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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"

18400 results found.

  1. GRB 050509B, Optical Observations
  2. GRB 050509B: Swift/XRT refined analysis
  3. GRB050509a: Swift UVOT observations
  4. GRB 050509b: Optical observations
  5. GRB 050509b: Possible Optical Counterpart
  6. GRB 050509A: Optical observations
  7. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  8. GRB 050509b: optical observations
  9. GRB 050509b: Swift XRT Position
  10. GRB 050509B: ROTSE-III Optical Limits
  11. Swift Detection of GRB050509b: A short duration burst
  12. GRB 050509a: Swift XRT Position
  13. Swift Detection of the Burst GRB050509
  14. Swift-BAT detection of GRB 050507
  15. GRB 050505: early time observations
  16. GRB 050505 - Faulkes Telescope North observations
  17. GRB 050502a: Swift XRT Upper Limit
  18. GRB 050505, simultaneous optical observation
  19. GRB 050505: Further Swift UVOT observations.
  20. GRB050416A : 1 GHz limit from GMRT
  21. GRB 050505 UVOT
  22. GRB 050505: Swift XRT Position
  23. GRB050505 Swift-BAT refined analysis
  24. GRB 050416b:Swift XRT afterglow upper limits
  25. GRB 050416b:Swift XRT afterglow upper limits
  26. Swift-BAT detection of GRB050505
  27. GRB 050504: Swift XRT position
  28. Swift UVOT observation of GRB 050504
  29. GRB 050502b, V band Observations
  30. GRB050502B Swift-BAT refined analysis
  31. GRB050502B: I band source in XRT error circle
  32. Swift UVOT refined analysis
  33. Retraction of Swift-BAT trigger 116145
  34. GRB 050502b : optical observation at Lulin observatory
  35. GRB 050502b: Swift XRT Position
  36. GRB050502B: Optical Limits from ANU 1m
  37. Swift Detection of the Bright Burst GRB050502b
  38. GRB050502: ANU 1m optical Observations
  39. Swift-BAT Trigger 115881 is not a real GRB
  40. Swift/BAT possible detection of a weak burst GRB050430
  41. GRB 050401: Rc observation
  42. GRB050416a: Radio Detection
  43. GRB 050422: Swift-UVOT observation
  44. GRB 050422: Swift-BAT refined analysis
  45. GRB 050422: Swift XRT Position
  46. Swift Detection of GRB 050422
  47. GRB 050421: SLOTIS observations
  48. GRB050421: Radio Observations
  49. GRB050421: Radio Observations
  50. GRB 050421: Swift-UVOT observation
  51. GRB 050421: Swift-BAT refined analysis
  52. GRB 050421: ROTSE-III Optical Limits
  53. GRB 050421: early Swift XRT analysis results
  54. GRB 050421: BOOTES-2 simultaneous optical observations
  55. GRB 050421: Optical observations at the INT
  56. Swift Detection of GRB050421
  57. GRB 050416b: Tentative Swift XRT Position
  58. GRB050326: analysis of the XMM-Newton observation
  59. GRB 050418: Swift-BAT refined analysis
  60. Swift-BAT detection of the bright and long GRB 050418
  61. GRB 050416B: optical observations
  62. GRB 050416b: Swift-BAT refined analysis
  63. GRB 050416: Swift/UVOT refined analysis
  64. Swift-BAT detection of GRB 050416b
  65. GRB050412: Radio Observations
  66. GRB 050416: Swift/UVOT detection of afterglow emission
  67. GRB050416: Refined Swift-XRT analysis
  68. GRB050416: Maidanak optical observations
  69. GRB 050416: Swift-BAT refined analysis
  70. GRB 050416,optical observation
  71. GRB 050416: KAIT observations
  72. GRB 050416: Swift XRT Position
  73. GRB 050416: Radio observations
  74. Confirmation of OT for GRB050416
  75. GRB050416: P60 Afterglow Candidate
  76. Swift BAT/XRT Detection of GRB 050416
  77. GRB 050412: Subaru observations
  78. GRB 050412: optical limit
  79. GRB 050412: optical observations
  80. GRB 050408: refined XRT analysis, no jet break seen yet
  81. GRB 050412: early Swift XRT analysis results
  82. GRB 050412: Swift-BAT refined analysis
  83. GRB 050412: ANU 2.3m observations
  84. GRB 050412: Early Optical/Ultraviolet Observations with
  85. GRB 050412: retraction of UVOT transient report
  86. GRB 050412: UVOT transient not in XRT error circle
  87. GRB 050412: Swift XRT Position
  88. GRB050412: optical limit before and during GRB
  89. GRB050412: ROTSE-III Optical Limits
  90. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  91. GRB 050412: IR Observations
  92. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  93. GRB 050410, optical observations
  94. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  95. GRB 050410 R band Optical Observations
  96. GRB050410 : Null detection report
  97. GRB 050410, optical observations
  98. GRB050410: Radio Observations
  99. GRB 050408: Swift XRT measurement of possible jet break
  100. GRB050410: MASTER optical observations

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