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"
6094 results found.
- GRB 240306A: Fermi GBM observation
- Konus-Wind detection of GRB 231118A
- GRB 240305A: Fermi GBM observation
- Fermi-LAT gamma-ray observations of IceCube-240229A
- GRB 240305C: AstroSat CZTI detection of a short burst
- GRB 240303B: Fermi GBM Detection
- GRB 240225B: Swift-XRT afterglow detection
- GRB 240215A: Swift-XRT afterglow detection
- GRB 240225B: further SAO RAS optical observations
- Konus-Wind detection of GRB 240225B (long)
- GRB 240225B: SAO RAS optical observations
- GRB 240225B: NOT optical observations
- GRB 240225B: Swift-XRT observations
- Transient EPW20240219aa: Kp-band imaging observations with NIRES
- Swift BAT Sub-Threshold Detection of EPW20240219aa
- GRB 240222A: Swift-XRT refined Analysis
- GRB 240222A: Fermi GBM Observation
- GRB 240215B: Fermi GBM Observation
- GRB 240218A: LBT H-band detection
- Konus-Wind detection of GRB 240218A
- GRB 240218A: Swift-XRT refined Analysis
- GRB 240218A: Fermi GBM Detection
- GRB 240215A: Fermi GBM Observation
- Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
- GRB 240209A: Fermi GBM observation
- GRB 240128A: Further Swift-XRT observations
- Fermi-LAT gamma-ray observations of IceCube-240204A
- GRB240204A: Swift/UVOT Upper Limits
- Konus-Wind detection of GRB 240205B (long / very soft)
- GRB 240205B: Fermi GBM Observation
- GRB 240204A: Fermi GBM Observation
- GRB 240129A: Fermi GBM Observation
- GRB 240128A: Swift-XRT observations
- GRB 240123B: Fermi GBM Observation
- Fermi-LAT gamma-ray observations of IceCube-240123A
- GRB 240123A: further SAO RAS optical observations
- GRB 240123A: SAO RAS optical observations
- GRB 240122A: Swift/UVOT Upper Limits
- GRB 240123A: Swift-XRT refined Analysis
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240118A: Swift-XRT afterglow detection
- GRB 240118C: Fermi GBM Observation
- GRB 240115A: Fermi GBM Observation
- GRB 240118A: Fermi GBM Observation
- GRB 240118A: Fermi-LAT detection
- GRB 240115B: Fermi GBM Detection
- GRB 240112C: Fermi GBM Detection
- GRB 240112C: Swift-XRT refined Analysis
- GRB 240109A: Fermi GBM Observation
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
- GRB GRB240101C: Fermi GBM observation
- GRB 240101A: 1.3m DFOT optical observations
- GRB 240102A: 1.3m DFOT optical upper limit
- GRB 240101B: 1.3m DFOT optical upper limit
- GRB 231220A: Swift-UVOT upper limit
- GRB 240101B: Swift-XRT refined Analysis
- GRB 240102A: Swift-XRT refined Analysis
- GRB 240101A: Swift-XRT refined Analysis
- GRB231230A: Fermi GBM Observation
- GRB 231230A: Swift-XRT refined Analysis
- GRB 231210B: BOOTES-7 optical upper limit
- GRB 231222B: Swift-XRT afterglow detection
- GRB 231222B: Fermi GBM Detection
- GRB 231222B: Fermi-LAT detection
- GRB 231220A: Swift-XRT follow-up observations
- GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
- GRB 231214B: Fermi GBM observation
- GRB 231216A: Swift-XRT refined Analysis
- GRB 231216A: GIT optical upper limit
- Konus-Wind detection of GRB 231215A
- GRB 231215A: Fermi GBM observation
- GRB 231215A: Swift-XRT refined Analysis
- GRB 231214A: Fermi GBM observation
- Konus-Wind detection of GRB 231210B
- GRB 231214A: Swift-XRT refined Analysis
- GRB 231214A: Fermi-LAT detection
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
- GRB 231210B: Swift-XRT refined Analysis
- GRB 231205B: 1.3m DFOT Optical upper limit
- GRB 231205B: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-231202A
- Fermi-LAT daily aperture light curve of T CrB now available
- GRB 231203A: Fermi GBM Observation
- GRB 231129C: Swift-XRT afterglow detection
- GRB 231129B: Swift-XRT observations
- GRB 231129C: Fermi-LAT detection
- GRB 231129C: Swift-XRT observations
- GRB 231129C: Fermi GBM Observation of a very bright GRB
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129A: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-231125A
- GRB 231123C: Fermi GBM Observation
- GRB 231123B: Fermi GBM Observation
- GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
- GRB 231115A: XMM-Newton observation
- GRB 231117A: Chandra afterglow detection
- GRB 231117A: GTC Near-Infrared Observations
- GRB 231118B: Fermi GBM observation
- GRB 231118A: Fermi GBM observation
- GRB 231117A: Swift-XRT refined Analysis