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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"

18651 results found.

  1. GRB 050421: Swift-UVOT observation
  2. GRB 050421: Swift-BAT refined analysis
  3. GRB 050421: ROTSE-III Optical Limits
  4. GRB 050421: early Swift XRT analysis results
  5. GRB 050421: BOOTES-2 simultaneous optical observations
  6. GRB 050421: Optical observations at the INT
  7. Swift Detection of GRB050421
  8. GRB 050416b: Tentative Swift XRT Position
  9. GRB050326: analysis of the XMM-Newton observation
  10. GRB 050418: Swift-BAT refined analysis
  11. Swift-BAT detection of the bright and long GRB 050418
  12. GRB 050416B: optical observations
  13. GRB 050416b: Swift-BAT refined analysis
  14. GRB 050416: Swift/UVOT refined analysis
  15. Swift-BAT detection of GRB 050416b
  16. GRB050412: Radio Observations
  17. GRB 050416: Swift/UVOT detection of afterglow emission
  18. GRB050416: Refined Swift-XRT analysis
  19. GRB050416: Maidanak optical observations
  20. GRB 050416: Swift-BAT refined analysis
  21. GRB 050416,optical observation
  22. GRB 050416: KAIT observations
  23. GRB 050416: Swift XRT Position
  24. GRB 050416: Radio observations
  25. Confirmation of OT for GRB050416
  26. GRB050416: P60 Afterglow Candidate
  27. Swift BAT/XRT Detection of GRB 050416
  28. GRB 050412: Subaru observations
  29. GRB 050412: optical limit
  30. GRB 050412: optical observations
  31. GRB 050408: refined XRT analysis, no jet break seen yet
  32. GRB 050412: early Swift XRT analysis results
  33. GRB 050412: Swift-BAT refined analysis
  34. GRB 050412: ANU 2.3m observations
  35. GRB 050412: Early Optical/Ultraviolet Observations with
  36. GRB 050412: retraction of UVOT transient report
  37. GRB 050412: UVOT transient not in XRT error circle
  38. GRB 050412: Swift XRT Position
  39. GRB050412: optical limit before and during GRB
  40. GRB050412: ROTSE-III Optical Limits
  41. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  42. GRB 050412: IR Observations
  43. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  44. GRB 050410, optical observations
  45. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  46. GRB 050410 R band Optical Observations
  47. GRB050410 : Null detection report
  48. GRB 050410, optical observations
  49. GRB050410: Radio Observations
  50. GRB 050408: Swift XRT measurement of possible jet break
  51. GRB050410: MASTER optical observations
  52. GRB 050410: Early observations with Swift-UVOT
  53. Swift-BAT detection of GRB 050410
  54. GRB 050410: Swift XRT Position
  55. GRB 050408: Properties of the Host Galaxy
  56. GRB 050408: Swift XRT analysis
  57. GRB 050408, optical observations
  58. GRB050408: REM NIR and Optical observation
  59. GRB 050408 Optical Observations
  60. GRB 050408: Optical afterglow confirmed
  61. GRB 050408, optical observations
  62. GRB 050408 optical candidate
  63. GRB 050408: Swift XRT Position
  64. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  65. GRB 050406: early Swift XRT analysis results
  66. GRB 050406 BAT refined analysis
  67. GRB 050406: Early observations with Swift-UVOT
  68. GRB 050406: Swift XRT Position
  69. Swift-BAT detection of GRB 050406
  70. Konus-Wind observation of GRB 050401
  71. GRB050401: Radio observation at 610 MHz with GMRT
  72. GRB 050401: VLT spectroscopic redshift
  73. GRB 050401 Optical Observations
  74. GRB050401: Maidanak optical observation
  75. GRB 050401 BAT refined analysis
  76. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  77. GRB 050402A: IR Observations
  78. GRB 050402: Early observations with Swift-UVOT
  79. Swift Trigger 113225: P60 Observations
  80. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  81. GRB 050401: Optical afterglow candidate
  82. Swift-BAT detection of GRB 050401
  83. GRB 050401: Prompt XRT position
  84. Retraction of three Swift GRB triggers
  85. Swift-BAT detection of GRB 050331b
  86. GRB 050331: Swift UVOT Source
  87. Swift-BAT detection of GRB 050331
  88. GRB 050331: Swift XRT Position
  89. Swift Data Publicly Available Starting April 5, 2005
  90. Konus-Wind observation of GRB 050326
  91. GRB050326: optical limit
  92. GRB 050326: Early observations with Swift-UVOT
  93. GRB 050326 XMM-Newton observation
  94. GRB 050326 : Planned XMM-Newton observation
  95. GRB 050326: Swift XRT Position
  96. GRB050326: optical limit 33min before GRB
  97. GRB 050326 BAT refined analysis
  98. GRB050326: delayed XRT observation
  99. Swift-BAT detection of a bright GRB 050326
  100. GRB050319, optical observations

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