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.

Advanced Search Examples (click to copy):

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

21 results found.

  1. EP241217a: VLA Radio Detection

  2. EP241217A: J band upper limit by SYSU 80cm telescope
  3. EP241217a: e-MERLIN radio observations
  4. EP241217a: Liverpool Telescope optical upper limit
  5. EP241217a : Leavitt Observatory optical upper limit
  6. EP241217a: 1.6m Mephisto multi-band optical observations
  7. EP241217a: optical upper limit with the Liverpool Telescope
  8. EP241217a: refined EP-WXT analysis and EP-FXT follow-up observations
  9. EP241217a: REM optical/NIR upper limits
  10. EP241217a: Liverpool Telescope optical follow-up
  11. EP241217a: NOT optical observations
  12. EP241217a: GROWTH-India Telescope optical observations
  13. EP241217a: Xinglong optical follow-up observations
  14. EP241217a: Global MASTER-Net observations report
  15. EP241217a: Swift-XRT Detection
  16. EP241217A: Non-detection from Fermi-GBM Observations
  17. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  18. EP241217a: Kinder optical follow-up observations
  19. EP241217A: LCO optical observations
  20. EP241217a: Gemini-North detection of the likely optical counterpart
  21. EP241217a: EP detection of an X-ray transient

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