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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"

18602 results found.

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

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