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"10 results found.
- GRB 250329B: Swift/UVOT Upper Limit
- GRB 250329B: CAHA 2.2m telescope optical limit
- GRB 250329B: Swift-XRT confirmation of fading
- GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
- GRB 250329B: Swift-XRT afterglow detection
- GRB 250329B: SVOM/C-GFT optical upper limit
- GRB 250329B: SVOM/VT optical upper limit
- GRB 250329B: 1.6m Mephisto Optical Upper Limits
- GRB 250329B: GWAC-F50A optical upper limit
- GRB 250329B: SVOM detection of a faint transient