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"14 results found.
- EP250427a / GRB 250427A: OHP/T193 photometric observations: third visit
- EP 250427A: Optical counterpart detection by LCO.
- EP250427a / GRB 250427A: OHP/T193 continued photometric observations
- GRB 250427A: Swift/UVOT Detection
- EP250427a / GRB 250427A: OHP/T193 photometric observations
- EP250427a: EP-FXT follow-up observations
- EP250427a/GRB 250427A: FTW optical and NIR observations of the counterpart
- GRB250427A/EP250427a GIT optical afterglow detection:
- GRB 250427A: Swift-XRT refined Analysis
- EP250427a / GRB 250427A: LCO optical counterpart detection
- EP250427a / GRB 250427A: VLT/X-shooter redshift confirmation z = 1.520
- EP250427A/GRB250427A: Keck/LRIS redshift
- GRB 250427A/ EP250427a: Fermi-GBM Sub-Threshold Detection
- EP 250427a: BOOTES-7 optical afterglow candidate