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"35259 results found.
- GRB 221009A: Redshift from X-shooter/VLT
- GRB 221009A: Nanshan/NEXT photometry and Xinglong-2.16m spectroscopy
- GRB 221009A (Swift J1913.1+1946): MeerLICHT observations
- GRB 221009A (Swift J1913.1+1946): Mondy optical observations
- GRB 221009A BOOTES-2/TELMA and OSN optical detections
- GRB 221009A: Fermi GBM observation
- IPN triangulation of extremely bright GRB 221009A
- Swift J1913.1+1946: Optical photometry
- Swift J1913.1+1946: Liverpool Telescope imaging and spectroscopy
- GRB 221009A or Swift J1913.1+1946: Fermi-LAT detection
- GRB 221009A: Fermi GBM detection of an extraordinarily bright GRB
- GRB 221009A: Swift detected transient may be GRB
- GRB 221008A: Swift-XRT observations
- GRB 221008A: Tiled Swift observations
- GRB 221008A: MAXI/GSC detection
- GRB 220915A: Detection by GRBAlpha
- GRB 221006A: Swift-XRT observations
- GRB 221006A: Tiled Swift observations
- GRB 221006A: MAXI/GSC detection
- GRB 220930A: MITSuME Akeno optical upper limits
- GRB 220912A: Detection by VZLUSAT-2
- GRB220927A: Detection by GRBAlpha
- Fermi GBM trigger 686565116/221004355 is not a GRB
- Fermi GBM trigger 686435254/221002852 is not a GRB
- Fermi GBM trigger 686350260/221001869 is not a GRB
- GRB 220921A: ATCA detection of radio counterpart
- GRB 220930A: AbAO Optical Upper Limit
- Konus-Wind detection of GRB 220930A
- GRB 220930A: AstroSat CZTI detection
- GRB 220930A: Swift-BAT refined analysis
- GRB 220930A: Swift-XRT refined Analysis
- GRB 220930A: LCOGT Optical Upper Limits
- GRB 220930A: Swift/UVOT Upper Limits
- GRB 220930A: Enhanced Swift-XRT position
- Swift GRB 220930A: Global MASTER-Net observations report
- GRB 220930A: BOOTES-5/JGT early optical upper limit
- GRB 220930A: Prompt enhanced Swift-XRT position
- GRB 220930A: COATLI Upper Limits
- GRB 220930A: Swift detection of a burst
- Konus-Wind detection of GRB 220927A
- Fermi GRB 220927A: Global MASTER-Net observations report
- IPN triangulation of GRB 220927A (long)
- GRB 220921A: LCOGT Optical Observations
- GRB 220611A: Host galaxy redshift from VLT/X-shooter
- GRB 220927A: Fermi GBM Final Localization
- GRB 220924A: Fermi GBM detection
- Ultra-long GRB 220525B: Konus-Wind and Fermi-GBM detection
- Swift Trigger 1125354 (GRB 220926A) is not a GRB
- Swift GRB 220926A: Global MASTER-Net observations report
- Analysis of long GRB 220926B detected by INTEGRAL
- GRB 220926B
- GRB 220926A: Swift detection of a burst
- Fermi GRB 220925A: Global MASTER-Net observations report
- GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220921A: further MeerLICHT observations
- GRB 220925A: Fermi GBM Final Real-time Localization
- GRB 220924A: Fermi GBM Final Real-time Localization
- GRB 220921A: ALMA detection
- GRB 220921A: DDOTI Detection of the Afterglow
- Konus-Wind detection of GRB 220921A
- GRB 220921A: Fermi GBM detection
- GRB 220921A: MeerLICHT afterglow observations
- GRB 220921A: Swift-XRT Observations
- GRB 220921A: MASTER OT inside Fermi-LAT error-box
- GRB 220921A: Fermi-LAT detection
- GRB 220921A: Tiled Swift observations
- Improved IPN error box for GRB 220910A
- GRB 220909A: Fermi GBM observation
- Konus-Wind detection of GRB 220910A
- GRB 220910B: Fermi GBM Final Localization
- Fermi GRB 220912A: Global MASTER-Net observations report
- GRB 220910A: Fermi GBM observation
- IPN triangulation of GRB 220910A (bright/long)
- GRB 220912A: AstroSat CZTI detection
- GRB 220831A: DECam optical counterpart follow-up
- GRB 220909A: Swift-XRT observations
- GRB 220912A: Fermi GBM Final Real-time Localization
- IPN triangulation of GRB 220905A
- GRB 220909A: Swift ToO observations
- GRB 220909A: Swift/BAT-GUANO candidate arcminute localization
- GRB 220831A: Gemini-South Infrared Observations
- GRB 220910A: AstroSat CZTI detection
- GRB 220910A: AGILE detection
- GRB 220909A: Fermi GBM Final Real-time Localization
- GRB 220907A: Swift-BAT refined analysis
- GRB 220831A: Gemini-South/GMOS detection of potential optical counterpart
- IPN triangulation of GRB 220903A (long)
- GRB 220907A: Fermi GBM observation
- GRB 220907A: Nanshan/NEXT optical upper limits
- GRB 220907A: Swift/UVOT Upper Limits
- GRB 220907A: Swift-XRT refined Analysis
- GRB 220831A: ATCA 5/9 GHz radio observations
- GRB 220907A: Swift-XRT position
- GRB 220907A: Swift detection of a burst
- GRB 220907A: Fermi GBM Final Real-time Localization
- GRB 220831A: Swift-UVOT Upper Limits
- Fermi GRB 220905A: Global MASTER-Net observations report
- GRB 220905A: BALROG localization (Fermi Trigger 684070128 / GRB 220905478)
- GRB 220905A: Fermi GBM Final Real-time Localization
- GRB 220831A: DECam detection of a possible optical counterpart