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"

22 results found.

  1. GRB 241029A: LCO optical observation
  2. GRB 241029A: AbAO AS-32 optical observations
  3. GRB 241029A: GRBAlpha detection
  4. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  5. GRB 241029A: LCO optical detection
  6. GRB 241029A: SVOM/VT optical afterglow observations
  7. GRB 241029A: GROWTH-India Telescope optical follow up
  8. GRB 241029A: SAO RAS optical observations
  9. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  10. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  11. GRB 241029A: Swift-XRT observations
  12. GRB 241029A: Fermi GBM Observation
  13. GRB 241029A: AKO Optical Afterglow Detection
  14. GRB 241029A: GOTO optical afterglow detection
  15. GRB 241029A: MASTER early optical counterpart detection
  16. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  17. GRB 241029A: Mephisto observations
  18. GRB 241029A: TRT optical afterglow candidate detection
  19. GRB 241029A: Swift ToO observations
  20. GRB 241029A: SVOM/GRM observation
  21. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  22. GRB 241029A: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov