GCN Circular 34926

Swift-BAT/GUANO, IceCube, and GCN teams report:

The Swift-BAT/GUANO, IceCube, and GCN teams are pleased to announce the availability of new GCN notice types via the new GCN in JSON format.  JSON format notices can be streamed via Kafka (https://gcn.nasa.gov/quickstart). These new notice types are not available via GCN Classic.

Swift-BAT/GUANO: gcn.notices.swift.bat.guano (https://gcn.nasa.gov/missions/swift)
- Summary: GUANO is a ground-based analysis of data from Swift BAT, significantly enhancing the sensitivity and sky area covered as compared to Swift's onboard triggering.
- Occurence Rate: The Swift/BAT-GUANO notices occur at a rate of 50 times per year.
- Time Delay: The post-event processing and communication of alert is distributed to GCN within 10 minutes to 5 hours of detection, depending on data downlink method and space-to-ground communications resource availability.
- Notice Type: The new Swift/BAT-GUANO notice type (gcn.notices.swift.bat.guano) provides timestamps, sky locations, durations, and other supplementary information on gamma-ray transients discovered through this system, to enable prompt follow-up by observers and other instruments.  The 'initial' notice distributed for any detection will not include localization information. In the majority of cases later 'update' notices will follow with a localization attached. ~1/4 of GUANO bursts will have arcminute-scale localizations, distributed in the form [RA, Dec, Error] the remainder will be more poorly localized and may be distributed as HEALPix maps.

IceCube LVK Neutrino Track Search:gcn.notices.icecube.lvk_nu_track_search (https://gcn.nasa.gov/missions/icecube)
- Summary: IceCube is a is a cubic-kilometer Cherenkov particle detector deployed in the Antarctic ice beneath the Amundsen-Scott South Pole Station. IceCube detects neutrinos by observing the light produced by relativistic charged particles created by neutrino interactions in or near the instrumented volume of ice.
- Occurrence Rate: The LVK Nu Track Search notices are triggered by LIGO/Virgo/KAGRA alerts and occur at the same rate of these alerts, searching for neutrino signals from both significant and low significance LVK alerts.
- Time Delay: Neutrino searches are performed in a +/- 500 second time window about the LVK alert, and Nu Track search results are generally available within ~1000 seconds of the LVK GW event time.
- Notice Type: The new LVK Nu Track Search notice type (gcn.notices.icecube.lvk_nu_track_search) provides results from realtime searches for coincident neutrino signals from all LIGO/Virgo/KAGRA gravitational-wave alerts, using a realtime muon neutrino track-like event selection and the sky maps from gravitational wave detectors. Search results will include neutrino directions for observed coincident events with the aim to identify multi-messenger transient sources and seed electromagnetic followup up observations.

Notice Schema and Examples: The JSON schema defining the notice format and examples can be viewed in the Schema Browser (https://gcn.nasa.gov/docs/schema/stable/gcn/notices) or the GCN schema repository (https://github.com/nasa-gcn/gcn-schema).