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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"

5819 results found.

  1. Lowell/Perkins observation of GRB 991216
  2. GRB 990806, Optical Observations
  3. Updated Astrometry for the IR Counterpart of GRB990705
  4. GRB 990705, R-band observations
  5. IPN localization of GRB990705
  6. Infrared and Optical Observations of GRB990705
  7. GRB 990705, radio observations
  8. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  9. GRB990704, optical observations
  10. GRB990323 PRECISE IPN POSITION
  11. GRB 990316, Optical observations
  12. On the Lensing Interpretation of GRB 990123
  13. GRB990123, early optical counterpart detection
  14. GRB 981220 Optical observations
  15. GRB981220 B, R and I band observations
  16. GRB 981220:Optical Observations
  17. GRB980703 optical photometry
  18. GRB980703 optical followup
  19. SGR1900+14 field optical observations

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Download all Circulars as a .tar.gz archive (updated once a day):
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