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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"

11 results found.

  1. GRB 250321A: Swift-BAT refined analysis
  2. GRB 250321A: Swift-XRT refined Analysis
  3. EP 250321A: Optical counterpart detection by LCO.
  4. GRB 250321A: Swift/UVOT Upper Limits
  5. Swift GRB 250321A: Global MASTER-Net observations report
  6. Fermi GRB 250321A: Global MASTER-Net observations report
  7. GRB 250321A: GOTO optical upper limits
  8. GRB 250321A: Swift-XRT localisation
  9. GRB 250321A: Fermi GBM Observation
  10. GRB 250321A: Swift detection of a burst
  11. GRB 250321A: Fermi GBM Final Real-time Localization

Advanced

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