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 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
- GRB 251026B: LBT near-infrared observations
- GRB 251026B: Fermi GBM Observation
- GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
- GRB 251026B: Swift ToO observations
- GRB 251026B: Tentative GOTO optical counterpart candidate
- Fermi GRB 251026B: Global MASTER-Net observations report
- GRB 251026B: Fermi GBM Final Localization