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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"

19941 results found.

  1. GRB 050504: Swift XRT afterglow candidate has faded
  2. GRB 050509B: Subaru Optical Observations
  3. GRB050502b: Early Observation
  4. Refined Chandra analysis of GRB 050509b
  5. GRB050509b, SDSS pre-burst observations
  6. Chandra observation of GRB 050509b
  7. GRB 050509b: RAPTOR deep, early limits.
  8. GRB050509B: Optical/Infared observations
  9. GRB 050509b: Swift/UVOT follow-up measurements
  10. GRB 050509b Milagro GeV/TeV Observations
  11. GRB050509B: Optical observations at the Very Large Telescope
  12. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  13. GRB 050509a: Swift-BAT refined analysis
  14. GRB 050509B: WSRT Radio Observations
  15. GRB 050505: SARA Observations
  16. Swift UVOT Follow-up Observations of GRB 050509B
  17. GRB 050509B, Optical Observations
  18. GRB 050509B: Swift/XRT refined analysis
  19. GRB050509a: Swift UVOT observations
  20. GRB 050509b: Optical observations
  21. GRB 050509b: Possible Optical Counterpart
  22. GRB 050509A: Optical observations
  23. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  24. GRB 050509b: optical observations
  25. GRB 050509b: Swift XRT Position
  26. GRB 050509B: ROTSE-III Optical Limits
  27. Swift Detection of GRB050509b: A short duration burst
  28. GRB 050509a: Swift XRT Position
  29. Swift Detection of the Burst GRB050509
  30. Swift-BAT detection of GRB 050507
  31. GRB 050505: early time observations
  32. GRB 050505 - Faulkes Telescope North observations
  33. GRB 050502a: Swift XRT Upper Limit
  34. GRB 050505, simultaneous optical observation
  35. GRB 050505: Further Swift UVOT observations.
  36. GRB050416A : 1 GHz limit from GMRT
  37. GRB 050505 UVOT
  38. GRB 050505: Swift XRT Position
  39. GRB050505 Swift-BAT refined analysis
  40. GRB 050416b:Swift XRT afterglow upper limits
  41. GRB 050416b:Swift XRT afterglow upper limits
  42. Swift-BAT detection of GRB050505
  43. GRB 050504: Swift XRT position
  44. Swift UVOT observation of GRB 050504
  45. GRB 050502b, V band Observations
  46. Renewal of SGR 1806-20 activity
  47. GRB050502B Swift-BAT refined analysis
  48. GRB050502B: I band source in XRT error circle
  49. Swift UVOT refined analysis
  50. Retraction of Swift-BAT trigger 116145
  51. GRB 050502b : optical observation at Lulin observatory
  52. GRB 050502b: Swift XRT Position
  53. GRB050502B: Optical Limits from ANU 1m
  54. Swift Detection of the Bright Burst GRB050502b
  55. GRB050502: ANU 1m optical Observations
  56. Swift-BAT Trigger 115881 is not a real GRB
  57. Swift/BAT possible detection of a weak burst GRB050430
  58. GRB 050401: Rc observation
  59. GRB050416a: Radio Detection
  60. GRB 050422: Swift-UVOT observation
  61. GRB 050422: Swift-BAT refined analysis
  62. GRB 050422: Swift XRT Position
  63. Swift Detection of GRB 050422
  64. GRB 050421: SLOTIS observations
  65. GRB050421: Radio Observations
  66. GRB050421: Radio Observations
  67. GRB 050421: Swift-UVOT observation
  68. GRB 050421: Swift-BAT refined analysis
  69. GRB 050421: ROTSE-III Optical Limits
  70. GRB 050421: early Swift XRT analysis results
  71. GRB 050421: BOOTES-2 simultaneous optical observations
  72. GRB 050421: Optical observations at the INT
  73. Swift Detection of GRB050421
  74. GRB 050416b: Tentative Swift XRT Position
  75. GRB050326: analysis of the XMM-Newton observation
  76. GRB 050418: Swift-BAT refined analysis
  77. Swift-BAT detection of the bright and long GRB 050418
  78. GRB 050416B: optical observations
  79. GRB 050416b: Swift-BAT refined analysis
  80. GRB 050416: Swift/UVOT refined analysis
  81. Swift-BAT detection of GRB 050416b
  82. GRB050412: Radio Observations
  83. GRB 050416: Swift/UVOT detection of afterglow emission
  84. GRB050416: Refined Swift-XRT analysis
  85. GRB050416: Maidanak optical observations
  86. GRB 050416: Swift-BAT refined analysis
  87. GRB 050416,optical observation
  88. GRB 050416: KAIT observations
  89. GRB 050416: Swift XRT Position
  90. GRB 050416: Radio observations
  91. Confirmation of OT for GRB050416
  92. GRB050416: P60 Afterglow Candidate
  93. Swift BAT/XRT Detection of GRB 050416
  94. GRB 050412: Subaru observations
  95. GRB 050412: optical limit
  96. GRB 050412: optical observations
  97. GRB 050408: refined XRT analysis, no jet break seen yet
  98. GRB 050412: early Swift XRT analysis results
  99. GRB 050412: Swift-BAT refined analysis
  100. GRB 050412: ANU 2.3m observations

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