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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"

26 results found.

  1. GRB 250424A: VIRT Optical Upper Limit
  2. GRB 250424A: COLIBRÍ detection of the associated supernova
  3. GRB 250424A: CALET Gamma-Ray Burst Monitor detection
  4. GRB 250424A: LCO optical observation
  5. GRB 250424A: Swift-BAT refined analysis
  6. GRB 250424A: SVOM/GRM observation of a long burst
  7. GRB 250424A: PRIME near-infrared detection
  8. GRB 250424A: WINTER J-band detection
  9. GRB 250424A: EIRSAT-1 GMOD Detection
  10. GRB 250424A: SVOM/VT optical observation
  11. GRB 250424A: Swift/UVOT Detection
  12. Konus-Wind detection of GRB 250424A
  13. GRB 250424A: Skynet Optical Observations
  14. GRB 250424A: Kilonova-Catcher optical afterglow detection
  15. GRB 250424A: Swift-XRT refined Analysis
  16. GRB 250424A: Enhanced Swift-XRT position
  17. GRB 250424A: AstroSat CZTI detection of a bright long burst
  18. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  19. GRB 250424A: BlackGEM optical afterglow detection
  20. GRB 250424A: VLT/X-shooter spectroscopic redshift z = 0.310
  21. GRB 250424A: likely host galaxy
  22. GRB 250424A: DDOTI Afterglow Detection
  23. GRB 250424A: REM optical/NIR afterglow detection
  24. GRB 250424A: Swift detection of a burst with an optical counterpart
  25. Swift GRB 250424A: Global MASTER-Net observations report
  26. Swift GRB 250424A: Global MASTER-Net OT detection

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