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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"

23 results found.

  1. GRB 250625A: VLT/X-shooter spectroscopic observations at the afterglow position
  2. GRB 250625A: Swift-BAT refined analysis
  3. GRB 250625A: Leavitt Observatory afterglow detection
  4. GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
  5. GRB 250625A: GTC/OSIRIS+ spectroscopic observations of the potential host galaxy
  6. GRB 250625A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  7. GRB 250625A: SVOM/C-GFT upper limit in early phase
  8. GRB 250625A: GECAM-B detection
  9. GRB 250625A: Swift/UVOT Upper Limits
  10. GRB 250625A: ABObservatory afterglow detection
  11. GRB 250625A: OHP/T193 optical detection
  12. GRB 250625A: COLIBRÍ optical observations
  13. GRB 250625A: Fermi-LAT detection
  14. GRB 250625A: Swift-XRT refined Analysis
  15. GRB 250625A: JinShan optical observations
  16. Swift GRB 250625A: Global MASTER-Net observations report
  17. GRB 250625A: NOT z-band upper limit
  18. GRB 250625A: SVOM/VT optical confirmation
  19. GRB 250625A: SAO RAS possible optical afterglow
  20. GRB 250625A: Enhanced Swift-XRT position
  21. Fermi GRB 250625A: Global MASTER-Net observations report
  22. GRB 250625A: Swift detection of a burst
  23. GRB 250625A: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive:
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