/07/31 10:10:41 GMT FROM: Carlo Ferrigno at IAAT/ISDC C. Ferrigno, V. Savchenko (ISDC/UniGE, Switzerland) Maeve Doyle (UCD, Ireland), Alexander Lutovinov (IKI, Moscow, Russia) 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 the INTEGRAL all-sky detectors SPI/ACS (following [1]), IBIS/Veto, and IBIS, we have performed a search for a prompt gamma-ray counterpart of IceCube 190730A, a probable high-energy neutrino (GCN 25225). At the time of the event (2019-07-30 20:50:41 UTC, hereafter T0), INTEGRAL was operating in nominal mode. The most likely event localization was at an angle of 81 deg with respect to the spacecraft pointing axis. This orientation implies strongly suppressed (15% of optimal) response of ISGRI, strongly suppressed (31% of optimal) response of IBIS/Veto, and near-optimal (90% of optimal) response of SPI-ACS. The background within +/-300 seconds around the event was very stable (excess variance 1.1). However, we note the presence of excessive background variations in the hours surrounding the event, increasing the chance of spurious counterpart associations, and complicating the preliminary background estimation reported here. We have performed a search for impulsive events in INTEGRAL SPI-ACS (as described in [2]), IBIS, and IBIS/Veto data. We detect a moderately significant event (S/N 4.7) at 30s time scale at T0+10 s. The peak count rate (30s time scale) of the signal in SPI-ACS is 314 cts/s, which corresponds to 4.7e-8 erg/cm2/s in the 75-2000 keV energy range, assuming coordinates within the localization region and a typical long GRB spectrum (Band function with alpha=-1, beta=-2.5, and Ep=300 keV). This estimate does not account for uncertainties related to the unknown event spectrum, systematic uncertainty on the response (20%), or any dead-time correction. The non-detection of the event in IBIS would be compatible with a source at the location of the IceCube neutrino. We derive a preliminary estimate of the association False Alarm Probability (FAP) at the level of 0.046 (2 sigma), which suggests a likely random coincidence. Further analysis, taking into account accurate FAR measured on the basis of the study of the background during days surrounding the event will be reported elsewhere. Given the high chance of a random coincidence of the above event, we estimate a 3-sigma upper limit on the 75-2000 keV fluence of 1.8e-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 the typical long GRB spectrum used also above, the derived peak flux upper limit is ~1.6e-07 (5.4e-08) erg/cm^2/s at 1 s (8 s) time scale in 75-2000 keV energy range. From now on, we will report all the low-S/N excesses detected by our pipelines with preliminary FAP below unity, which are likely background fluctuations. In addition to the event described above, we find:       scale (s) | T-T0 (s) | S/N | flux ( x 1e-7 erg/cm2/s) |   FAP        0.25     | -6.6     | 3.1 | 4.11 +/-  1.22 +/-   1.1 | 0.433        0.95     |  101     | 3.5 | 2.31 +/- 0.625 +/- 0.618 | 0.785 In this list "flux" is the derived flux assuming a short-GRB typical spectrum with statistical and systematic uncertainties. Note that FAP estimates (especially at timescales above 2s) may be underestimated due to non-stationary local background noise. 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: 25233 SUBJECT: IceCube 190730A: not observable by Fermi-GBM DATE: 19/07/31 12:52:42 GMT FROM: Rachel Hamburg at UAH R. Hamburg (UAH) reports on behalf of the Fermi-GBM Team: For the IceCube high-energy neutrino candidate event 190730A (GCN 25225), the reported position: RA: 225.79 (+1.28 -1.43 deg 90% PSF containment) J2000 Dec: +10.47 (+1.14 -0.89 deg 90% PSF containment) J2000 was occulted by the Earth for Fermi-GBM from approximately 6 minutes prior until 30 minutes after event time. Therefore, the GBM observations are not constraining for prompt gamma-ray emission. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25238 SUBJECT: IceCube-190730A - HAWC follow-up DATE: 19/07/31 21:11:35 GMT FROM: Antonio Galvan at Inst.de Astronomia,UNAM Antonio Galvan (IA-UNAM), Israel Martinez-Castellanos (UMD) and Jose Andres Garcia-Gonzalez (IF-UNAM) reports on behalf of the HAWC collaboration ( http://www.hawc-observatory.org/collaboration/): On 2019-07-30 at 20:50:41.31 UTC, the IceCube collaboration reported a track-like event with a moderate probability of being of astrophysical origin, IceCube-190730A, at RA= 225.79 deg and Dec= +10.47 deg, J2000 (GCN circular 25225). In HAWC's sky, the neutrino was at zenith of 60.74 deg and outside of our field of view. We have performed a search in our archival data for a steady source as well as a transient source. * Search for a steady source in archival data from November 2014 to May 2018. Assuming a power law with a spectral index of -2.3 we searched in a 1.43 x 1.14 degree rectangle around IceCube's reported location. The highest significance, 2.38 sigma, was at RA= 226.54 deg, Dec= 10.35 deg (J2000). Note that there are at least 27 trials in this search, so post-trials significance is lower and equal to 0.712. We set a time-integrated upper limit 95% CL on the gamma-ray flux of E^2 dN/dE = 2.418e-13 (E/TeV)^-0.3 TeV cm^-2 s^-1. * Search for a transient source: Since the events was not in our field of view at the time reported on the GCN we did a search for the day before and after as well. The results are the following: 1.) 2019-07-29 Transit starts on 2019-07-29 22:00:36 and ends 2019-07-30 04:06:48 (UTC), 0.75 sigma pre-trials (0 post trials), was at RA= 225.64 deg, Dec= 9.86 deg (J2000). We set a time-integrated upper limit 95% CL on the gamma-ray flux of: E^2 dN/dE = 1.013e-11 (E/TeV)^-0.3 TeV cm^-2 s^-1. 2.) 2019-07-30 Transit starts on 2019-07-30 21:56:40 and ends 2019-07-31 04:02:52 (UTC), 1.76 sigma pre-trials (0 post trials), was at RA= 225.51 deg, Dec= 10.73 deg (J2000). We set a time-integrated upper limit 95% CL on the gamma-ray flux of: E^2 dN/dE = 1.251e-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: 25239 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-190730A DATE: 19/07/31 22:13:43 GMT FROM: Simone Garrappa at DESY S. Garrappa (DESY-Zeuthen, DE), S. Buson (Univ. of Wuerzburg, DE; UMBC, USA) and D. Gasparrini (ASI SSDC; INFN Roma Tor Vergata, IT), on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC190730A neutrino event (GCN 25225) 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 2019-07-30 20:50:41.31 UTC (T0) with J2000 position RA = 225.79 (-1.43,+1.28) deg, Decl. = +10.47 (-0.89,+1.14) deg 90% PSF containment. One cataloged >100 MeV gamma-ray source is located within the 90% IC190730A localization error, at a distance of roughly 0.3 deg. This is the object 4FGL J1504.4+1029 (The Fermi-LAT Collaboration 2019, arXiv:1902.10045) associated with the FSRQ PKS 1502+106. Based on a preliminary analysis of the LAT data over the-timescales of 1-day and 1-week prior to T0, this object is not significantly detected at gamma-rays. A preliminary light curve of the object is available at the FSSC (https://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/source/PKS_1502p106). We note that for multiple years PKS1502+106 has been among the top-ten highest-fluence blazars in the whole sky when the integrated long-term GeV gamma-ray flux is considered. After a long high-activity phase of about 4.5 years, its gamma-ray flux has slowly decreased over the past year and is currently much lower than what was observed in the previous 11 years of LAT monitoring. 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 IC190730A 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 < 1.9e-9 ph cm^-2 s^-1 for ~11-years (2008-08-04 / 2019-07-31 UTC), < 4.6e-9 (< 1.4e-8) ph cm^-2 s^-1 for a 1-month (1-week) 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 person 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: 25241 SUBJECT: IceCube-190730A: Upper limits from a search for additional neutrino events in IceCube DATE: 19/07/31 23:06:22 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-190730A (https://gcn.gsfc.nasa.gov/gcn3/25225.gcn3) in a time range of 2 days centered on the alert event time (2019-07-29 20:50:41.31 UTC to 2019-07-31 20:50:41.31 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% point spread function containment of IceCube-190730A. 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 at the alert position assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 3.8 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 approximately between 1 TeV and 2 PeV. A subsequent search was performed to include the previous month of data (2019-06-30 20:50:41.31 UTC to 2019-07-31 20:50:41.31 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 7.3 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: 25255 SUBJECT: IceCube 190730A: No counterpart candidates or blazar activity in GOTO observations DATE: 19/08/02 12:19:28 GMT FROM: Danny Steeghs at U.of Warwick/GOTO D.Steeghs(1), Y-L.Mong(2), G.Ramsay(5), L.Makrygianni(3), M.Kennedy(8), D.Galloway(2), K.Ulaczyk(1), J.Lyman(1), K.Ackley(2), A.Obradovic(2), M.Dyer(3), V.Dhillon(3), P.O'Brien(4), D.Pollacco(1), E.Thrane(2), S.Poshyachinda(6), E.Palle(7), K.Wiersema(1), R.Cutter(1), T. Marsh(1), R.West(1), B.Gompertz(1), E.Stanway(1), A.Casey(2), M.Brown(2), E.Rol(2), J.Mullaney(3), S.Littlefair(3), E.Daw(3), J.Maund(3), R.Starling(4), R.Eyles(4), S.Tooke(4), U.Sawangwit(6), D.Mkrtichian(6), S.Awiphan(6), S.Aukkaravittayapun(6), P.Irawati(6), R.Breton(8), D.Mata-Sanchez(8), T.Heikkila(9), R.Kotak(9), L.Nuttall (10) (1) Warwick University; (2) Monash University; (3) Univ. of Sheffield; (4) University of Leicester; (5) Armagh Observatory & Planetarium; (6) National Astronomical Research Institute of Thailand; (7) Instituto de Astrofisica de Canarias; (8) Univ. of Manchester; (9) University of Turku; (10) University of Portsmouth report on behalf of the GOTO collaboration: We carried out observations with the Gravitational-wave Optical Transient Observer (GOTO), in response to the 190730A IceCube neutrino event (GCN #25225, #25241). We obtained a series of 3x60s exposures using our wide L-band filter (400-700 nm) with four pointings covering the directional constraint reported in GCN #25225. Two sky passes have been completed so far, starting on 2019 July 31 21:16 UT and 2019 Aug 1 21:15 UT. Our mean 5-sigma detection limit was g=20.2 mag based on PS1 catalogue calibrators. Images are processed immediately after acquisition using the GOTOphoto pipeline. Difference imaging was performed on the median of each triplet of exposures using recent survey observations of the same pointings. Source candidates were initially filtered using a trained classifier and cross-matched against a variety of catalogs, including the MPC and PS1. Human candidate vetting was performed on those candidates identified by the classifier. The region was also visually inspected for any notable detections in case our classifier mis-scored a detection. No viable optical counterpart candidates were identified. We investigated the long-term behaviour of the FSRQ source PKS 1502+106 that was noted to be consistent with the directional constraints. Our sky survey coverage of this sources shows no notable signs of activity in recent months, including our recent epochs following the neutrino event. These findings are consistent with the ZTF coverage noted in Stein et al. 2019, ATEL 12974. Additional visits are planned, both scheduled and as part of the sky survey, to monitor any changes. ===== GOTO is operated at the La Palma observing facilities of the University of Warwick on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Portsmouth and the Instituto de Astrofisica de Canarias (IAC) (https://goto-observatory.org)