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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. GRB050723: XRT distributed coordinates are not related to the burst
  2. GRB 050721: early afterglow light curve
  3. GRB 050721A: Swift-BAT refined analysis
  4. Correction to GCN Circ 3474 on GRB050525A
  5. GRB 050721A: Early Swift XRT analysis results
  6. GRB050721A: optical decay
  7. GRB 050721: optical afterglow confirmed
  8. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  9. GRB 050721a: Optical Observations
  10. GRB050721A: Swift-BAT detection of a weak burst
  11. GRB 050709: Refined Spectral and Temporal Properties
  12. GRB 050717: PROMPT RcIc Observations
  13. GRB050714b: Radio Observation
  14. GRB050712: Radio Observations
  15. GRB 050714a: Refined XRT analysis and afterglow confirmation
  16. GRB050713a: Radio Observation
  17. Swift-BAT trigger 146731 is not a real GRB
  18. GRB 050712, Tautenburg optical afterglow observations
  19. Swift-BAT detection of a possible GRB
  20. GRB 050714B: VLT R-band observations
  21. GRB 050717: Additional LCO observations
  22. GRB050717
  23. GRB 050716; J-band observations
  24. Konus-Wind observation of GRB 050717
  25. GRB 050717: LCO near-IR observations
  26. Swift/UVOT Observations of GRB 050717
  27. GRB 050717: Swift-BAT refined analysis
  28. GRB 050717: Refined XRT analysis.
  29. GRB050712: optical limits
  30. GRB050717: Swift XRT position
  31. Swift detection of GRB 050717
  32. GRB 050716 - UKIRT identification of candidate afterglow
  33. Swift UVOT Observations of GRB 050716
  34. GRB 050716: Refined XRT analysis.
  35. GRB050716: Refined analysis of the Swift-BAT burst
  36. GRB 050716: Lulin B and R band optical observations
  37. GRB050716, optical observation
  38. GRB 050716: Optical Observations
  39. GRB050716: Faulkes North Telescope observation
  40. GRB050716: Correction to sign in XRT coordinate
  41. Swift/BAT detection of GRB 050716
  42. GRB050715: Refined analysis of the Swift-BAT burst
  43. GRB 050715: Swift-BAT detection
  44. Swift UVOT Observations of GRB 050714B
  45. Konus-Wind observation of GRB 050713A
  46. GRB 050714B: refined XRT analysis
  47. GRB 050713b: RTT150 optical observations
  48. GRB 050714B: candidate afterglow does not fade
  49. GRB050714B: Refined analysis of the Swift-BAT burst
  50. GRB 050714B: optical afterglow
  51. Swift detection of a long transient (GRB 050714B?)
  52. GRB 050709: optical afterglow candidate
  53. GRB 050714, R-band candidate
  54. GRB 050714: Swift XRT afterglow position
  55. GRB 050714, optical observations
  56. GRB 050714A: ROTSE-III Optical Limits
  57. GRB 050714 - A long GRB detected with INTEGRAL
  58. GRB 050713A: XRT refined analysis
  59. GRB 050709: Spectroscopy
  60. GRB 050713A: RAPTOR detection of early optical emission
  61. GRB050713B :Swift/UVOT observations
  62. GRB050713b: XRT refined analysis
  63. GRB050712: TNG R-band observations
  64. GRB 050713B: Swift-BAT Refined Analysis
  65. Swift-BAT Trigger 145729 is not a GRB
  66. GRB 050713A: Swift/UVOT observation
  67. GRB 050713A : Swift-BAT Refined Analysis
  68. GRB050712: Swift UVOT Observation of Afterglow Emission
  69. GRB 050713A : Lulin R-band observation
  70. GRB 050713A XMM-Newton observation
  71. GRB 050713b : Lulin R-band observations
  72. GRB050713B: Faulkes North Telescope observation
  73. RBO RI observations of GRB 050713A
  74. GRB 050713B
  75. GRB050709 : Chandra source optical counterpart
  76. GRB050713: Liverpool Telescope prompt observations
  77. GRB 050712, optical observations
  78. GRB 050713 : Planned XMM-Newton observation
  79. GRB050709: Candidate X-ray Afterglow from Chandra
  80. GRB 050713, R-band observations at NOT
  81. GRB 050713: ARC NIR Detections and Identification of Fading
  82. GRB050713: possible I-band afterglow
  83. GRB 050713: Swift detection of Bright Burst
  84. GRB 050713A: ROTSE-III Optical Limits
  85. GRB050712: XRT refined analysis
  86. GRB050709: Radio Observations
  87. GRB 050709: Swift UVOT and XRT observations
  88. GRB 050712: Swift-BAT Refined Analysis
  89. GRB050712: UVOT candidate optical counterpart
  90. GRB 050712: Swift XRT afterglow position
  91. GRB 050712: Swift detection of a weak burst
  92. GRB 050709: LCO40 Observations
  93. GRB050709, optical observations
  94. GRB050709: A Possible Short-Hard GRB Localized by HETE
  95. PROMPT Rc Observations of GRB 050709
  96. GRB 050525a: PROMPT VRcIc Detections
  97. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  98. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  99. GRB 050626 optical observations
  100. GRB 050626: Swift XRT observations

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