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 201024A: 1.3m DFOT optical observations
  2. GRB 201024A: MITSuME Akeno optical upper limits
  3. GRB 201024A: Swift-BAT refined analysis
  4. GRB201024A: rebrightening after initial steep decline
  5. GRB 201024A: Swift-XRT refined Analysis
  6. GRB 201024A: Swift/UVOT Detection
  7. GRB 201024A: VIRT optical observations
  8. GRB 201024A: Enhanced Swift-XRT position
  9. GRB 201024A: FRAM-ORM afterglow detection
  10. GRB 201024A: Redshift from GTC/OSIRIS
  11. GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
  12. GRB 201024A: MASTER correction to GCN 28760
  13. GRB 201024A: Swift detection of a burst with an optical afterglow


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