Skip to main content
Circulars over Kafka event name backfill. 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.

Lucene Examples (click to copy):

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

24 results found.

  1. Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
  2. GRB 061121, SMARTS optical/IR observations
  3. GRB 061121: flattening of the decay
  4. GRB 061121: Second Epoch ATCA Radio Observations
  5. GRB 061121: ATCA & WSRT Radio Observations
  6. GRB 061126: Swift/UVOT Observations
  7. GRB 061121: MDM Continued Monitoring
  8. GRB 061121: MDM Continuing Optical Decay
  9. GRB 061121: Ep,i - Eiso correlation
  10. GRB 061121: MDM Optical Decay
  11. GRB 061121: ART detection in Ic
  12. GRB061121: P60 Observations
  13. Radio detection of GRB 061121
  14. GRB 061121: MDM Optical Observations
  15. GRB 061121 declared "Burst of Interest" by Swift team
  16. Konus-Wind and Konus-A observations of GRB 061121
  17. GRB 061121: Swift/UVOT Observations
  18. GRB 061121: Swift-XRT Team Refined Analysis
  19. GRB 061121, Swift-BAT refined analysis
  20. GRB 061121 : Planned XMM-Newton observation
  21. GRB 061121: Optical observation at the KANATA 1.5m telescope
  22. GRB 061121: Faulkes Telescope North Optical Observation
  23. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  24. GRB 061121: Swift detection of a bright burst with an optical counterpart

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