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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"

19593 results found.

  1. GRB 050509b: optical observations
  2. GRB 050509b: Swift XRT Position
  3. GRB 050509B: ROTSE-III Optical Limits
  4. Swift Detection of GRB050509b: A short duration burst
  5. GRB 050509a: Swift XRT Position
  6. Swift Detection of the Burst GRB050509
  7. Swift-BAT detection of GRB 050507
  8. GRB 050505: early time observations
  9. GRB 050505 - Faulkes Telescope North observations
  10. GRB 050502a: Swift XRT Upper Limit
  11. GRB 050505, simultaneous optical observation
  12. GRB 050505: Further Swift UVOT observations.
  13. GRB050416A : 1 GHz limit from GMRT
  14. GRB 050505 UVOT
  15. GRB 050505: Swift XRT Position
  16. GRB050505 Swift-BAT refined analysis
  17. GRB 050416b:Swift XRT afterglow upper limits
  18. GRB 050416b:Swift XRT afterglow upper limits
  19. Swift-BAT detection of GRB050505
  20. GRB 050504: Swift XRT position
  21. Swift UVOT observation of GRB 050504
  22. GRB 050502b, V band Observations
  23. GRB050502B Swift-BAT refined analysis
  24. GRB050502B: I band source in XRT error circle
  25. Swift UVOT refined analysis
  26. Retraction of Swift-BAT trigger 116145
  27. GRB 050502b : optical observation at Lulin observatory
  28. GRB 050502b: Swift XRT Position
  29. GRB050502B: Optical Limits from ANU 1m
  30. Swift Detection of the Bright Burst GRB050502b
  31. GRB050502: ANU 1m optical Observations
  32. Swift-BAT Trigger 115881 is not a real GRB
  33. Swift/BAT possible detection of a weak burst GRB050430
  34. GRB 050401: Rc observation
  35. GRB050416a: Radio Detection
  36. GRB 050422: Swift-UVOT observation
  37. GRB 050422: Swift-BAT refined analysis
  38. GRB 050422: Swift XRT Position
  39. Swift Detection of GRB 050422
  40. GRB 050421: SLOTIS observations
  41. GRB050421: Radio Observations
  42. GRB050421: Radio Observations
  43. GRB 050421: Swift-UVOT observation
  44. GRB 050421: Swift-BAT refined analysis
  45. GRB 050421: ROTSE-III Optical Limits
  46. GRB 050421: early Swift XRT analysis results
  47. GRB 050421: BOOTES-2 simultaneous optical observations
  48. GRB 050421: Optical observations at the INT
  49. Swift Detection of GRB050421
  50. GRB 050416b: Tentative Swift XRT Position
  51. GRB050326: analysis of the XMM-Newton observation
  52. GRB 050418: Swift-BAT refined analysis
  53. Swift-BAT detection of the bright and long GRB 050418
  54. GRB 050416B: optical observations
  55. GRB 050416b: Swift-BAT refined analysis
  56. GRB 050416: Swift/UVOT refined analysis
  57. Swift-BAT detection of GRB 050416b
  58. GRB050412: Radio Observations
  59. GRB 050416: Swift/UVOT detection of afterglow emission
  60. GRB050416: Refined Swift-XRT analysis
  61. GRB050416: Maidanak optical observations
  62. GRB 050416: Swift-BAT refined analysis
  63. GRB 050416,optical observation
  64. GRB 050416: KAIT observations
  65. GRB 050416: Swift XRT Position
  66. GRB 050416: Radio observations
  67. Confirmation of OT for GRB050416
  68. GRB050416: P60 Afterglow Candidate
  69. Swift BAT/XRT Detection of GRB 050416
  70. GRB 050412: Subaru observations
  71. GRB 050412: optical limit
  72. GRB 050412: optical observations
  73. GRB 050408: refined XRT analysis, no jet break seen yet
  74. GRB 050412: early Swift XRT analysis results
  75. GRB 050412: Swift-BAT refined analysis
  76. GRB 050412: ANU 2.3m observations
  77. GRB 050412: Early Optical/Ultraviolet Observations with
  78. GRB 050412: retraction of UVOT transient report
  79. GRB 050412: UVOT transient not in XRT error circle
  80. GRB 050412: Swift XRT Position
  81. GRB050412: optical limit before and during GRB
  82. GRB050412: ROTSE-III Optical Limits
  83. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  84. GRB 050412: IR Observations
  85. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  86. GRB 050410, optical observations
  87. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  88. GRB 050410 R band Optical Observations
  89. GRB050410 : Null detection report
  90. GRB 050410, optical observations
  91. GRB050410: Radio Observations
  92. GRB 050408: Swift XRT measurement of possible jet break
  93. GRB050410: MASTER optical observations
  94. GRB 050410: Early observations with Swift-UVOT
  95. Swift-BAT detection of GRB 050410
  96. GRB 050410: Swift XRT Position
  97. GRB 050408: Properties of the Host Galaxy
  98. GRB 050408: Swift XRT analysis
  99. GRB 050408, optical observations
  100. GRB050408: REM NIR and Optical observation

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