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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"

19201 results found.

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

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