Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

9 results found.

  1. GRB 140824A: optical upper limit in CrAO
  2. GRB 140824A: NOT optical upper limits
  3. GRB 140824A: OSN optical limit
  4. GRB 140824A: Swift-XRT refined Analysis
  5. GRB 140824A: Swift-BAT refined analysis
  6. GRB 140824A: Enhanced Swift-XRT position
  7. GRB 140824A: MITSuME Ishigakijima upper limits
  8. GRB 140824A: Swift/UVOT Upper Limits
  9. GRB 140824A: Swift detection of a burst

Advanced

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