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').
17087 results found.
- GRB 240101B: Swift-BAT refined analysis
- GRB 240102A: Enhanced Swift-XRT position
- GRB 240101B: Swift-XRT refined Analysis
- GRB 240102A: Swift-XRT refined Analysis
- GRB 240102A: LCOGT Optical Upper Limits
- GRB240102A: BOOTES-6/DPRT optical upper limit
- GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- GRB 240102A: Swift detection of a burst
- GRB 240101A: Terskol Zeiss-2000 optical observations
- GRB 240101B: Swift/UVOT Upper Limits
- GRB 240101A: Swift/UVOT Upper Limits
- GRB 240101A: Swift-XRT refined Analysis
- GRB 240101B: Enhanced Swift-XRT position
- GRB 240101B: KAIT Optical Upper Limit
- GRB 240101A: KAIT Optical Upper Limit
- GRB 240101A: Enhanced Swift-XRT position
- Swift GRB240101.85: Global MASTER-Net observations report
- GRB 240101B: Swift detection of a burst
- GRB 240101A: Swift detection of a burst
- GRB231230A: Fermi GBM Observation
- GRB 231230A: Swift-XRT refined Analysis
- GRB 231230A: GOTO optical upper limits
- GRB 231230A: Enhanced Swift-XRT position
- GRB 231230A: Swift/UVOT Upper Limits
- GRB 231230A: Prompt enhanced Swift-XRT position
- GRB 231230A: Swift detection of a burst
- Swift GRB231230.06: Global MASTER-Net observations report
- GRB 231210B: BOOTES-7 optical upper limit
- Swift Triggers 1205103, 1205104, 1205107 and 1205110 are not astrophysical events
- LIGO/Virgo/KAGRA S231224e: Upper limits from Swift/BAT-GUANO
- GRB 231222B: Swift-XRT afterglow detection
- GRB 231222B: Fermi-LAT detection
- 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: 10.4 m GTC optical upper limit
- 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: 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: NOT optical observations
- GRB 231214A: Swift/UVOT Upper Limits
- GRB 231205B: VZLUSAT-2 detection
- GRB 231215A: Fermi GBM observation
- GRB 231215A: CALET Gamma-Ray Burst Monitor 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