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"8 results found.
- GRB 250509A: Fermi GBM Observation
- GRB 250509A: Swift-XRT refined Analysis
- GRB 250509A: Enhanced Swift-XRT position
- GRB 250509A: Prompt enhanced Swift-XRT position
- Fermi GRB 250509A: Global MASTER-Net observations report
- Swift GRB 250509A: Global MASTER-Net observations report
- GRB 250509A: Swift detection of a burst
- GRB 250509A: Fermi GBM Final Real-time Localization