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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"
  1. GRB050721A: Swift-BAT detection of a weak burst
  2. GRB 050709: Refined Spectral and Temporal Properties
  3. GRB 050717: PROMPT RcIc Observations
  4. GRB050714b: Radio Observation
  5. GRB050712: Radio Observations
  6. GRB 050714a: Refined XRT analysis and afterglow confirmation
  7. GRB050713a: Radio Observation
  8. Swift-BAT trigger 146731 is not a real GRB
  9. GRB 050712, Tautenburg optical afterglow observations
  10. Swift-BAT detection of a possible GRB
  11. GRB 050714B: VLT R-band observations
  12. GRB 050717: Additional LCO observations
  13. GRB050717
  14. GRB 050716; J-band observations
  15. Konus-Wind observation of GRB 050717
  16. GRB 050717: LCO near-IR observations
  17. Swift/UVOT Observations of GRB 050717
  18. GRB 050717: Swift-BAT refined analysis
  19. GRB 050717: Refined XRT analysis.
  20. GRB050712: optical limits
  21. GRB050717: Swift XRT position
  22. Swift detection of GRB 050717
  23. GRB 050716 - UKIRT identification of candidate afterglow
  24. Swift UVOT Observations of GRB 050716
  25. GRB 050716: Refined XRT analysis.
  26. GRB050716: Refined analysis of the Swift-BAT burst
  27. GRB 050716: Lulin B and R band optical observations
  28. GRB050716, optical observation
  29. GRB 050716: Optical Observations
  30. GRB050716: Faulkes North Telescope observation
  31. GRB050716: Correction to sign in XRT coordinate
  32. Swift/BAT detection of GRB 050716
  33. GRB050715: Refined analysis of the Swift-BAT burst
  34. GRB 050715: Swift-BAT detection
  35. Swift UVOT Observations of GRB 050714B
  36. Konus-Wind observation of GRB 050713A
  37. GRB 050714B: refined XRT analysis
  38. GRB 050713b: RTT150 optical observations
  39. GRB 050714B: candidate afterglow does not fade
  40. GRB050714B: Refined analysis of the Swift-BAT burst
  41. GRB 050714B: optical afterglow
  42. Swift detection of a long transient (GRB 050714B?)
  43. GRB 050709: optical afterglow candidate
  44. GRB 050714, R-band candidate
  45. GRB 050714: Swift XRT afterglow position
  46. GRB 050714, optical observations
  47. GRB 050714A: ROTSE-III Optical Limits
  48. GRB 050714 - A long GRB detected with INTEGRAL
  49. GRB 050713A: XRT refined analysis
  50. GRB 050709: Spectroscopy
  51. GRB 050713A: RAPTOR detection of early optical emission
  52. GRB050713B :Swift/UVOT observations
  53. GRB050713b: XRT refined analysis
  54. GRB050712: TNG R-band observations
  55. GRB 050713B: Swift-BAT Refined Analysis
  56. Swift-BAT Trigger 145729 is not a GRB
  57. GRB 050713A: Swift/UVOT observation
  58. GRB 050713A : Swift-BAT Refined Analysis
  59. GRB050712: Swift UVOT Observation of Afterglow Emission
  60. GRB 050713A : Lulin R-band observation
  61. GRB 050713A XMM-Newton observation
  62. GRB 050713b : Lulin R-band observations
  63. GRB050713B: Faulkes North Telescope observation
  64. RBO RI observations of GRB 050713A
  65. GRB 050713B
  66. GRB050709 : Chandra source optical counterpart
  67. GRB050713: Liverpool Telescope prompt observations
  68. GRB 050712, optical observations
  69. GRB 050713 : Planned XMM-Newton observation
  70. GRB050709: Candidate X-ray Afterglow from Chandra
  71. GRB 050713, R-band observations at NOT
  72. GRB 050713: ARC NIR Detections and Identification of Fading
  73. GRB050713: possible I-band afterglow
  74. GRB 050713: Swift detection of Bright Burst
  75. GRB 050713A: ROTSE-III Optical Limits
  76. GRB050712: XRT refined analysis
  77. GRB050709: Radio Observations
  78. GRB 050709: Swift UVOT and XRT observations
  79. GRB 050712: Swift-BAT Refined Analysis
  80. GRB050712: UVOT candidate optical counterpart
  81. GRB 050712: Swift XRT afterglow position
  82. GRB 050712: Swift detection of a weak burst
  83. GRB 050709: LCO40 Observations
  84. GRB050709, optical observations
  85. GRB050709: A Possible Short-Hard GRB Localized by HETE
  86. PROMPT Rc Observations of GRB 050709
  87. GRB 050525a: PROMPT VRcIc Detections
  88. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  89. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  90. GRB 050626 optical observations
  91. GRB 050626: Swift XRT observations
  92. GRB 050701
  93. GRB 050701, optical observations
  94. GRB 050408: ARC 3.5-meter NIR Observations
  95. GRB 050701: Refined XRT analysis
  96. Swift UVOT observations of GRB 050701
  97. GRB050701: Swift-BAT Refined analysis
  98. GRB 050701: Swift XRT afterglow position
  99. Swift trigger 143708 is really GRB 050701
  100. GRB 050607, radio observations

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