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"- GRB220611A: Gemini Optical Afterglow Confirmation
- GRB 220618A: Enhanced Swift-XRT position
- GRB 220617A: Swift-XRT observations
- GRB 220618A: Swift detection of a burst
- Swift GRB220618.38: Global MASTER-Net observations report
- GRB 220617A: Fermi-LAT detection
- GRB 220617B: Swift ToO observations
- Fermi GRB 220617A: Global MASTER-Net observations report
- GRB 220617A: Fermi GBM Final Real-time Localization
- GRB 220611A: Gemini Ks counterpart detection
- Fermi trigger No 677174940: Global MASTER-Net observations report
- Konus-Wind detection of GRB 220613A
- IPN triangulation of GRB 220613A
- Konus-Wind detection of an intermediate flare from SGR 1935+2154 on June 16
- GRB 220611A: Gemini South Infrared Detection
- IPN triangulation of GRB 220606C
- GRB 220611A: Swift/UVOT Upper Limits
- Fermi trigger No 676909037: Global MASTER-Net observations report
- GRB 220612A: CALET Gamma-Ray Burst Monitor detection
- GRB 220612A: Swift/BAT-GUANO detection
- GRB 220611A: Swift-BAT refined analysis
- GRB 220608B: Detection by VZLUSAT-2
- Swift GRB 220611A: Global MASTER-Net observations report
- GRB 220611A: Swift-XRT refined Analysis
- GRB 220610B: AstroSat CZTI detection
- GRB 220611A: Enhanced Swift-XRT position
- GRB 220611A: Swift detection of a burst
- IPN triangulation of GRB 220609B
- Fermi GRB 220610A: Global MASTER-Net observations report
- GRB 220610A: Fermi GBM Final Real-time Localization
- Fermi trigger No 676537486: Global MASTER-Net observations report
- GRB 220609B: AstroSat CZTI detection
- GRB 220609B: CALET Gamma-Ray Burst Monitor detection
- Fermi trigger No 676366592: Global MASTER-Net observations report
- GRB 220608A: AstroSat CZTI detection
- GRB 220609A: Fermi GBM Final Real-time Localization
- GRB 220606A: Fermi GBM observation
- GRB 220606C: CALET Gamma-Ray Burst Monitor detection
- Fermi GRB 220608A: Global MASTER-Net observations report
- GRB 220608A: Fermi GBM Final Real-time Localization
- GRB 220606B: Gemini South Optical Observations
- MAXI GRB220607.31: Global MASTER-Net observations report
- MAXI GRB220607.41: Global MASTER-Net observations report
- GRB 220606B: Fermi GBM Observation
- GRB 220606B: Swift follow-up observations
- Konus-Wind detection of GRB 220601A
- GRB 220606A: Swift/BAT-GUANO detection
- GRB 220606B: GUANO coordinate correction to GCN 32167
- GRB 220527A: A BdHN I with a clear UPE phase
- GRB 220606B: Swift ToO observations
- GRB 220606B: Swift/BAT-GUANO candidate arcminute localization of a short burst
- Fermi GRB 220606B: Global MASTER-Net observations report
- GRB 220606B: Fermi GBM Final Real-time Localization
- GRB 220606A: Fermi GBM Final Real-time Localization
- IPN triangulation of GRB 220601A (long)
- Fermi trigger No 675992935: Global MASTER-Net observations report
- GRB 220603A: Swift/BAT-GUANO detection outside the coded FOV
- Fermi-GBM will trial new SAA regions from Tuesday June 7th
- GRB 220527A: MITSuME Akeno continued optical observation
- GRB 220527A: Lick 3m Optical Observations
- Konus-Wind detection of GRB 220528A
- IPN triangulation of GRB 220528A (short)
- GRB 220528A: Fermi GBM Observation
- Trigger 1108538: Swift detection of a burst from SGR J1935+2154
- Fermi GRB 220530A: Global MASTER-Net observations report
- Konus-Wind observation of GRB 220527A
- Swift trigger 1108515 is not an astrophysical event
- GRB 220530A: Fermi GBM Final Real-time Localization
- Correction to GCN 32148: Should be GRB 220528A
- GRB 220528B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220528A: Fermi GBM Final Localization
- GRB 220527A: AST3-3 Yaoan Optical Observation
- GRB 220527A: REM optical/NIR observations
- GRB 220527A: VLT/X-shooter spectroscopic redshift
- GRB 220527A: MeerLICHT afterglow observations
- Fermi trigger No 675411172: Global MASTER-Net observations report
- GRB 220527A: NOT optical photometry and spectroscopic redshift
- GRB 220527A: AstroSat CZTI detection
- GRB 220527A: CALET Gamma-Ray Burst Monitor detection
- GRB 220527A: MITSuME Akeno optical observation
- LAT GRB220527.39: Global MASTER-Net observations report
- GRB 220527A: Swift/UVOT detection
- GRB 220527A: Swift-XRT afterglow detection
- Swift trigger 1108208 is not an interesting astrophysical event.
- GRB 220527A: Fermi GBM Observation
- GRB 220527A: Swift ToO observations
- GRB 220527A: Fermi-LAT detection
- GRB 220527A: Fermi GBM Final Localization
- GRB 220527A: AGILE detection
- GRB 220521B: CALET Gamma-Ray Burst Monitor detection
- GRB 220525A: Fermi GBM Detection
- Konus-Wind detection of a burst from SGR 1935+2154 on 2022 May 25
- GRB 220525A: CALET Gamma-Ray Burst Monitor detection
- GRB 220523B: CALET Gamma-Ray Burst Monitor detection
- Konus-Wind detection of GRB 220524B
- Konus-Wind detection of GRB 220525A
- Konus-Wind detection of GRB 220524A
- Swift GRB220526.48: Global MASTER-Net observations report
- Fermi GRB 220525A: Global MASTER-Net observations report
- IPN triangulation of GRB 220525A