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"

20 results found.

  1. GRB 230723B: Swift-BAT refined analysis
  2. GRB 230723B: MITSuME Ishigaki optical observation
  3. GRB 230723B: Further CAHA observations and host galaxy detection
  4. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  5. GRB 230723B: ATCA rapid radio follow-up
  6. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  7. GRB 230723B: Leavitt Observatory upper limit
  8. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  9. GRB 230723B: Montarrenti Observatory upper limit
  10. GRB 230723B: Optical afterglow candidate from CAHA
  11. GRB 230723B: Bassano Bresciano Observatory upper limit
  12. GRB 230723B: Fermi GBM observation
  13. GRB 230723B: Swift-XRT refined Analysis
  14. GRB 230723B: non-detections from Observatoire de Haute-Provence
  15. GRB 230723B: Optical limit from CAHA
  16. GRB 230723B: Swift/UVOT Upper Limits
  17. Swift GRB 230723B: Global MASTER-Net observations report
  18. Swift-XRT position for GRB 230723B
  19. GRB 230723B: Swift-XRT observations
  20. GRB 230723B: Swift detection of a burst

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