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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"

14 results found.

  1. GRB 050416(a): Host Galaxy Redshift Determination
  2. GRB 050416: Optical/NIR observations
  3. GRB 050416: Mitsume optical observation
  4. GRB 050416 : optical observation at Xinglong observatory
  5. GRB 050416: Swift/UVOT refined analysis
  6. GRB 050416: Swift/UVOT detection of afterglow emission
  7. GRB 050416: Swift-BAT refined analysis
  8. GRB 050416: ART observations
  9. GRB 050416,optical observation
  10. GRB 050416: KAIT observations
  11. GRB 050416: Swift XRT Position
  12. GRB 050416: Radio observations
  13. Confirmation of OT for GRB050416
  14. Swift BAT/XRT Detection of GRB 050416

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Download all Circulars as a .tar.gz archive:
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