Skip to main content
GCN at AAS 245, Legacy Circulars Address Retirement. See news and announcements

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').

17956 results found.

  1. GRB050124: No Swift UVOT Detection of Afterglow Emission
  2. GRB 050117a: Radio Observations
  3. GRB050124,optical observation
  4. GRB050124: Updated Swift XRT Position and Fluxes
  5. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  6. GRB050124: Refined BAT position, spectral and fluence information
  7. GRB050124: Swift-BAT position of a double-peaked burst
  8. GRB050117a: Radio Observations
  9. GRB050117a: Refined analysis
  10. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  11. GRB050117b: Swift-BAT detection of a weak burst
  12. GRB050117: optical observation
  13. GRB 050117, I-band observations
  14. GRB 050117: Optical observation
  15. GRB050117: Refined XRT position
  16. GRB050117: MASTER optical observations
  17. MASTER:GRB050117 SWIFT
  18. GRB050117: Swift-BAT detection of a long multi-peaked burst
  19. GRB050117: Swift XRT Position
  20. SGR1806-20: Swift-BAT observations of two additional bursts
  21. SGR 1806-20, RHESSI observations of the 041227 giant flare
  22. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  23. GRB 041217: Optical observations
  24. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  25. GRB041228: ROTSE-III Optical Observations
  26. GRB041228: Swift-BAT detection of a burst
  27. GRB041219; RXTE ASM Observations
  28. NIR Observations of GRB 041219
  29. GRB041226: ROTSE-III Optical Observations
  30. GRB041226: Swift-BAT detection of a burst
  31. GRB041223: decay of the afterglow
  32. GRB041224: ROTSE-III Optical Observations
  33. GRB 041223: XRT afterglow spectrum and light curve
  34. GRB 041223 Fluence measured by Swift-BAT
  35. GRB041224: Swift-BAT detection of a soft burst
  36. GRB041223: optical and NIR observations with REM
  37. Swift-BAT Time History of GRB041219
  38. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  39. GRB041223: ROTSE-III Optical Observations
  40. GRB041223: Swift-BAT detection of a bright long burst
  41. GRB041220: Swift-BAT burst
  42. GRB 041219 Optical Observations
  43. GRB041219c: Third Burst in One Day from Swift-BAT
  44. GRB041219b: A Swift-BAT burst
  45. Swift-BAT detection of the bright long burst GRB041219
  46. GRB041217: optical limit 30 min after GRB
  47. GRB041217: Optical Observations
  48. GRB041217: NIR and optical observations with REM
  49. GRB041217: P60 Optical Observations
  50. GRB041217: Infrared Observations
  51. GRB041217: The First GRB Located On-Board Swift
  52. GRB040916: Optical observations
  53. GRB040422: optical and NIR observations at the VLT
  54. GRB040223, improved XMM position
  55. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  56. SAX J0840.7+2248 Optical Observations

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov