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.
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 161004A: RATIR Optical and NIR Observations
- GRB 160917B: Lomonosov BDRG gamma ray discovery
- GRB 161004B: Enhanced Swift-XRT position
- GRB 160917A: Lomonosov BDRG gamma ray detection
- GRB 160915A: Lomonosov BDRG gamma ray detection
- GRB 161004B: Prompt enhanced Swift-XRT position
- GRB 161004B: Swift detection of a burst
- GRB 161004A: SAO RAS optical upper limit
- GRB 161004A: Swift-XRT refined Analysis
- GRB 161004A: Swift/UVOT Detection
- GRB 161004A: Enhanced Swift-XRT position
- Swift Trigger 715209 is not an astrophysical event
- GRB 161004A: Bassano Bresciano Observatory upper limit
- GRB 161004A: TSHAO optical observations
- GRB 161004A: Swift detection of a burst with a possible optical counterpart
- GRB 160927A: 15 GHz upper limits from AMI
- Konus-Wind observation of GRB 161001A (short/hard ?)
- GRB 161001A: MASTER-OAFA and MASTER-SAAO early optical observations
- GRB 161001A: GROND afterglow candidate
- GRB 161001A, Swift-BAT refined analysis (likely a short GRB)
- GRB 161001A: Fermi GBM detection
- GRB 161001A: Swift-XRT refined Analysis
- GRB 161001A: X-shooter spectroscopy, candidate host galaxy and redshift
- GRB 161001A: Swift/UVOT Upper Limits
- GRB 161001A: Enhanced Swift-XRT position
- GRB 161001A: Prompt enhanced Swift-XRT position
- GRB 161001A: Swift detection of a burst
- Possible radio detection of GRB 160910A with the GMRT
- Fermi GBM trigger 496791348/160928900 is not a GRB
- GRB 160927A: Magellan imaging
- GRB 160927A: Swift/UVOT Upper Limits
- GRB 160927A: Bassano Bresciano Observatory optical upper limit
- GRB 160927A: Swift-BAT refined analysis
- GRB 160927A: NOT optical observations
- GRB 160927A: GROND Observations
- GRB 160927A: Swift-XRT refined Analysis
- GRB 160927A: Enhanced Swift-XRT position
- GRB 160927A: TNG optical afterglow confirmation
- GRB160927A: D50 optical limit
- GRB 160927A: RTT150 optical afterglow candidate
- GRB 160927A: Prompt enhanced Swift-XRT position
- GRB 160927A: Swift detection of a short hard burst
- GRB 160917A: 15 GHz upper limits from AMI
- GRB 160912A: 15 GHz upper limits from AMI
- GRB160910A: AstroSat CZTI detection
- XRT refined analysis for GRB 160925A
- GRB 160925A/MASTER optical transient: Mondy optical observations
- GRB 160925A: MITSuME Akeno Optical Observations
- GRB 160925A: Bassano Bresciano Photometry of MASTER optical transient
- GRB 160925A: Optical spectroscopy of MASTER optical transient
- GRB160824B: AstroSat CZTI detection
- GRB160917A: AstroSat CZTI detection
- GRB 160925A / Fermi 496473540: MASTER OT observations
- GRB 160925A: Swift ToO observations
- GRB160925A / Fermi 496473540: MASTER optical transient confirmation by LCOGT-FTN
- GRB 160925A / Fermi 496473540: Global MASTER Net OT discovery
- GRB 160910A: 15 GHz detection from AMI
- GRB 160917A: Mondy afterglow confirmation
- GRB 160910A: TSHAO optical observations
- GRB 160917A: Swift-BAT refined analysis
- GRB 160917A: RATIR Optical and NIR Observations
- GRB 160917A: Fermi GBM observation
- GRB 160917A: Swift/UVOT Detection
- GRB 160917A: Swift-XRT refined Analysis
- GRB 160917A: Mondy optical observations
- GRB 160917A: OSN I-band upper limits
- GRB 160917A: Enhanced Swift-XRT position
- GRB 160917A: Swift detection of a burst
- GRB 160910A: Maidanak optical observations
- GRB 160912A, Swift-BAT refined analysis
- GRB 160910A: Swift/UVOT Detection
- GRB 160912A: RATIR Optical and NIR Observations
- GRB 160912A: Swift/UVOT Weak Afterglow Detection
- GRB 160912A: Mondy optical observations
- GRB 160910A: Mondy optical observations
- GRB 160912A Liverpool Telescope optical afterglow
- GRB 160912A: Swift-XRT refined Analysis
- GRB 160912A: Fermi GBM detection
- GRB 160912A: Enhanced Swift-XRT position
- GRB 160910A: Global MASTER Net OT detection before LAT alert
- Konus-Wind observation of GRB 160910A
- GRB 160912A: Swift detection of a burst
- GRB 160910A: Correction to GCN 19904
- GRB 160910A: XRT results and corrections to GCN 19905 & 19906
- GRB 160910A: CALET Gamma-Ray Burst Monitor detection
- GRB 160910A: NOT afterglow confirmation
- GRB 160910A: Afterglow detection from OSN
- GRB 160910A: Tiled Swift observations
- GRB 160910A: Swift-XRT afterglow detection
- GRB 160908A: CALET Gamma-Ray Burst Monitor detection
- GRB 160910A: Fermi-LAT detection
- GRB 160910A: Fermi GBM observation
- Konus-Wind observation of GRB 160905A
- GRB 160824A: 15 GHz upper limits from AMI
- GRB 160821B: 15 GHz upper limits from AMI
- GRB 160905A: Swift/UVOT Detection
- GRB 160905A: Swift-BAT refined analysis
- Swift Trigger 711158 is not an astrophysical event
- GRB 160905A: Swift-XRT refined Analysis
- GRB 160821A: 15 GHz upper limits from AMI