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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"

44 results found.

  1. GRB 250215A / EP250215A: Encouraging Follow-up Observations of a BdHN I with a Rest-Frame Duration 2.3 s at z=4.61
  2. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  3. GRB 220101A: The first example of a Petanova
  4. GRB 220101A: KAO optical-R observation
  5. GRB 220101A: TSHAO optical observation, Terskol, AbAO upper limits
  6. GRB 220101A: The most powerful GRB and BDHN I in 26 years
  7. GRB 220101A: continued 1.3m DFOT optical observations of a high-redshift afterglow
  8. Konus-Wind detection of GRB 220101A (correction to GCN 31433)
  9. Konus-Wind detection of GRB 220101A
  10. GRB 220101A: Additional Liverpool telescope photometry
  11. GRB 220101A: SAO RAS optical observations
  12. GRB 220101A: Tautenburg observations
  13. GRB 220101A: Continued Mondy optical observations
  14. GRB 220101A: further TNG NIR observations
  15. GRB 220101A: continued 1.3m DFOT Optical Observations
  16. GRB 220101A: Mondy optical observations
  17. GRB 220101A: 3rd LCO Optical Observation
  18. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  19. GRB 220101A: iTelescope optical observations
  20. GRB 220101A: VLA detection
  21. GRB 220101A: 1.3m DFOT observations
  22. GRB 220101A: LCO Continued Optical Observations
  23. GRB 220101A: TNG NIR afterglow detection
  24. GRB 220101A: ALMA detection
  25. GRB 220101A: LCO Optical Observations
  26. GRB 220101A: Tautenburg observations
  27. GRB 220101A: Swift-BAT refined analysis
  28. GRB 220101A: GMG observation (2nd epoch)
  29. GRB 220101A: OASDG optical observations
  30. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  31. GRB 220101A: GMG observation
  32. GRB 220101A: Asiago spectroscopic and photometric detection
  33. GRB 220101A: Fermi GBM Detection
  34. GRB 220101A: NOT redshift confirmation
  35. GRB 220101A: CAHA 2.2m/CAFOS detection
  36. GRB 220101A: Liverpool telescope imaging of a high-redshift afterglow
  37. GRB 220101A: THO optical observations
  38. GRB 220101A: Swift-XRT refined Analysis
  39. GRB 220101A: AGILE detection
  40. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  41. GRB 220101A: Fermi-LAT detection
  42. GRB 220101A: Enhanced Swift-XRT position
  43. GRB 220101A: Correction to GCN 31347
  44. GRB 220101A: Swift detection of a burst with a bright optical counterpart

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