GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"- IceCube-220421A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220418B: Swift-XRT observations
- IceCube Alert 220421.22: Global MASTER-Net observations report
- GRB 220418B Fermi GBM observation
- Fermi trigger No 672093919: Global MASTER-Net observations report
- “GRB 220420A” is not a GRB
- GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220403C: Further Swift-XRT observations
- GRB 220418B: Swift ToO observations
- GRB 220417A: Fermi GBM detection
- GRB 220418B: Swift/BAT-GUANO refined location of a short burst
- IPN triangulation of GRB 220411A
- GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
- GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220412B: Swift/UVOT Upper Limits
- Fermi GRB 220418A: Global MASTER-Net observations report
- GRB 220418B: Fermi GBM Final Real-time Localization
- GRB 220418A: Fermi GBM Final Real-time Localization
- Fermi GRB 220417A: Global MASTER-Net observations report
- GRB 220417A: Fermi GBM Final Real-time Localization
- Fermi trigger No 671729344: Global MASTER-Net observations report
- GRB 220412B: Swift-BAT refined analysis
- Konus-Wind detection of GRB 220412B
- GRB 220412B: Fermi GBM observation
- Konus-Wind detection of GRB 220403C
- GRB 220408B: Fermi GBM observation
- Konus-Wind detection of GRB 220408B
- GRB 220412B: TNG optical observations
- GRB 220412A: GRANDMA observations
- GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve
- GRB 220412A: BOOTES-network optical upper limits
- GRB 220412B: BOOTES-1 optical upper limit
- GRB 220412A: Swift-BAT refined analysis
- GRB 220412A: RATIR Observations of the Fading Afterglow
- GRB 220412B: Swift-XRT observations
- GRB 220408B: Fermi-LAT detection
- IPN triangulation of short/soft GRB 220406A
- Swift GRB 220412B: Global MASTER-Net observations report
- GRB 220408A: HCT optical upper limit
- GRB 220412B: GIT optical upper limit
- GRB 220412A: MITSuME Akeno optical upper limits
- Correction to GCN 31888: GRB 220412A: Swift-XRT refined Analysis
- GRB 220412B: MITSuME Akeno optical upper limits
- GRB 220412A: Swift-XRT refined Analysis
- GRB 220412A: Enhanced Swift-XRT position
- GRB 220412B: Swift detection of a short burst
- GRB 220412A: Swift/UVOT Upper Limits
- GRB 220408A: GRANDMA observations
- GRB 220403B: GRANDMA observations
- GRB 220412A: RATIR Afterglow Candidate
- GRB 220412A: Swift detection of a burst
- Swift GRB220412.28: Global MASTER-Net observations report
- GRB 220411A: AstroSat CZTI detection
- IPN triangulation of GRB 220408B
- IPN triangulation of GRB 220403C
- GRB 220403B: Swift/UVOT Detection
- GRB 220408A: Lowell Discovery Telescope Optical Observations
- GRB 220408A: Swift-BAT refined analysis
- Fermi GRB 220411A: Global MASTER-Net observations report
- GRB 220411A: BALROG localization (Fermi Trigger 671354405/ GRB 220411306)
- GRB 220411A: Fermi GBM Final Real-time Localization
- GRB 220408A: RATIR Optical and NIR Observations
- GRB 220403B: 1.3m DFOT Optical upper limit
- GRB 220408A: 1.3m DFOT Optical upper limit
- GRB 220408A: LOAO, DOAO, and, SAO optical upper limit
- GRB 220403C: Swift-XRT observations
- GRB 220408A: redshift lower limit estimating
- GRB 220408A: NOT optical observations and archival detection
- GRB 220408B: AstroSat CZTI detection
- GRB 220408A: LCO Optical Afterglow Detection
- GRB 220408A: Swift-XRT refined Analysis
- GRB 220403C: Swift ToO observations
- GRB 220408A: BOOTES-5/JGT optical afterglow detection
- Fermi GRB 220408B: Global MASTER-Net observations report
- GRB 220408A: GIT optical upper limit
- GRB 220408A: Fermi GBM observation
- GRB 220408A: Swift/UVOT Detection
- GRB 220408B: Fermi GBM Final Localization
- GRB 220408A: Xinglong-2.16m optical upper limit
- GRB 220408A: Enhanced Swift-XRT position
- Chandra upper limit at the location of GRB 220408A
- GRB 220408A: KAIT Optical Observations
- Fermi GRB 220408A: Global MASTER-Net observations report
- GRB 220408A: Swift detection of a burst with an optical counterpart, possibly associated with M51
- GRB 220408A: Fermi GBM Final Real-time Localization
- ZTF22aaajecp/AT2022cmc: continued optical observations (Mondy, SAO RAS, CrAO)
- Fermi-LAT Gamma-ray Observations of IceCube-220405B
- GRB 220403B: Mondy optical upper limit
- IceCube-220405A: No Candidate Counterparts from the Zwicky Transient Facility
- IceCube-220405B: No Candidate Counterparts from the Zwicky Transient Facility
- GRB 220403B: 1.5m OSN optical observation
- IceCube Alert 220405.93: Global MASTER-Net observations report
- IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220404A: Swift-BAT refined analysis
- GRB 220403B: Kitab optical observations
- Fermi-LAT Gamma-ray Observations of IceCube-220405A
- GRB 220405A: Fermi GBM Final Localization
- GRB 220403B: Swift-BAT refined analysis
- IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube Alert 220405.21: Global MASTER-Net observations report