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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"

18745 results found.

  1. Swift Detection of GRB050421
  2. GRB 050416b: Tentative Swift XRT Position
  3. GRB050326: analysis of the XMM-Newton observation
  4. GRB 050418: Swift-BAT refined analysis
  5. Swift-BAT detection of the bright and long GRB 050418
  6. GRB 050416B: optical observations
  7. GRB 050416b: Swift-BAT refined analysis
  8. GRB 050416: Swift/UVOT refined analysis
  9. Swift-BAT detection of GRB 050416b
  10. GRB050412: Radio Observations
  11. GRB 050416: Swift/UVOT detection of afterglow emission
  12. GRB050416: Refined Swift-XRT analysis
  13. GRB050416: Maidanak optical observations
  14. GRB 050416: Swift-BAT refined analysis
  15. GRB 050416,optical observation
  16. GRB 050416: KAIT observations
  17. GRB 050416: Swift XRT Position
  18. GRB 050416: Radio observations
  19. Confirmation of OT for GRB050416
  20. GRB050416: P60 Afterglow Candidate
  21. Swift BAT/XRT Detection of GRB 050416
  22. GRB 050412: Subaru observations
  23. GRB 050412: optical limit
  24. GRB 050412: optical observations
  25. GRB 050408: refined XRT analysis, no jet break seen yet
  26. GRB 050412: early Swift XRT analysis results
  27. GRB 050412: Swift-BAT refined analysis
  28. GRB 050412: ANU 2.3m observations
  29. GRB 050412: Early Optical/Ultraviolet Observations with
  30. GRB 050412: retraction of UVOT transient report
  31. GRB 050412: UVOT transient not in XRT error circle
  32. GRB 050412: Swift XRT Position
  33. GRB050412: optical limit before and during GRB
  34. GRB050412: ROTSE-III Optical Limits
  35. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  36. GRB 050412: IR Observations
  37. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  38. GRB 050410, optical observations
  39. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  40. GRB 050410 R band Optical Observations
  41. GRB050410 : Null detection report
  42. GRB 050410, optical observations
  43. GRB050410: Radio Observations
  44. GRB 050408: Swift XRT measurement of possible jet break
  45. GRB050410: MASTER optical observations
  46. GRB 050410: Early observations with Swift-UVOT
  47. Swift-BAT detection of GRB 050410
  48. GRB 050410: Swift XRT Position
  49. GRB 050408: Properties of the Host Galaxy
  50. GRB 050408: Swift XRT analysis
  51. GRB 050408, optical observations
  52. GRB050408: REM NIR and Optical observation
  53. GRB 050408 Optical Observations
  54. GRB 050408: Optical afterglow confirmed
  55. GRB 050408, optical observations
  56. GRB 050408 optical candidate
  57. GRB 050408: Swift XRT Position
  58. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  59. GRB 050406: early Swift XRT analysis results
  60. GRB 050406 BAT refined analysis
  61. GRB 050406: Early observations with Swift-UVOT
  62. GRB 050406: Swift XRT Position
  63. Swift-BAT detection of GRB 050406
  64. Konus-Wind observation of GRB 050401
  65. GRB050401: Radio observation at 610 MHz with GMRT
  66. GRB 050401: VLT spectroscopic redshift
  67. GRB 050401 Optical Observations
  68. GRB050401: Maidanak optical observation
  69. GRB 050401 BAT refined analysis
  70. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  71. GRB 050402A: IR Observations
  72. GRB 050402: Early observations with Swift-UVOT
  73. Swift Trigger 113225: P60 Observations
  74. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  75. GRB 050401: Optical afterglow candidate
  76. Swift-BAT detection of GRB 050401
  77. GRB 050401: Prompt XRT position
  78. Retraction of three Swift GRB triggers
  79. Swift-BAT detection of GRB 050331b
  80. GRB 050331: Swift UVOT Source
  81. Swift-BAT detection of GRB 050331
  82. GRB 050331: Swift XRT Position
  83. Swift Data Publicly Available Starting April 5, 2005
  84. Konus-Wind observation of GRB 050326
  85. GRB050326: optical limit
  86. GRB 050326: Early observations with Swift-UVOT
  87. GRB 050326 XMM-Newton observation
  88. GRB 050326 : Planned XMM-Newton observation
  89. GRB 050326: Swift XRT Position
  90. GRB050326: optical limit 33min before GRB
  91. GRB 050326 BAT refined analysis
  92. GRB050326: delayed XRT observation
  93. Swift-BAT detection of a bright GRB 050326
  94. GRB050319, optical observations
  95. GRB050319, color indices
  96. GRB050319: RTT150 Optical Observations
  97. Swift-BAT detection of a bright outburst from SGR1806-20
  98. Swift-BAT trigger 112060 is not a real GRB
  99. GRB 050319: ROTSE-III Refined Analysis
  100. GRB 050318: Swift-BAT refined analysis

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