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"35990 results found.
- GRB 231106A: Glowbug gamma-ray detection
- GRB 231111A: Xinglong-2.16m optical observations
- GRB 231110A: Swift-UVOT Upper Limits
- GRB 231111A: Afterglow redshift from OSIRIS+/GTC
- GRB 231104A: VZLUSAT-2 detection
- GRB 231111A: TNG tentative redshift
- GRB 231110A: Glowbug gamma-ray detection
- GRB 231110A: AstroSat CZTI detection
- GRB 231111A NUTTelA-TAO / BSTI Early Measurements
- GRB 231111A: Leavitt Observatory optical observations
- GRB231111A: Optical follow-up observations with Mephisto
- GRB 231111A: GMG observation (correction)
- GRB 231111A: GMG observation upper limit
- GRB 231106B: GRBAlpha detection
- GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
- GRB 231110A: Terskol Zeiss-2000 optical upper limit
- GRB 231111A: Swift-XRT refined Analysis
- GRB 231111A: Mondy optical observations
- GRB 231111A: GECAM-C detection of a long burst (correction)
- GRB 231110A: GECAM-B detection (correction)
- GRB 231111A: Enhanced Swift-XRT position
- 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
- GRB231110A: WFST Observation and upper limits
- GRB 231110A: Swift detection of a burst
- GRB 231109A: Fermi GBM Final Localization
- Fermi GRB 231108A: Global MASTER-Net observations report
- GRB 231108A: Fermi GBM Final Real-time Localization
- GRB 231106A: AstroSat CZTI detection
- GRB 231106A: CALET Gamma-Ray Burst Monitor detection
- GRB 231104A: Swift-BAT refined analysis
- 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
- 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
- GRB 231104A: AKO Upper Limit
- GRB 231104A: AstroSat CZTI detection
- GRB 231104A: Swift-XRT refined Analysis
- GRB 231104A: Fermi-LAT detection
- 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
- GRB 231103A: Fermi GBM Final Real-time Localization
- GRB 231101A: Glowbug gamma-ray detection
- GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
- GRB 231101A: Fermi GBM Final Real-time Localization
- GRB 231030B: GRBAlpha detection
- GRB 231028B: VZLUSAT-2 detection
- 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
- LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
- 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
- GRID detection of GRB 231020A
- GRB 231028A: AstroSat CZTI detection
- GRB 231028A: Glowbug gamma-ray detection
- GRB 231028A: Fermi GBM Detection
- Swift GRB 231028A: Global MASTER-Net observations report
- GRB 231028A: Swift detection of a burst
- GRB 231028A: Fermi GBM Final Real-time Localization
- GRB 231019A: Glowbug gamma-ray detection
- GRB 231025A: Fermi GBM Observation
- GRB 231024A: Fermi GBM Observation
- GRB 231025A: Swift/BAT-GUANO detection of a likely short burst
- GRB 231025A: Fermi GBM Final Localization
- GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
- GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
- GRB 231020A: AstroSat CZTI detection
- GRB 231020B: AstroSat CZTI detection
- GRB 231024A: GOTO optical counterpart candidate
- GRB 231024A: Fermi GBM Final Localization
- GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
- GRB 231020A: Fermi GBM Detection
- GRID detection of GRB 231004A