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').

10 results found.

  1. GRB 100915 optical upper limit
  2. GRB 100915A: TAROT Calern observatory optical observations
  3. GRB100915A: MITSuME Ishigakijima Optical upper limits
  4. GRB 100915A: GRT Optical Observation
  5. GRB 100915A: Correction to Swift-BAT refined analysis
  6. GRB 100915A: Swift/UVOT Upper Limits
  7. GRB 100915A: Swift-BAT refined analysis
  8. GRB 100915A: Swift-XRT refined analysis
  9. GRB 100915A: Enhanced Swift-XRT position
  10. GRB 100915A: Swift detection of a likely burst


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