GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- GRB 231111A: GECAM-C detection of a long burst
- GRB 231110A: GECAM detection
- GRB 231110A: GOTO optical upper limits
- GRB 231110A: SAO RAS optical observations
- GRB 231110A: Swift-XRT afterglow detection
- GRB231111A: YAHPT Observations
- GRB231111A: GIT confirmation of the optical afterglow
- GRB 231111A: MASTER OT earlier detection
- GRB 231111A: Nanshan/HMT optical observations
- GRB 231111A: Swift detection of a burst with an optical counterpart
- Swift GRB231111.60: Global MASTER-Net observations report
- GRB231110A: WFST Observation and upper limits
- Swift GRB231110.89: Global MASTER-Net observations report
- GRB 231110A: Swift detection of a burst
- LIGO/Virgo/KAGRA S231110g: Updated Sky localization
- LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
- GRB 231109A: Fermi GBM Final Localization
- IceCube-231103A: No candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S231108u: Updated Sky localization
- Fermi trigger No 721204446: Global MASTER-Net observations report
- Fermi GRB 231108A: Global MASTER-Net observations report
- GRB 231108A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA O4 Landscape
- LIGO/Virgo/KAGRA S231108u: Identification of a GW compact binary merger candidate
- GRB 231106A: AstroSat CZTI detection
- GRB 231106A: CALET Gamma-Ray Burst Monitor detection
- GRB 231104A: Swift-BAT refined analysis
- Fermi trigger No 721006392: Global MASTER-Net observations report
- Fermi Gamma-ray Burst Monitor trigger 231107654 / 721064512 is not a GRB
- GRB 231104A: FRAM-ORM optical limit
- LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
- Fermi GRB 231106A: Global MASTER-Net observations report
- GRB 231104A: Wendelstein Optical/Infrared Observations
- GRB 231104A: NuSTAR Observation of the prompt emission
- GRB 231106A: Fermi GBM Final Real-time Localization
- GRB 231104A: 3.6m DOT optical upper limit
- IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches
- Fermi-LAT gamma-ray observations of IceCube-231103A
- GRB 231104A: NOT upper limit
- GRB 231104A: Fermi GBM Observation
- GRB 231104B: Fermi GBM Final Real-time Localization
- Fermi GRB 231103A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231104ac: Updated Sky localization
- GRB 231104A: AKO Upper Limit
- GRB 231104A: AstroSat CZTI detection
- GRB 231104A: Swift-XRT refined Analysis
- GRB 231104A: Fermi-LAT detection
- LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
- GRB 231104A: Swift/UVOT Upper Limits
- GRB 231104A: Enhanced Swift-XRT position
- GRB231104A: LCOGT Optical Upper Limits
- GRB 231104A: Swift detection of a bright burst
- GRB 231104A: Fermi GBM Final Real-time Localization
- Swift GRB231104.07: Global MASTER-Net observations report
- IceCube Alert 231103.39: Global MASTER-Net observations report
- GRB 231103A: Fermi GBM Final Real-time Localization
- IceCube-231103A - IceCube observation of a high-energy neutrino candidate track-like event
- Fermi-LAT gamma-ray observations of IceCube-231027A
- LIGO/Virgo/KAGRA S231102w: Updated Sky localization
- LIGO/Virgo/KAGRA S231102i: Global MASTER-Net observations report
- GRB 231101A: Glowbug gamma-ray detection
- GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
- LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate
- New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
- Fermi trigger No 720498201: Global MASTER-Net observations report
- GRB 231101A: Fermi GBM Final Real-time Localization
- GRB 231030B: GRBAlpha detection
- GRB 231028B: VZLUSAT-2 detection
- Fermi trigger No 720415645: Global MASTER-Net observations report
- GRB 231030B: Fermi GBM Detection
- GRB 231030B: AstroSat CZTI detection
- Fermi GRB 231030B: Global MASTER-Net observations report
- IPN triangulation of GRB 231020A
- GRB 231030B: BALROG localization (Fermi Trigger 720388704 / GRB 231030832)
- GRB 231030B: Fermi GBM Final Real-time Localization
- GRB 231028A: Swift-BAT refined analysis
- IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231030av: Retraction of GW compact binary merger candidate
- GRB 231024A: AKO Optical Counterpart Candidate
- GRB 231028A: CALET Gamma-Ray Burst Monitor detection
- Fermi GRB 231030A: Global MASTER-Net observations report
- GRB 231030A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
- GRID detection of GRB 231020A
- LIGO/Virgo/KAGRA S231029k: Global MASTER-Net observations report
- GRB 231028A: AstroSat CZTI detection
- GRB 231028A: Glowbug gamma-ray detection
- GRB 231028A: Fermi GBM Detection
- Fermi trigger No 720224759: Global MASTER-Net observations report
- Swift GRB 231028A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231028bg: Updated Sky localization
- LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
- GRB 231028A: Swift detection of a burst
- GRB 231028A: Fermi GBM Final Real-time Localization
- IceCube Alert 231027.18: Global MASTER-Net observations report
- IceCube-231027A - IceCube observation of a high-energy neutrino candidate track-like event