Skip to main content
Circulars over Kafka event name backfill. 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').

18291 results found.

  1. GRB 050219a: Refined XRT position
  2. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  3. GRB 050219: Swift-BAT detection of a burst
  4. GRB050215b: Swift UVOT Detection of Afterglow Emission
  5. GRB 050219: Prompt X-ray position
  6. GRB 050215b: XRT confirmation of IR afterglow candidate
  7. GRB050215b: P60 Optical Observations
  8. GRB 050215b: Swift XRT Source Variability
  9. GRB 050215B: candidate afterglow
  10. GRB 050215b : Lulin follow-up observation
  11. GRB 050215b, BOOTES-2 simultaneous optical observations
  12. GRB 050215B: UKIRT K-band imaging
  13. GRB 050215b: Swift XRT Observations
  14. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  15. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  16. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  17. GRB050215B: ROTSE-III optical observations
  18. GRB050215A: ROTSE-III Optical Observations
  19. short/hard GRB 050202, optical observations
  20. GRB 050128: Radio observations
  21. Further analysis of the short Swift-BAT GRB 050202
  22. GRB 050202: Second epoch radio observations
  23. GRB050202: Radio Observations
  24. GRB 050202: Short burst detected by Swift-BAT
  25. SGR1806-20: Swift-BAT detection of a large normal burst
  26. GRB050128: Faulkes Telescope South observations
  27. GRB050128,optical observations
  28. GRB050126: Updated Swift XRT Position
  29. GRB 050126: Radio Observations
  30. GRB050128 Swift-BAT observations
  31. GRB 050128: Swift XRT prompt afterglow position
  32. GRB 050124: K-band afterglow observations
  33. GRB050126: MASTER optical limit for KECK OT
  34. GRB050126: Burst Parameters Measured by BAT
  35. GRB050126: MASTER optical observations
  36. GRB 050126: Prompt XRT detection and localization
  37. GRB050124: No Swift UVOT Detection of Afterglow Emission
  38. GRB 050117a: Radio Observations
  39. GRB050124,optical observation
  40. GRB050124: Updated Swift XRT Position and Fluxes
  41. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  42. GRB050124: Refined BAT position, spectral and fluence information
  43. GRB050124: Swift-BAT position of a double-peaked burst
  44. GRB050117a: Radio Observations
  45. GRB050117a: Refined analysis
  46. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  47. GRB050117b: Swift-BAT detection of a weak burst
  48. GRB050117: optical observation
  49. GRB 050117, I-band observations
  50. GRB 050117: Optical observation
  51. GRB050117: Refined XRT position
  52. GRB050117: MASTER optical observations
  53. MASTER:GRB050117 SWIFT
  54. GRB050117: Swift-BAT detection of a long multi-peaked burst
  55. GRB050117: Swift XRT Position
  56. SGR1806-20: Swift-BAT observations of two additional bursts
  57. SGR 1806-20, RHESSI observations of the 041227 giant flare
  58. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  59. GRB 041217: Optical observations
  60. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  61. GRB041228: ROTSE-III Optical Observations
  62. GRB041228: Swift-BAT detection of a burst
  63. GRB041219; RXTE ASM Observations
  64. NIR Observations of GRB 041219
  65. GRB041226: ROTSE-III Optical Observations
  66. GRB041226: Swift-BAT detection of a burst
  67. GRB041223: decay of the afterglow
  68. GRB041224: ROTSE-III Optical Observations
  69. GRB 041223: XRT afterglow spectrum and light curve
  70. GRB 041223 Fluence measured by Swift-BAT
  71. GRB041224: Swift-BAT detection of a soft burst
  72. GRB041223: optical and NIR observations with REM
  73. Swift-BAT Time History of GRB041219
  74. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  75. GRB041223: ROTSE-III Optical Observations
  76. GRB041223: Swift-BAT detection of a bright long burst
  77. GRB041220: Swift-BAT burst
  78. GRB 041219 Optical Observations
  79. GRB041219c: Third Burst in One Day from Swift-BAT
  80. GRB041219b: A Swift-BAT burst
  81. Swift-BAT detection of the bright long burst GRB041219
  82. GRB041217: optical limit 30 min after GRB
  83. GRB041217: Optical Observations
  84. GRB041217: NIR and optical observations with REM
  85. GRB041217: P60 Optical Observations
  86. GRB041217: Infrared Observations
  87. GRB041217: The First GRB Located On-Board Swift
  88. GRB040916: Optical observations
  89. GRB040422: optical and NIR observations at the VLT
  90. GRB040223, improved XMM position
  91. SN 2003jd (SN/GRB?) - possible association with GRB 030929

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