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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"

27774 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. GRB 050502: PAIRITEL IR Observations
  43. GRB 050502: ROTSE-III Detection of Possible Counterpart
  44. Swift-BAT Trigger 115881 is not a real GRB
  45. Swift/BAT possible detection of a weak burst GRB050430
  46. GRB 050401: Rc observation
  47. GRB050416a: Radio Detection
  48. GRB 050422: Swift-UVOT observation
  49. GRB 050422: Swift-BAT refined analysis
  50. GRB 050422: Swift XRT Position
  51. Swift Detection of GRB 050422
  52. GRB 050416: Optical/NIR observations
  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. GRB050421
  60. GRB 050421: early Swift XRT analysis results
  61. GRB 050421: BOOTES-2 simultaneous optical observations
  62. GRB 050421: Optical observations at the INT
  63. Swift Detection of GRB050421
  64. GRB 050416b: Tentative Swift XRT Position
  65. GRB050326: analysis of the XMM-Newton observation
  66. GRB 050418: Swift-BAT refined analysis
  67. Swift-BAT detection of the bright and long GRB 050418
  68. GRB 050416B: optical observations
  69. GRB 050416b: Swift-BAT refined analysis
  70. GRB 050416: Swift/UVOT refined analysis
  71. Swift-BAT detection of GRB 050416b
  72. GRB050412: Radio Observations
  73. GRB 050416: Swift/UVOT detection of afterglow emission
  74. GRB050416: Refined Swift-XRT analysis
  75. GRB050416: Maidanak optical observations
  76. GRB 050416: Swift-BAT refined analysis
  77. GRB 050416,optical observation
  78. GRB 050416: KAIT observations
  79. GRB 050416: Swift XRT Position
  80. GRB 050416: Radio observations
  81. Confirmation of OT for GRB050416
  82. GRB050416: P60 Afterglow Candidate
  83. Swift BAT/XRT Detection of GRB 050416
  84. GRB 050412: Subaru observations
  85. GRB 050412: optical limit
  86. GRB 050412: optical observations
  87. GRB 050408: refined XRT analysis, no jet break seen yet
  88. GRB 050412: early Swift XRT analysis results
  89. GRB 050412: Swift-BAT refined analysis
  90. GRB 050412: ANU 2.3m observations
  91. GRB 050412: Early Optical/Ultraviolet Observations with
  92. GRB 050412: retraction of UVOT transient report
  93. GRB 050412: UVOT transient not in XRT error circle
  94. GRB 050412: Swift XRT Position
  95. GRB050412: optical limit before and during GRB
  96. GRB050412: ROTSE-III Optical Limits
  97. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  98. GRB 050412: IR Observations
  99. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  100. GRB 050410, optical observations

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