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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"

12 results found.

  1. GRB 150727A: IRSF NIR observation
  2. GRB 150727A: Continued RATIR Optical Observations - Fading
  3. GRB 150727A: RATIR Optical Observations
  4. GRB 150727A: Swift-BAT refined analysis
  5. GRB 150727A: Watcher optical upper limit
  6. GRB 150727A: Swift/UVOT Detection
  7. GRB 150727A: LCOGT-Cerro Tololo observations
  8. GRB 150727A: Swift-XRT refined Analysis
  9. GRB 150727A: Fermi GBM detection
  10. GRB 150727A: VLT/X-shooter redshift
  11. GRB 150727A: Enhanced Swift-XRT position
  12. GRB 150727A: Swift detection of a burst with an optical counterpart

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Download all Circulars as a .tar.gz archive:
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