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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"

20 results found.

  1. GRB 250205A / EP250205A: further radio observations with the VLA
  2. GRB 250205A: VIRT Optical Upper Limit
  3. GRB 250205A: Leavitt Observatory optical upper limit
  4. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  5. GRB 250205A / EP250205A: radio detection with the VLA
  6. GRB 250205A: 1.3m DFOT optical upper limit
  7. GRB 250205A: Fermi GBM Observation
  8. GRB 250205A: REM NIR upper limit
  9. EP250205a/GRB 250205A: FTW optical and NIR observations of the counterpart
  10. GRB 250205A: Swift/UVOT Upper Limits
  11. EP250205a/GRB 250205A: correction to the source localization
  12. EP250205a/GRB 250205A: Einstein Probe observation
  13. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  14. GRB 250205A: Swift/XRT detection
  15. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  16. GRB250205A: SVOM/VT optical afterglow detection
  17. GRB 250205A: GOTO optical upper limits
  18. GRB 250205A: OHP/T193 optical counterpart candidate
  19. GRB 250205A: Liverpool Telescope optical counterpart candidate detection
  20. GRB 250205A: SVOM detection of a burst

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