Skip to main content
End of INTEGRAL Operations. 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').

18186 results found.

  1. GRB 050505: early time observations
  2. GRB 050505 - Faulkes Telescope North observations
  3. GRB 050502a: Swift XRT Upper Limit
  4. GRB 050505, simultaneous optical observation
  5. GRB 050505: Further Swift UVOT observations.
  6. GRB050416A : 1 GHz limit from GMRT
  7. GRB 050505 UVOT
  8. GRB 050505: Swift XRT Position
  9. GRB050505 Swift-BAT refined analysis
  10. GRB 050416b:Swift XRT afterglow upper limits
  11. GRB 050416b:Swift XRT afterglow upper limits
  12. Swift-BAT detection of GRB050505
  13. GRB 050504: Swift XRT position
  14. Swift UVOT observation of GRB 050504
  15. GRB 050502b, V band Observations
  16. GRB050502B Swift-BAT refined analysis
  17. GRB050502B: I band source in XRT error circle
  18. Swift UVOT refined analysis
  19. Retraction of Swift-BAT trigger 116145
  20. GRB 050502b : optical observation at Lulin observatory
  21. GRB 050502b: Swift XRT Position
  22. GRB050502B: Optical Limits from ANU 1m
  23. Swift Detection of the Bright Burst GRB050502b
  24. GRB050502: ANU 1m optical Observations
  25. Swift-BAT Trigger 115881 is not a real GRB
  26. Swift/BAT possible detection of a weak burst GRB050430
  27. GRB 050401: Rc observation
  28. GRB050416a: Radio Detection
  29. GRB 050422: Swift-UVOT observation
  30. GRB 050422: Swift-BAT refined analysis
  31. GRB 050422: Swift XRT Position
  32. Swift Detection of GRB 050422
  33. GRB 050421: SLOTIS observations
  34. GRB050421: Radio Observations
  35. GRB050421: Radio Observations
  36. GRB 050421: Swift-UVOT observation
  37. GRB 050421: Swift-BAT refined analysis
  38. GRB 050421: ROTSE-III Optical Limits
  39. GRB 050421: early Swift XRT analysis results
  40. GRB 050421: BOOTES-2 simultaneous optical observations
  41. GRB 050421: Optical observations at the INT
  42. Swift Detection of GRB050421
  43. GRB 050416b: Tentative Swift XRT Position
  44. GRB050326: analysis of the XMM-Newton observation
  45. GRB 050418: Swift-BAT refined analysis
  46. Swift-BAT detection of the bright and long GRB 050418
  47. GRB 050416B: optical observations
  48. GRB 050416b: Swift-BAT refined analysis
  49. GRB 050416: Swift/UVOT refined analysis
  50. Swift-BAT detection of GRB 050416b
  51. GRB050412: Radio Observations
  52. GRB 050416: Swift/UVOT detection of afterglow emission
  53. GRB050416: Refined Swift-XRT analysis
  54. GRB050416: Maidanak optical observations
  55. GRB 050416: Swift-BAT refined analysis
  56. GRB 050416,optical observation
  57. GRB 050416: KAIT observations
  58. GRB 050416: Swift XRT Position
  59. GRB 050416: Radio observations
  60. Confirmation of OT for GRB050416
  61. GRB050416: P60 Afterglow Candidate
  62. Swift BAT/XRT Detection of GRB 050416
  63. GRB 050412: Subaru observations
  64. GRB 050412: optical limit
  65. GRB 050412: optical observations
  66. GRB 050408: refined XRT analysis, no jet break seen yet
  67. GRB 050412: early Swift XRT analysis results
  68. GRB 050412: Swift-BAT refined analysis
  69. GRB 050412: ANU 2.3m observations
  70. GRB 050412: Early Optical/Ultraviolet Observations with
  71. GRB 050412: retraction of UVOT transient report
  72. GRB 050412: UVOT transient not in XRT error circle
  73. GRB 050412: Swift XRT Position
  74. GRB050412: optical limit before and during GRB
  75. GRB050412: ROTSE-III Optical Limits
  76. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  77. GRB 050412: IR Observations
  78. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  79. GRB 050410, optical observations
  80. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  81. GRB 050410 R band Optical Observations
  82. GRB050410 : Null detection report
  83. GRB 050410, optical observations
  84. GRB050410: Radio Observations
  85. GRB 050408: Swift XRT measurement of possible jet break
  86. GRB050410: MASTER optical observations
  87. GRB 050410: Early observations with Swift-UVOT
  88. Swift-BAT detection of GRB 050410
  89. GRB 050410: Swift XRT Position
  90. GRB 050408: Properties of the Host Galaxy
  91. GRB 050408: Swift XRT analysis
  92. GRB 050408, optical observations
  93. GRB050408: REM NIR and Optical observation
  94. GRB 050408 Optical Observations
  95. GRB 050408: Optical afterglow confirmed
  96. GRB 050408, optical observations
  97. GRB 050408 optical candidate
  98. GRB 050408: Swift XRT Position
  99. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  100. GRB 050406: early Swift XRT analysis results

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