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').
774 results found.
- GRB 230204B: CALET Gamma-Ray Burst Monitor detection
- GRB 230204B: ATCA radio detection
- GRB 230204B: MASTER early OT detection
- GRB 230204B: Swift/UVOT Upper Limits
- GRB 230204B: Fermi GBM detection
- GRB 230204B: Swift-XRT afterglow detection
- GRB 230204B: 3.6m DOT optical observation
- GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
- GRB 230204B: Swift ToO observations
- GRB 230204B: Detection by GRBAlpha
- GRB 230204B: AGILE detection
- GRB 230204B: GIT discovery of the likely optical afterglow
- GRB 230204B: AstroSat CZTI detection
- GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 230204B: MAXI/GSC detection
- GRB 230111A: Fermi GBM Observation
- GRB 230111A: MAXI/GSC detection
- GRB 221028B: MAXI/GSC detection
- Konus-Wind detection of GRB 221017A
- GRB 221017A: CALET Gamma-Ray Burst Monitor detection
- GRB 221017A: Swift-XRT observations
- GRB 221017A: Swift ToO observations
- IPN triangulation of GRB 221017A (long)
- MAXI GRB221017.24: Global MASTER-Net observations report
- GRB 221017A: MAXI/GSC detection
- MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
- MAXI GRB 221006A: Redshifts of the possible host galaxies
- GRB 221006A: Swift-XRT afterglow detection
- Afterglow limits of GRB 221006A from OHP
- GRB 221009A: NICER follow-up observations
- GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
- GRB 221006A: Swift ToO observations
- GRB 221006A: CALET Gamma-Ray Burst Monitor detection
- GRB 221009: Swift/UVOT Detection
- GRB 221009A BOOTES-2/TELMA and OSN optical detections
- GRB 221008A: Swift-XRT observations
- GRB 221008A: Tiled Swift observations
- GRB 221008A: MAXI/GSC detection
- GRB 221006A: Swift-XRT observations
- GRB 221006A: Tiled Swift observations
- GRB 221006A: MAXI/GSC detection
- Fermi trigger No 684716840: Global MASTER-Net observations report
- GRB 220813A: Swift/UVOT Detection
- GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
- MAXI GRB220706.73: Global MASTER-Net observations report
- Trigger 1113743: Swift detection of MAXI J0655-013
- Swift Detection of MAXI J0655-013
- MAXI GRB220607.31: Global MASTER-Net observations report
- MAXI GRB220607.41: Global MASTER-Net observations report
- Konus-Wind detection of GRB 220506A
- Konus-Wind detection of GRB 220514B
- GRB 220514B: Swift-XRT observations
- GRB 220514B: Tiled Swift observations
- GRB 220514B: MAXI/GSC detection
- MAXI GRB220514.98: Global MASTER-Net observations report
- GRB 220506A: MITSuME Akeno optical upper limits
- GRB 220506A: GIT optical upper limit.
- GRB 220506A: BOOTES-5/JGT optical upper limit
- GRB 220506A: Swift-XRT afterglow detection
- GRB 220506A: Tiled Swift observations
- GRB 220506A/MAXI J1558-266: MAXI/GSC detection
- MAXI GRB220506.27: Global MASTER-Net observations report
- Fermi GRB 220411A: Global MASTER-Net observations report
- GRB 220310A: MITSuME Akeno optical observation
- IPN triangulation of GRB 220310A
- GRB 220310A: [KAO-Egypt] SDSS r, i observation
- Konus-Wind detection of GRB 220310A
- GRB 220310A: GIT confirmation of optical afterglow.
- GRB 220310A: MASTER optical counterpart detection
- GRB 220310A: Swift ToO observations
- GRB 220310A: CALET Gamma-Ray Burst Monitor detection
- GRB 220310A: MAXI/GSC detection
- MAXI GRB220310.02: Global MASTER-Net observations report
- GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
- GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
- GRB 211227A: CALET Gamma-Ray Burst Monitor detection
- GRB 211227A: MAXI/GSC detection
- GRB 211225A: MITSuME Akeno optical upper limits
- GRB 211226A: AGILE/MCAL detection of a burst
- MAXI GRB211225.14: Global MASTER-Net observations report
- GRB 211225A/MAXI J0827-071: MAXI/GSC detection
- GRB 211218A: MITSuME Akeno optical upper limits
- GRB 211218A, MAXI J0909-041: MAXI/GSC detection
- MAXI GRB211218.04: Global MASTER-Net observations report
- GRB 211115A: CALET Gamma-Ray Burst Monitor detection
- GRB 211115A: MAXI/GSC detection
- MAXI GRB210709.93: Global MASTER-Net observations report
- Fermi trigger No 645857659: Global MASTER-Net observations report
- Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
- GRB 210607A/MAXI J1733-222: MAXI/GSC detection
- MAXI GRB210607.82: Global MASTER-Net observations report
- Konus-Wind detection of GRB 210602A
- MAXI GRB210602.50: Global MASTER-Net observations report
- GRB 210602A: CALET Gamma-Ray Burst Monitor detection
- GRB 210602A: MAXI/GSC detection
- GRB 210528B: DDOTI Upper Limits on the Afterglow
- MAXI GRB210528.95: Global MASTER-Net observations report
- GRB 210528B: MAXI/GSC detection
- MAXI GRB210521.54: Global MASTER-Net observations report
- GRB 210521A: MAXI/GSC detection