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"16 results found.
- GRB 250317B: Mondy AZT-33IK Continued Optical Observations
- GRB 250317B: SVOM/COLIBRI (F-GFT) follow-up observations
- GRB 250317B: OHP/T193 continued follow-up
- GRB 250317B: Leavitt Observatory optical upper limit
- GRB 250317B: Mondy AZT-33IK Optical Observations
- GRB 250317B: NOT optical observations suggest an optical plateau phase
- GRB 250317B: GTC/OSIRIS+ spectroscopic redshift z=3.44
- GRB 250317B: OHP/T193 optical observations
- GRB 250317B: REM optical/NIR observations
- GRB 250317B: Swift-XRT observations
- EP 250317B: Fading optical counterpart detection by LCO
- GRB 250317B: LCO detection of the fading optical afterglow
- GRB 250317B: refined SVOM/MXT analysis
- GRB 250317B: SVOM/F-GFT (COLIBRÍ) Detection of a Fading Optical Counterpart
- GRB 250317B: SVOM detection of a burst / correction to GRB name of GCN 39752
- GRB 250317B: SVOM detection of a burst