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').

12 results found.

  1. GRB 210217A: 3.6m DOT optical observations
  2. GRB 210217A: Mondy optical observations
  3. GRB 210217A: Swift/UVOT Detection
  4. GRB 210217A: 1.3m DFOT optical detection
  5. GRB 210217A: Swift-XRT refined Analysis
  6. Fermi GBM Sub-Threshold Detection of GRB 210217A
  7. GRB 210217A: Liverpool Telescope First Hour Observations
  8. GRB 210217A: Swift-BAT refined analysis
  9. GRB 210217A: KAIT Optical Observations
  10. GRB 210217A: Enhanced Swift-XRT position
  11. GRB 210217A: NEXT early optical afterglow observations
  12. GRB 210217A: Swift detection of a burst with an optical counterpart


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