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').
18178 results found.
- GRB 250101A: GMG spectroscopic redshift at z ~ 2.481
- GRB 250101A: Swift/UVOT Detection
- GRB 250101A: 1.6m Mephisto multi-band optical followup
- GRB 250101A: Swift-XRT refined Analysis
- GRB 250101A: Montarrenti Observatory optical observations and rebrightening
- GRB 250101A: LCOGT optical afterglow detection
- GRB 250101A: OASDG optical observations
- GRB 250101A: BOOTES-4/MET optical afterglow detection
- GRB 250101A: SAO RAS optical observations
- GRB 250101A: Enhanced Swift-XRT position
- GRB 250101A: Xinglong-2.16m spectroscopic redshift
- GRB 250101A: SVOM/C-GFT early optical observations
- GRB 250101A: MASTER earlier OT observations with SOSS emission features
- GRB 250101A: Nanshan/HMT optical observations
- GRB 250101A : GIT optical detection
- GRB 250101A: Swift detection of a burst with an optical counterpart
- Swift GRB250101.56: Global MASTER-Net observations report
- EP241217a: VLA Radio Detection
- GRB 241229A: EP-FXT X-ray afterglow confirmation
- GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
- GRB 241229B: SVOM/GRM observation
- EP241217A: J band upper limit by SYSU 80cm telescope
- GRB 241228B: SAO RAS optical observations
- GRB 241229B: SVOM/VT optical candidate
- GRB 241229A: Swift-XRT observations
- Konus-Wind detection of GRB 241228A
- GRB 241229A: EP-FXT afterglow candidates
- GRB 240606B: 7DT Optical upper limits
- GRB 241229B: Swift-BAT refined analysis
- GRB241229B: UVOT upper limits
- GRB 241228B: D50 optical detection
- GRB 241228B: Fermi GBM Observation
- GRB 241228B: Swift-XRT afterglow detection
- GRB 241229B: Fermi GBM Observation
- GRB 241229A: Swift ToO observations
- GRB 241229B: Swift-XRT refined Analysis
- Swift GRB 241229B: Global MASTER-Net observations report
- GRB 241228A: NOT optical upper limits
- GRB 241228A: Swift-BAT refined analysis
- GRB 241228B: Swift/BAT-GUANO localization skymap of a burst
- GRB 241229B: Swift detection of a burst
- GRB 241228A: Fermi GBM Observation
- Swift GRB 241228A: Global MASTER-Net observations report
- GRB 241226A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241228A: GROWTH-India telescope optical upper limit
- GRB 241228B: Swift ToO observations
- GRB 241228A: Swift-XRT refined Analysis
- GRB 241228A: Swift/UVOT Upper Limits
- GRB 241228A: Enhanced Swift-XRT position
- GRB 241228A: Swift detection of a burst
- GRB 241223A: Swift-XRT observations
- GRB241113A: 7DT Optical upper limits
- GRB 241223A: GOTO optical observations summary
- GRB 241223A: Swift ToO observations
- GRB 241218A: Mondy AZT-33IK optical upper limit
- GRB 241218A: Swift/UVOT Upper Limits
- EP241217a: optical upper limit with the Liverpool Telescope
- GRB 241209B: EP-FXT afterglow detection
- GRB 241218A: NOT optical upper limits
- GRB 241218A: Swift-BAT refined analysis
- EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
- GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
- GRB 241218A: REM optical upper limit
- GRB 241217A/EP241217b: REM optical/NIR upper limits
- EP241217a: REM optical/NIR upper limits
- GRB 241218a: Liverpool Telescope optical follow-up
- GRB 241217a: Liverpool Telescope optical follow-up
- GRB 241218A: Swift-XRT refined Analysis
- GRB 241209A: ATCA radio follow-up observations
- GRB 241218A: LCOGT Optical Upper Limit
- GRB 241218A: Enhanced Swift-XRT position
- GRB 241218A: Swift detection of a burst
- GRB 241217A : SVOM/VT optical afterglow detection
- GRB 241217A: Swift-XRT afterglow detection
- EP241217a: Swift-XRT Detection
- GRB 241214A: GRBAlpha detection
- GRB 241213A (EP241213a): GRBAlpha detection
- GRB 241209D: GRBAlpha detection
- GRB 241213A: Swift-BAT refined analysis
- GRB 241214A: Swift/BAT-GUANO localization skymap of a burst
- Konus-Wind detection of GRB 241213A (EP 241213a)
- GRB 241212A: Swift-XRT observations
- GRB 241213B: Swift-XRT observations
- GRB 241209D: CALET Gamma-Ray Burst Monitor detection
- GRB 241213A: SVOM/VT optical candidate
- GRB 241213B: Tiled Swift observations
- GRB 241213A: Swift/UVOT Upper Limits
- GRB 241213A: Swift-XRT refined Analysis
- GRB 241212A: Swift ToO observations
- GRB 241213A: LCOGT Optical Upper Limits
- EP241213a: EP detection of An X-ray Transient
- GRB 241213A: REM optical/NIR upper limits
- GRB 241213A: Enhanced Swift-XRT position
- Swift GRB 241213A: Global MASTER-Net observations report
- GRB 241213A: Swift detection of a burst
- GRB 241209A: Chandra X-ray Detection
- Konus-Wind detection of GRB 241209B
- GRB 241209B: GRBAlpha detection
- GRB 241129A: Fermi GBM Observation
- GRB 241209B: Swift/BAT-GUANO localization skymap of a burst