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 230320B: Fermi GBM Observation
- GRB 230322B: Swift-XRT refined Analysis
- GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
- GRB 230307A: Swift/UVOT detection
- GRB 230307A: Swift-XRT afterglow detection
- Alert from the HAWC Burst Monitor HAWC-230311A
- GRB 230308A: Fermi GBM detection
- GRB 230307A: ASO-S/HXI detection
- GRB 230228A: NUTTelA-TAO / BSTI Optical Limits
- GRB 230307A: Swift/BAT upper limits on the early afterglow
- GRB 230307A: Swift-XRT observations
- GRB 230307A: AstroSat CZTI detection
- Fermi-LAT gamma-ray observations of IceCube-230306A
- GRB 230228A: Swift-XRT refined Analysis
- GRB 230217A: Swift/UVOT Upper Limits
- GRB 230217A: Swift-XRT afterglow detection
- Fermi-LAT gamma-ray observations of IceCube-230220A
- GRB 230217A: Gemini-South Optical Observation
- GRB 230217A: Fermi GBM observation
- Fermi-LAT gamma-ray observations of IceCube-230217A
- GRB 230217A: Swift-XRT observations
- GRB 230216A: Swift-XRT refined Analysis
- GRB 230209B: Fermi GBM Observation
- Swift Trigger 1153670 is probably not a GRB
- GRB 221009A: Continued Swift Observations
- GRB 230204B: Swift/UVOT Upper Limits
- GRB 230204B: Fermi GBM detection
- GRB 230204B: Swift-XRT afterglow detection
- GRB 230205A: Swift-XRT refined Analysis
- GRB 230204B: GIT discovery of the likely optical afterglow
- GRB 230204A: Swift-XRT refined Analysis
- ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
- Fermi-LAT gamma-ray observations of IceCube-230201A
- GRB 230129A: AstroSat CZTI detection
- GRB 230124A: Fermi GBM Observation
- Fermi-LAT gamma-ray observations of IceCube-230122A
- GRB 230123A: Swift-XRT refined Analysis
- GRB 230116C: Swift-XRT observations
- GRB 230116B: Fermi GBM observation
- GRB 230116D: 3.6m DOT optical upper limit
- GRB 230116D: SAO RAS further observations
- GRB 230116D: Swift-XRT refined Analysis
- GRB 230116D: GIT optical follow-up
- GRB 230116C: Swift detection of a burst
- Fermi-LAT gamma-ray observations of IceCube-230112A
- Fermi-LAT Gamma-ray Observations of IceCube-Cascade-230109A
- Fermi-LAT Gamma-ray Observations of IceCube-Cascade-221229A
- GRB 230111A: Fermi GBM Observation
- GRB 230102A: Fermi GBM Observation
- GRB 221231A: Fermi GBM Observation
- GRB 221231A: Swift-XRT afterglow detection
- GRB 221231A: Swift-XRT observations
- Fermi-LAT gamma-ray observations of IceCube-221229A
- GRB 221226A: Fermi GBM detection
- GRB 221226B: Fermi GBM Observation
- GRB 221226B: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-221224A
- Fermi-LAT gamma-ray observations of IceCube-221223A
- GRB 221218A: 3.6m DOT optical upper limit
- GRB 221215A: Fermi GBM Detection
- Fermi-LAT gamma-ray observations of IceCube-221216A
- GRB 221216A: Fermi GBM observation
- GRB 221216A: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-221210A
- GRB 221215A: Swift-XRT observations
- GRB 221209A: Fermi GBM observation
- GRB 221206B: Fermi GBM observation
- GRB 221206B: Swift-XRT observations
- GRB 221201A: Fermi GBM observation
- GRB 221202A: Swift-XRT refined Analysis
- GRB 221201A: Swift-XRT refined Analysis
- GRB 221126A: Fermi GBM observation
- Alert from the HAWC Burst Monitor HAWC-221128A
- Fermi-LAT gamma-ray observations of IceCube-221124A
- Alert from the HAWC Burst Monitor HAWC-221123A
- GRB 221120A: Fermi GBM observation
- GRB 221120A: Swift-XRT refined Analysis
- GRB 221120A: GIT upper limits on optical afterglow
- GRB 221119A: Fermi GBM detection
- GRB 221119A: Fermi-LAT detection
- GRB 221115A: Fermi GBM detection
- GRB 221110A: Swift-XRT refined Analysis
- GRB 221107A: Fermi GBM Observation
- GRB 221009A: Extended Bad Time Intervals for Fermi LAT data
- Fermi-LAT gamma-ray observations of IceCube-221104A
- GRB 221029A: Fermi GBM observation
- GRB 221028A: Swift-XRT refined Analysis
- GRB 221028A: 1.3m DFOT Optical upper limit
- GRB 221028A: HCT optical upper limit
- GRB 221028A: GIT optical upper limit
- GRB 221027B: Swift-XRT refined Analysis
- GRB 221027A: Fermi GBM detection
- GRB 221027A: Fermi-LAT detection
- GRB 221025A: Fermi GBM Observation
- GRB 221022A: Swift-XRT observations
- GRB 221024A: Swift-XRT refined Analysis
- GRB 221023A: Fermi GBM Observation
- GRB 221025A: Fermi-LAT detection
- GRB 221022A: Fermi GBM detection
- GRB 221023A: Fermi-LAT detection