Skip to main content
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. 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').

13 results found.

  1. GRB 230216A Mondy Observations
  2. GRB 220306B: Swift/UVOT Upper Limits
  3. GRB 220306B: Nanshan/NEXT optical upper limit
  4. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  5. GRB 220306B: Tautenburg observations
  6. GRB 220306B: Swift-BAT refined analysis
  7. GRB 220306B: AbAO optical observations, possible afterglow candidate
  8. GRB 220306B: BOOTES-1 optical upper limit
  9. GRB 220306B: Swift-XRT refined Analysis
  10. GRB 220306B: Fermi GBM observation
  11. GRB 220306B: Enhanced Swift-XRT position
  12. Swift GRB 220306B: Global MASTER-Net observations report
  13. GRB 220306B: Swift detection of a burst


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