Skip to main content
New! BOOM Notices and Schema v7.0.0. 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').
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"

218 results found.

  1. GRB 030227 optical afterglow
  2. GRB 030227: Confirmed Optical Afterglow (S1-A)
  3. GRB 030227: fading of candidate optical afterglow 'S1-A'
  4. GRB 030227, possible optical counterpart of XMM-Newton source
  5. GRB030227 - faint tentative OT candidate
  6. XMM-Newton observation of GRB030227
  7. GRB020410: BeppoSAX NFI observations refined analysis
  8. X-ray afterglow of GRB020321
  9. GRB 020322: BeppoSAX observations of the X-ray afterglow
  10. Near-Infrared Observations of GRB020322 at TIRGO
  11. GRB 020322 optical observation
  12. GRB 020322: Optical Sources and Improved Astrometry
  13. GRB020322, optical observations
  14. GRB 020322: Optical candidate
  15. XMM-Newton observation of GRB020322
  16. XMM-Newton observation of GRB011211
  17. CORRECTION to XMM-Newton observation of GRB001025
  18. XMM-Newton observation of GRB001025

Advanced

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