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"

24930 results found.

  1. GRB980326 X-ray Observations
  2. GRB980326, optical observations
  3. GRB980326, optical observations
  4. GRB980329, Fading IR counterpart to radio source
  5. GRB980329 Keck K-band observations
  6. GRB980329 sub-millimeter observations
  7. GRB980329 optical observations
  8. GRB980329 near-IR observations
  9. GRB980329 near-IR observations
  10. GRB980326 optical observations
  11. GRB980329 optical observations
  12. GRB980329 VLA observations
  13. GRB980329 optical observations
  14. GRB980329 optical observations
  15. GRB980326 optical observations
  16. GRB980326 optical observations
  17. Optical Observations of GRB 970508
  18. Near-IR follow-up on GRB 971227
  19. Optical Observations of the GRB 971227 field
  20. Optical Observations on GRB 971227
  21. GRB971227: Plaskett R-band observations
  22. GRB 971227: Optical clarifications
  23. GRB971227: Further CAHA R-band images
  24. GRB971227: LOTIS observations
  25. GRB971214: Optical Observations and Calibrations
  26. GRB 971214: Optical Observations
  27. Radio Observations of GRB 971214 at the VLA
  28. GRB 971024: Refined analysis by USNOFS Observations
  29. GRB 971024: KPNO Optical Observations
  30. GRB 970828: Palomar Observations

Advanced

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