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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"

18506 results found.

  1. GRB050509B: Optical observations at the Very Large Telescope
  2. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  3. GRB 050509a: Swift-BAT refined analysis
  4. GRB 050509B: WSRT Radio Observations
  5. GRB 050505: SARA Observations
  6. Swift UVOT Follow-up Observations of GRB 050509B
  7. GRB 050509B, Optical Observations
  8. GRB 050509B: Swift/XRT refined analysis
  9. GRB050509a: Swift UVOT observations
  10. GRB 050509b: Optical observations
  11. GRB 050509b: Possible Optical Counterpart
  12. GRB 050509A: Optical observations
  13. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  14. GRB 050509b: optical observations
  15. GRB 050509b: Swift XRT Position
  16. GRB 050509B: ROTSE-III Optical Limits
  17. Swift Detection of GRB050509b: A short duration burst
  18. GRB 050509a: Swift XRT Position
  19. Swift Detection of the Burst GRB050509
  20. Swift-BAT detection of GRB 050507
  21. GRB 050505: early time observations
  22. GRB 050505 - Faulkes Telescope North observations
  23. GRB 050502a: Swift XRT Upper Limit
  24. GRB 050505, simultaneous optical observation
  25. GRB 050505: Further Swift UVOT observations.
  26. GRB050416A : 1 GHz limit from GMRT
  27. GRB 050505 UVOT
  28. GRB 050505: Swift XRT Position
  29. GRB050505 Swift-BAT refined analysis
  30. GRB 050416b:Swift XRT afterglow upper limits
  31. GRB 050416b:Swift XRT afterglow upper limits
  32. Swift-BAT detection of GRB050505
  33. GRB 050504: Swift XRT position
  34. Swift UVOT observation of GRB 050504
  35. GRB 050502b, V band Observations
  36. GRB050502B Swift-BAT refined analysis
  37. GRB050502B: I band source in XRT error circle
  38. Swift UVOT refined analysis
  39. Retraction of Swift-BAT trigger 116145
  40. GRB 050502b : optical observation at Lulin observatory
  41. GRB 050502b: Swift XRT Position
  42. GRB050502B: Optical Limits from ANU 1m
  43. Swift Detection of the Bright Burst GRB050502b
  44. GRB050502: ANU 1m optical Observations
  45. Swift-BAT Trigger 115881 is not a real GRB
  46. Swift/BAT possible detection of a weak burst GRB050430
  47. GRB 050401: Rc observation
  48. GRB050416a: Radio Detection
  49. GRB 050422: Swift-UVOT observation
  50. GRB 050422: Swift-BAT refined analysis
  51. GRB 050422: Swift XRT Position
  52. Swift Detection of GRB 050422
  53. GRB 050421: SLOTIS observations
  54. GRB050421: Radio Observations
  55. GRB050421: Radio Observations
  56. GRB 050421: Swift-UVOT observation
  57. GRB 050421: Swift-BAT refined analysis
  58. GRB 050421: ROTSE-III Optical Limits
  59. GRB 050421: early Swift XRT analysis results
  60. GRB 050421: BOOTES-2 simultaneous optical observations
  61. GRB 050421: Optical observations at the INT
  62. Swift Detection of GRB050421
  63. GRB 050416b: Tentative Swift XRT Position
  64. GRB050326: analysis of the XMM-Newton observation
  65. GRB 050418: Swift-BAT refined analysis
  66. Swift-BAT detection of the bright and long GRB 050418
  67. GRB 050416B: optical observations
  68. GRB 050416b: Swift-BAT refined analysis
  69. GRB 050416: Swift/UVOT refined analysis
  70. Swift-BAT detection of GRB 050416b
  71. GRB050412: Radio Observations
  72. GRB 050416: Swift/UVOT detection of afterglow emission
  73. GRB050416: Refined Swift-XRT analysis
  74. GRB050416: Maidanak optical observations
  75. GRB 050416: Swift-BAT refined analysis
  76. GRB 050416,optical observation
  77. GRB 050416: KAIT observations
  78. GRB 050416: Swift XRT Position
  79. GRB 050416: Radio observations
  80. Confirmation of OT for GRB050416
  81. GRB050416: P60 Afterglow Candidate
  82. Swift BAT/XRT Detection of GRB 050416
  83. GRB 050412: Subaru observations
  84. GRB 050412: optical limit
  85. GRB 050412: optical observations
  86. GRB 050408: refined XRT analysis, no jet break seen yet
  87. GRB 050412: early Swift XRT analysis results
  88. GRB 050412: Swift-BAT refined analysis
  89. GRB 050412: ANU 2.3m observations
  90. GRB 050412: Early Optical/Ultraviolet Observations with
  91. GRB 050412: retraction of UVOT transient report
  92. GRB 050412: UVOT transient not in XRT error circle
  93. GRB 050412: Swift XRT Position
  94. GRB050412: optical limit before and during GRB
  95. GRB050412: ROTSE-III Optical Limits
  96. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  97. GRB 050412: IR Observations
  98. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  99. GRB 050410, optical observations
  100. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT

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