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').

17 results found.

  1. GRB 150120B: GMG observation
  2. GRB 150120B: Khureltogot optical observations
  3. GRB 150120B: Mondy optical observations
  4. GRB 150120B: RATIR Optical and NIR Observations
  5. GRB 150120B: FTN early optical light curve
  6. GRB150120B: Xinglong TNT optical observation
  7. GRB 150120B: Swift/UVOT Upper Limits
  8. GRB 150120B, Optical observations
  9. GRB 150120B: GROND Afterglow Detection
  10. GRB 150120B: Additional P60 observations
  11. GRB 150120B: MITSuME Okayama upper limits
  12. GRB 150120B: Swift-BAT refined analysis
  13. GRB 150120B: Swift-XRT refined Analysis
  14. GRB 150120B: Enhanced Swift-XRT position
  15. GRB 150120B: FTN optical afterglow confirmation
  16. GRB 150120B: P60 optical afterglow
  17. GRB 150120B: Swift detection of a burst


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