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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"

32 results found.

  1. GRB 211023A: OAJ Bright Afterglow Confirmation
  2. GRB 181201A: photometric signature of the SN
  3. GRB 181201A: continued optical observations in Mondy
  4. GRB 181201A: VLA detection
  5. GRB 181201A: ALMA detection of a fading mm afterglow
  6. GRB 181201A: continued optical observations in TSHAO and Chilesope
  7. GRB 181201A: continued optical observations in TSHAO
  8. GRB 181201A: Continued GROND observations show that afterglow is still bright
  9. GRB181201A: GOTO optical observations
  10. GRB 181201A: AstroSat CZTI detection
  11. GRB 181201A: Swift/UVOT Detection
  12. GRB 181201A: continued optical observations in SAAO and Chilesope
  13. Konus-Wind observation of GRB 181201A
  14. GRB 181201A: Further COATLI Optical Monitoring
  15. GRB 181201A: Insight-HXMT/HE detection
  16. GRB 181201A: VLT/FORS2 tentative spectroscopic redshift
  17. GRB 181201A: GROND detection of the afterglow and redshift upper limit of z < 3
  18. GRB 181201A: optical observations in Chilescope observatory
  19. GRB 181201A: Global MASTER-Net prompt optical descovery and afterglow observations
  20. GRB 181201A: COATLI Optical Detection
  21. GRB 181201A: Fermi-LAT detection
  22. GRB 181201A: Zeiss-1000/CrAO optical observations
  23. GRB 181201A: NOT optical observations
  24. GRB 181201A: optical observations in SAAO
  25. GRB 181201A MASTER-Net OT continued observation
  26. GRB 181201A: iTelescope optical afterglow detection
  27. GRB 181201A: Swift-XRT afterglow detection
  28. GRB 181201A: Swift ToO observations
  29. GRB 181201A: Swift-XRT afterglow
  30. GRB 181201A: likely Swift/XRT afterglow
  31. GRB 181201A MASTER-Net OT detection
  32. GRB 181201A: a long GRB detected by INTEGRAL

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