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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"

19258 results found.

  1. GRB 050422: Swift-UVOT observation
  2. GRB 050422: Swift-BAT refined analysis
  3. GRB 050422: Swift XRT Position
  4. Swift Detection of GRB 050422
  5. GRB 050421: SLOTIS observations
  6. GRB050421: Radio Observations
  7. GRB050421: Radio Observations
  8. GRB 050421: Swift-UVOT observation
  9. GRB 050421: Swift-BAT refined analysis
  10. GRB 050421: ROTSE-III Optical Limits
  11. GRB 050421: early Swift XRT analysis results
  12. GRB 050421: BOOTES-2 simultaneous optical observations
  13. GRB 050421: Optical observations at the INT
  14. Swift Detection of GRB050421
  15. GRB 050416b: Tentative Swift XRT Position
  16. GRB050326: analysis of the XMM-Newton observation
  17. GRB 050418: Swift-BAT refined analysis
  18. Swift-BAT detection of the bright and long GRB 050418
  19. GRB 050416B: optical observations
  20. GRB 050416b: Swift-BAT refined analysis
  21. GRB 050416: Swift/UVOT refined analysis
  22. Swift-BAT detection of GRB 050416b
  23. GRB050412: Radio Observations
  24. GRB 050416: Swift/UVOT detection of afterglow emission
  25. GRB050416: Refined Swift-XRT analysis
  26. GRB050416: Maidanak optical observations
  27. GRB 050416: Swift-BAT refined analysis
  28. GRB 050416,optical observation
  29. GRB 050416: KAIT observations
  30. GRB 050416: Swift XRT Position
  31. GRB 050416: Radio observations
  32. Confirmation of OT for GRB050416
  33. GRB050416: P60 Afterglow Candidate
  34. Swift BAT/XRT Detection of GRB 050416
  35. GRB 050412: Subaru observations
  36. GRB 050412: optical limit
  37. GRB 050412: optical observations
  38. GRB 050408: refined XRT analysis, no jet break seen yet
  39. GRB 050412: early Swift XRT analysis results
  40. GRB 050412: Swift-BAT refined analysis
  41. GRB 050412: ANU 2.3m observations
  42. GRB 050412: Early Optical/Ultraviolet Observations with
  43. GRB 050412: retraction of UVOT transient report
  44. GRB 050412: UVOT transient not in XRT error circle
  45. GRB 050412: Swift XRT Position
  46. GRB050412: optical limit before and during GRB
  47. GRB050412: ROTSE-III Optical Limits
  48. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  49. GRB 050412: IR Observations
  50. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  51. GRB 050410, optical observations
  52. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  53. GRB 050410 R band Optical Observations
  54. GRB050410 : Null detection report
  55. GRB 050410, optical observations
  56. GRB050410: Radio Observations
  57. GRB 050408: Swift XRT measurement of possible jet break
  58. GRB050410: MASTER optical observations
  59. GRB 050410: Early observations with Swift-UVOT
  60. Swift-BAT detection of GRB 050410
  61. GRB 050410: Swift XRT Position
  62. GRB 050408: Properties of the Host Galaxy
  63. GRB 050408: Swift XRT analysis
  64. GRB 050408, optical observations
  65. GRB050408: REM NIR and Optical observation
  66. GRB 050408 Optical Observations
  67. GRB 050408: Optical afterglow confirmed
  68. GRB 050408, optical observations
  69. GRB 050408 optical candidate
  70. GRB 050408: Swift XRT Position
  71. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  72. GRB 050406: early Swift XRT analysis results
  73. GRB 050406 BAT refined analysis
  74. GRB 050406: Early observations with Swift-UVOT
  75. GRB 050406: Swift XRT Position
  76. Swift-BAT detection of GRB 050406
  77. Konus-Wind observation of GRB 050401
  78. GRB050401: Radio observation at 610 MHz with GMRT
  79. GRB 050401: VLT spectroscopic redshift
  80. GRB 050401 Optical Observations
  81. GRB050401: Maidanak optical observation
  82. GRB 050401 BAT refined analysis
  83. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  84. GRB 050402A: IR Observations
  85. GRB 050402: Early observations with Swift-UVOT
  86. Swift Trigger 113225: P60 Observations
  87. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  88. GRB 050401: Optical afterglow candidate
  89. Swift-BAT detection of GRB 050401
  90. GRB 050401: Prompt XRT position
  91. Retraction of three Swift GRB triggers
  92. Swift-BAT detection of GRB 050331b
  93. GRB 050331: Swift UVOT Source
  94. Swift-BAT detection of GRB 050331
  95. GRB 050331: Swift XRT Position
  96. Swift Data Publicly Available Starting April 5, 2005
  97. Konus-Wind observation of GRB 050326
  98. GRB050326: optical limit
  99. GRB 050326: Early observations with Swift-UVOT
  100. GRB 050326 XMM-Newton observation

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