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').

22 results found.

  1. GRB 051227 : WIDGET simultaneous optical observations
  2. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  3. GRB051227: SARA Observations
  4. GRB 051227: Likely host galaxy underlying afterglow position
  5. GRB 051227: optical observation
  6. GRB 051227: Confirmed fading from Gemini observations
  7. GRB051227: further analysis of VLT images
  8. GRB 051227: optical afterglow
  9. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  10. GRB 051227: Gemini observations
  11. GRB 051227: Keck Spectroscopy
  12. GRB 051227: Magellan r'-band Imaging/Astrometry
  13. GRB 051227: refined analysis of VLT images
  14. GRB 051227: P60 Observations
  15. GRB 051227: MDM Observation
  16. GRB 051227: R-band object in the XRT error circle
  17. GRB 051227: Joint Swift-HETE Spectral Analysis
  18. GRB 051227: XRT refined analysis
  19. GRB 051227: Further analysis of the Swift-BAT burst
  20. GRB 051227: Refined analysis of the Swift-BAT burst
  21. GRB 051227, optical observation
  22. GRB 051227: Swift detection of a burst


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