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"- 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
- IPN triangulation of GRB 220524B
- Fermi-LAT Gamma-ray Observations of IceCube-220524A
- IPN triangulation of GRB 220524A
- IceCube-220524A: Upper limits from a search for additional neutrino events in IceCube
- GRB 220525A: BALROG localization (Fermi Trigger 675130259 / GRB 220525008)
- GRB 220525A: Fermi GBM Final Real-time Localization
- GRB 220521A: ATCA detection
- GRB 220521A: ALMA detection
- Konus-Wind detection of GRB 220522B
- IPN triangulation of GRB 220522B
- GRB 220521A: BOOTES-2/TELMA and CAHA 2.2m telescope optical upper limit
- Konus-Wind detection of GRB 220521B
- GRB 220521A: classification and detection by SPI-ACS/INTEGRAL
- IPN triangulation of GRB 220521B
- GRB 220521A: ISON-Castelgrande observatory optical observations
- IceCube-220524A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 220521A: MITSuME Akeno optical upper limits
- Fermi GRB 220523B: Global MASTER-Net observations report
- GRB 220521A: Gemini Observations
- GRB 220523B: Fermi GBM detection
- GRB 220521A: MMT Afterglow Imaging
- GRB 220521A: REM optical/NIR upper limits
- GRB 220514A: Swift/BAT-GUANO detection outside the coded FOV
- VLA observations of GW170817 at ~4.8 years after the merger
- Fermi GRB 220523A: Global MASTER-Net observations report
- GRB 220523A: Fermi GBM Final Real-time Localization
- GRB 220521A: LCO Optical Detection
- GRB 220521A: Swift-BAT refined analysis
- GRB 220521A: Fermi GBM detection
- GRB 220521A: Sintesz-Newton/CrAO optical upper limit
- GRB 220521A: RATIR Optical and NIR Observations
- GRB 220521A: Swift-XRT refined Analysis
- GRB 220521A: Swift/UVOT Upper Limits
- Fermi GRB 220522A: Global MASTER-Net observations report
- Fermi trigger No 674868783: Global MASTER-Net observations report
- GRB 220521A: SAO RAS optical observations
- GRB 220521A: Enhanced Swift-XRT position
- GRB 220522A: Fermi GBM Final Real-time Localization
- GRB 220521A: NOT spectroscopic redshift