GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"4055 results found.
- IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
- Fermi GBM Sub-Threshold Detection of GRB 260918A
- GRB 260918A: SVOM detection of a burst
- IceCube-260916A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
- IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260718A: SVOM detection of a burst
- IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
- IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
- IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260511A: UTGO H50 optical afterglow observation
- Fermi GBM Sub-Threshold Detection of GRB 260510B
- GRB 260510B: SVOM detection of a burst
- GRB 260509A: SVOM detection of a burst
- IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
- IPN triangulation of a bright burst from SGR 1E1841-045
- IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260425A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260410B: SVOM/GRM detection of a short faint burst
- EP260321a: Upper limits from a neutrino search with IceCube
- IceCube-260315A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
- Trigger 1442421: Swift detection of HMXB 1A 1118-61
- IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
- GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
- LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
- IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
- GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
- IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
- GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
- GRB 251208D: SVOM possible detection of a faint burst
- GRB 251203B : SVOM trigger sb25120304 is not a GRB
- IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
- LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
- LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
- LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
- LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
- LIGO/Virgo/KAGRA S251112cm: SOAR spectroscopy of three TROVE TNS candidates
- LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
- EP251118a: preliminary result of EP-FXT follow-up observation
- LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
- LIGO/Virgo/KAGRA S251117dq: Updated Sky localization
- LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
- LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
- LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
- LIGO/Virgo/KAGRA S251116en: Updated Sky localization
- LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
- LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
- LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
- LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
- LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume
- LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
- LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
- LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
- LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
- LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
- LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
- LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
- LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
- LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
- LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
- LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
- LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S251108fi: Updated Sky localization