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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"

19603 results found.

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

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