//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31842 SUBJECT: IceCube-220405B: No Candidate Counterparts from the Zwicky Transient Facility DATE: 22/04/06 15:32:43 GMT FROM: Jannis Necker at DESY Jannis Necker (DESY), Robert Stein (Caltech), Sven Weimann (Ruhr University Bochum), Simeon Reusch (DESY) and Anna Franckowiak (DESY/Ruhr University Bochum), On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2022), we observed the localization region of the neutrino event IceCube-220405B (Blaufuss et. al, GCN 31839) 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 2022-04-06 11:20 UTC, approximately 13 hours after event time. We covered 80.0% (2.8 sq deg) of the reported localization region. This estimate accounts for chip gaps. All exposures lasted 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, 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). No candidate counterparts were detected. ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France. 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: 31845 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-220405B DATE: 22/04/07 10:34:33 GMT FROM: Simone Garrappa at DESY S. Garrappa (DESY-Zeuthen) and S. Buson (Univ. of Wuerzburg) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC220405B neutrino event (GCN 31839) 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 2022-04-05 at  22:20:03.41  UT (T0) with J2000 position RA = +320.62 (+1.37, -1.13) deg, Decl. = 29.06 (+0.94, -0.68) deg (90% PSF containment). No cataloged gamma-ray (>100 MeV) sources are located within the 90% IC220405B localization region (4FGL-DR3; arXiv:2201.11184; The Fermi-LAT collaboration 2020, ApJS, 247, 33). 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 IC220405B best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC220405B best-fit position, the >100 MeV flux upper limit (95% confidence) is < 3.2e-10 ph cm^-2 s^-1 for ~13-years (2008-08-04 to 2022-04-05 UTC), and < 7.8e-9 (< 1.5e-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: 32004 SUBJECT: IceCube-220405B - ZTF19aavnpjv unrelated DATE: 22/05/06 15:26:08 GMT FROM: Jannis Necker at DESY Jannis Necker, Simeon Reusch (DESY), Jakob Nordin (HU Berlin), Vandad Fallah Ramazani (Ruhr-University Bochum), Anna Franckowiak (Ruhr-University Bochum / DESY) and Steve Schulze (University of Stockholm) report: We had identified ZTF19aavnpjv as a candidate counterpart during subsequent observations following the high-energy neutrino IceCube-220405B (GCN 31839). We observed ZTF19aavnpjv with the Nordic Optical Telescope (NOT) equipped with the ALFOSC spectrograph on May 3, 2022. Based on this spectrum, we classify ZTF19aavnpjv as a cataclysmic variable star. ZTF19aavnpjv is thus unrelated to the high-energy neutrino. This GCN is based on observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The data presented in this GCN were obtained with ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOT.