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"25891 results found.
- GRB 231222A: Tiled Swift observations
- GRID detection of GRB 231215A
- GRB 231220A: Swift-XRT follow-up observations
- GRB 231220A: Swift ToO observations
- GRB 231220A: Swift/BAT-GUANO arcminute localization of a long burst
- GRB 231210B: new optical transient detected with the Greenhill Observatory University of Tasmania within the BAT-Swift enhanced position
- GRID detection of GRB 231205B
- GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
- GRB 231214B: Fermi GBM observation
- GRB 231216A: optical upper limits from the INAF Asiago Observatory
- GRB 231216A: 10.4 m GTC optical upper limit
- GRB 231215A: AMI-LA radio detection
- GRB 231216A: Nanshan/HMT optical upper limit
- GRB 231216A: LCOGT Optical Upper Limits
- GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231216A: Swift-XRT refined analysis correction
- GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231216A: Swift-XRT refined Analysis
- GRB 231216A: AST3-3 YaoAn Optical Upper Limit
- GRB 231216A: REM NIR upper limits
- GRB 231216A: Swift/UVOT Upper Limits
- GRB 231216A: Swift-BAT refined analysis
- GRB 231215A: Swift-BAT refined analysis
- GRB 231214A: Swift-BAT refined analysis
- GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
- GRB 231216A: GIT optical upper limit
- GRB 231216A: NOT optical upper limits
- GRB 231216A: BOOTES-2/TELMA optical upper limit
- GRB 231215A: GRBAlpha detection
- Swift GRB231216.77: Global MASTER-Net observations report
- GRB 231216A: Swift detection of a burst
- Konus-Wind detection of GRB 231215A
- GRB 231215A: optical afterglow detection from the INAF Asiago Observatory
- GRB 231215A: NOT optical observations
- GRB 231214A: Swift/UVOT Upper Limits
- GRB 231215A: Redshift from OSIRIS+ / GTC
- GRB 231205B: VZLUSAT-2 detection
- GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
- GRB 231215A: Fermi GBM observation
- GRB 231215A: CALET Gamma-Ray Burst Monitor detection
- GRB 231215A : OHP/T193 optical afterglow detection
- GRB 231215A: Swift/UVOT Detection
- GRB 231215A: Swift-XRT refined Analysis
- GRB 231215A: BOOTES-4/MET optical detection
- GRB 231215A: AKO Optical Upper Limit
- GRB 231215A: AGILE detection
- GRB 231214A: Fermi GBM observation
- Konus-Wind detection of GRB 231210B
- GRB 231215A: Enhanced Swift-XRT position
- GRB 231214A: REM optical/NIR upper limits
- GRB 231215A: GROWTH-India optical follow-up
- GRB 231215A : Nanshan/HMT optical observations
- GRB 231215A: AstroSat CZTI detection
- GRB 231215A : MITSuME Akeno optical afterglow candidate detection
- GRB 231214A: Swift-XRT refined Analysis
- GRB 231215A: Mondy optical bright afterglow detection
- GRB 231214A: AstroSat CZTI detection
- GRB 231215C: MASTER OT detection
- Swift GRB231215.41: Global MASTER-Net observations report
- GRB 231215A: Swift-XRT observations
- GRB 231215A: Swift detection of a burst
- GRB 231214A: Fermi-LAT detection
- GRB 231214A: Enhanced Swift-XRT position
- GRB 231214B: Swift/BAT-GUANO detection of a burst
- GRB231214A: BOOTES-6/DPRT optical upper limit
- Swift GRB231214.85: Global MASTER-Net observations report
- GRB 231214A: Swift detection of a burst
- GRB 231210B: REM optical/NIR upper limits
- LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
- GRB 231210B: MeerLICHT afterglow observations
- GRB 231210B: Swift-BAT refined analysis
- GRB 231210B: Swift-XRT refined Analysis
- GRB 231210B: Enhanced Swift-XRT position
- GRB 231210B: VLT/X-shooter redshift
- GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
- GRB 231210B: Swift detection of a burst with optical counterpart
- Swift GRB231210.90: Global MASTER-Net OT detection
- Swift GRB231210.90: Global MASTER-Net observations report
- IPN triangulation of GRB 231129C
- GRB231205B: Swift/UVOT Upper Limits
- GRB 231205B: Swift-BAT refined analysis
- GRB 231205B: 1.3m DFOT Optical upper limit
- GRB 231205B: optical upper limit in TSHAOand AbAO
- GRB 231205B: AGILE detection
- GRB 231205B: Ondrejov D50 optical upper limit
- GRB 231205B: Swift-XRT refined Analysis
- GRB 231205B: REM optical/NIR upper limits
- GRB 231129C: ASIM MXGS observation and localization
- GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
- GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
- GRB 231205B : MITSuME Akeno optical upper limits
- GRB 231205B: Zadko observatory - Gingin optical observations
- GRB 231205B: Gaoyazi/GOT optical upper limit
- GRB 231205B: Nanshan/HMT optical upper limit
- GRB 231205B: GECAM-B detection of a long burst
- GRB 231205B: LCOGT Optical Upper Limits
- GRB 231205A: DDOTI Upper Limits on the Afterglow
- GRB 231205B: Enhanced Swift-XRT position
- Swift GRB231205.70: Global MASTER-Net observations report