Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

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').

12 results found.

  1. GRB 231214A: ATCA Radio Upper Limits
  2. GRB 231214A: Swift-BAT refined analysis
  3. GRB 231214A: Swift/UVOT Upper Limits
  4. GRB 231214A: Fermi GBM observation
  5. GRB 231214A: REM optical/NIR upper limits
  6. GRB 231214A: Swift-XRT refined Analysis
  7. GRB 231214A: AstroSat CZTI detection
  8. GRB 231214A: Fermi-LAT detection
  9. GRB 231214A: Enhanced Swift-XRT position
  10. GRB231214A: BOOTES-6/DPRT optical upper limit
  11. GRB 231214A: Swift detection of a burst
  12. GRB 231214A: Fermi GBM Final Real-time Localization


Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit