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.
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"26040 results found.
- GRB 221009A: LCOGT Optical Afterglow Detection
- GRB 221009A: COATLI Detection of the Afterglow
- GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger
- GRB 221009A (Swift J1913.1+1946): Swift-BAT refined analysis
- GRB 221009A: 10.4m GTC spectroscopic redshift confirmation
- GRB 221009A: Detection by GRBAlpha
- GRB 221009A: Sintez-Newton/CrAO optical observations
- GRB 221009A: Upper limits from HAWC 8 hours after trigger
- GRB 221006A: Swift ToO observations
- Swift/XRT discovery of multiple dust-scattering X-ray rings around GRB 221009A
- GRB 221009A (Swift J1913.1+1946): iTelescope optical observation
- LHAASO observed GRB 221009A with more than 5000 VHE photons up to around 18 TeV
- GRB 221009A: NOEMA mm detection
- GRB 221009A: Continued Swift/XRT observations
- GRB 221009A/Swift J1913.1+1946: Assy optical afterglow observation
- GRB 221009A/Swift J1913.1+1946: Lick/Nickel telescope optical observations
- GRB 221009A: Lulin SLT-40cm optical observations
- Swift J1913.1+1946: New Photometry
- GRB 221009A: Upper limits from a neutrino search with IceCube
- GRB 221009A (Swift J1913.1+1946): Burke-Gaffney Observatory optical observations
- GRB221009A/Swift J1913.1+1946: SRG/ART-XC observation
- GRB 221009A / Swift J1913.1+1946: GIT detection of the optical afterglow
- GRB221009A/Swift J1913.1+1946: Solar Orbiter STIX measurements
- GRB221009A/Swift J1913.1+1946: INTEGRAL SPI/ACS observations
- GRB 221009A: Multi-color detection of the optical
- GRB 221009A: Fermi-LAT refined analysis
- GRB 221009A (Swift J1913.1+1946): AGILE/GRID detection
- GRB 221009: Swift/UVOT Detection
- GRB221009A/Swift J1913.1+1946: ATA follow-up observations
- GRB 221009A or Swift J1913.1+1946: PRIME near-infrared detection
- GRB 221009A/Swift J1913.1+1946: AMI-LA observations
- GRB 221009A: REM optical and NIR detection of the afterglow
- GRB 221009A: Swift-XRT refined Analysis
- GRB 221009A (Swift J1913.1+1946): AGILE/MCAL detection
- Swift J1913.1+1946: Early Optical Photometry
- 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
- Swift J1913.1+1946 : Pre-discovery limits from ZTF
- 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
- Swift GRB221009.59: Global MASTER-Net OT detection
- GRB 221008A: Swift-XRT observations
- Swift J1913.1+1946 a new bright hard X-ray and optical transient
- GRB 221008A: Tiled Swift observations
- GRB 221006A: Swift-XRT observations
- GRB 221006A: Tiled Swift observations
- GRB 220930A: MITSuME Akeno optical upper limits
- 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
- IPN triangulation of GRB 220927A (long)
- GRB 220921A: LCOGT Optical Observations
- GRB 220611A: Host galaxy redshift from VLT/X-shooter
- GRB 220924A: Fermi GBM detection
- Swift Trigger 1125354 (GRB 220926A) is not a GRB
- Swift GRB220926.34: Global MASTER-Net observations report
- Swift GRB 220926A: Global MASTER-Net observations report
- GRB 220926A: Swift detection of a burst
- GRB 220924A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220921A: further MeerLICHT observations
- Swift GRB220923.47: Global MASTER-Net observations report
- GRB 220921A: DDOTI Detection of the Afterglow
- GRB 220921A: MeerLICHT afterglow observations
- GRB 220921A: Swift-XRT Observations
- GRB 220921A: Fermi-LAT detection
- GRB 220921A: Tiled Swift observations
- GRB 220909A: Fermi GBM observation
- GRB 220831A: DECam optical counterpart follow-up
- GRB 220909A: Swift-XRT observations
- IPN triangulation of GRB 220905A
- GRB 220909A: Swift ToO observations
- GRB 220909A: Swift/BAT-GUANO candidate arcminute 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