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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"

30 results found.

  1. Gagarin-day GRB 200412B: observations with the 3.6m Devasthal Optical Telescope
  2. GRB 200412B: continued Mondy and Terskol optical observations
  3. GRB 200412B: continued Terskol optical observations
  4. GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
  5. GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
  6. GRB 200412B: continued Tautenburg observations
  7. GRB 200412B: Mondy optical observations
  8. GRB 200412B: continued Tautenburg observations
  9. Konus-Wind observation of GRB 200412B
  10. GRB 200412B: MITSuME Akeno optical observation
  11. GRB 200412B: Tautenburg observations
  12. GRB 200412B: contunued AbAO optical observations
  13. GRB 200412B: CALET Gamma-Ray Burst Monitor detection
  14. GRB 200412B: Xinglong TNT optical observations
  15. GRB 200412B: SAO RAS observations of OT
  16. GRB 200412B: Tautenburg observations
  17. GRB 200412B: AbAO optical observations
  18. GRB 200412B: Insight-HXMT/HE detection
  19. GRB 200412B: Optical afterglow detection with 1.3m DFOT
  20. GRB 200412B : AstroSat CZTI detection
  21. GRB 200412B: Swift-XRT afterglow detection
  22. GRB 200412B: Fermi GBM detection
  23. GRB 200412B: Fermi-LAT detection
  24. GRB 200412B: MASTER-Amur Optical Couterpart in Gagarin day!
  25. GRB 200412B: MASTER Optical Couterpart in Gagarin day!
  26. Correction to GCN 27551 - Swift is observing GRB 200412*B*
  27. GRB 200412B: Tiled Swift observations
  28. Fermi GRB 200412B: Global MASTER-Net observations report
  29. GRB 200412B: BALROG localization (Fermi Trigger 608375325 / GRB 200412381)
  30. GRB 200412B: Fermi GBM Final Real-time Localization

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