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"26038 results found.
- GRB 221206B: Detection by GRBAlpha
- GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
- GRB 221206B: Swift ToO observations
- Swift/BAT trigger #1143281 is not a GRB
- Swift GRB221204.45 AKO Upper Limit
- Swift GRB221204.45: Global MASTER-Net observations report
- GRB 221202A: Swift/UVOT Detection
- GRB 221202A: Swift-BAT refined analysis
- GRB 221202A: VLT/FORS2 Afterglow Discovery
- GRB 221201A: Swift-BAT refined analysis
- GRB 221201A: Fermi GBM observation
- GRB 221202A: Swift-XRT refined Analysis
- GRB 221202A: LCOGT Optical Upper Limits
- GRB 221202A: Enhanced Swift-XRT position
- GRB 221202A: MeerLICHT upper limits
- GRB 221202A: Swift detection of a burst
- Swift GRB221202.84: Global MASTER-Net observations report
- GCN: GRB 221201A: Swift/UVOT Upper Limits
- GRB 221201A: Swift-XRT refined Analysis
- GRB 221201A: Enhanced Swift-XRT position
- Swift GRB 221201A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 221124A
- GRB 221201A: Swift detection of a burst
- GRB 221126A: Fermi GBM observation
- GRB 221126A: AGILE detection
- GRB 221126A: AstroSat CZTI detection
- GRB 221126A: Swift/BAT-GUANO detection outside the coded FOV
- IPN triangulation of GRB 221124A (long)
- GRB 221124A: Swift/BAT-GUANO detection
- GRB 221120A: Detection by VZLUSAT-2
- GRB 221120A: TURBO Optical Upper Limit
- GRB 221120A: VIRT Optical Upper Limit
- GRB 221009A：DAMPE observed a 34.7 GeV photon at 1.36 hour after the GBM trigger
- IPN triangulation of GRB 221121A (long)
- GRB 221120A: Swift-BAT refined analysis
- GRB 221120A: AKO Telescope Upper Limits
- GRB221120A: WIRC near-IR imaging of the afterglow candidate
- GRB 221120A: Liverpool Telescope Upper Limits
- GRB 221120A: Archival PS1 Imaging of Faint Source near XRT position
- GRB 221120A: Fermi GBM observation
- GRB 221120A: Swift-XRT refined Analysis
- GRB 221120A: Enhanced Swift-XRT position
- GRB221120A: Montarrenti Observatory Upper Limit
- GRB 221120A is a short burst
- GRB 221120A: Swift/UVOT Upper Limits
- GRB 221120A: LDT Optical Afterglow Candidate
- GRB 221120A: GIT upper limits on optical afterglow
- GRB 221120A: Swift detection of a likely short burst
- GRB 221119A: Fermi-LAT detection
- GRB 221009A: Japanese VLBI Network observation
- GRB 221115B: CALET Gamma-Ray Burst Monitor detection
- Correction to GCN 32646 (GRB 221009A (Swift J1913.1+1946): MeerLICHT observations)
- GRB 221115B : MeerLICHT upper limits
- GRB 221115A: Fermi GBM detection
- GRB 221115B: Swift/BAT-GUANO arcminute localization
- GRB 221115A: Swift/BAT-GUANO detection
- GRB 221110A: GRANDMA observations
- GRB 221009A: GRANDMA/Kilonova-Catcher observations
- GRB 221110A: Swift/UVOT Detection and Corrected UVOT Position
- GRB 221110A: Swift-BAT refined analysis
- GRB 221110A: Swift-XRT refined Analysis
- GRB 221110A: Enhanced Swift-XRT position
- GRB 221110A: VLT/X-shooter redshift
- GRB 221110A: COATLI Afterglow detection
- GRB 221110A: LCOGT Optical Afterglow Detection
- GRB 221110A: Swift detection of a burst with an optical counterpart
- Swift GRB221110.10: Global MASTER-Net OT detection
- Swift GRB221110.10: Global MASTER-Net observations report
- GRB 221009A: Hubble Space Telescope observations
- GRB 221107A: Fermi GBM Observation
- GRB 221107A: Detection by GRBAlpha
- GRB 221107A: Swift/BAT-GUANO detection outside the coded FOV
- Correction to GCN 32852 (GRB 221009A: SARA-RM 1m Optical Afterglow Detection)
- GRB 221029A: CALET Gamma-Ray Burst Monitor detection
- High-precision position of the compact radio counterpart to GRB221009A
- GRB 221028A: GRANDMA observations
- GRB 221027B: GRANDMA observations
- GRB 221028A: Detection by VZLUSAT-2
- GRB 221028A: Swift-XRT refined Analysis
- GRB 221028A: 1.3m DFOT Optical upper limit
- GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
- GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
- GRB 221028A: AKO Optical Upper Limit
- GRB 221028A, Swift-BAT refined analysis
- GRB 221027B: Swift-BAT refined analysis
- GRB 221029A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 221028A: CrAO/ZTSh optical upper limit
- GRB 221028A: COATLI Upper Limits
- Trigger 1132968: Swift trigger is the Crab
- GRB 221028A: HCT optical upper limit
- GRB 221028A: AGILE detection
- GRB 221028A: MITSuME Okayama optical upper limits
- GRB 221028A: LCOGT Optical Upper Limits
- GRB 221027B: COATLI Upper Limits
- Swift GRB 221028A: Global MASTER-Net observations report
- GRB 221028A: BOOTES-4/MET optical upper limit
- GRB 221028A: GIT optical upper limit
- GRB 221027B: Swift/UVOT Upper Limits
- GRB 221028A: Swift detection of a burst
- GRB 221027B: FRAM-ORM and Ondrejov SBT optical limits