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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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').
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"

4 results found.

  1. GRB 250527C: CrAO Optical Upper Limit
  2. GRB 250527C: Swift/UVOT Upper Limits
  3. GRB 250527C: Swift ToO observations
  4. GRB 250527C: Swift/BAT-GUANO arcminute localization of a burst

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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