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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. GRB 050714a: Refined XRT analysis and afterglow confirmation
  2. GRB050713a: Radio Observation
  3. Swift-BAT trigger 146731 is not a real GRB
  4. GRB 050712, Tautenburg optical afterglow observations
  5. Swift-BAT detection of a possible GRB
  6. GRB 050714B: VLT R-band observations
  7. GRB 050717: Additional LCO observations
  8. GRB050717
  9. GRB 050716; J-band observations
  10. Konus-Wind observation of GRB 050717
  11. GRB 050717: LCO near-IR observations
  12. Swift/UVOT Observations of GRB 050717
  13. GRB 050717: Swift-BAT refined analysis
  14. GRB 050717: Refined XRT analysis.
  15. GRB050712: optical limits
  16. GRB050717: Swift XRT position
  17. Swift detection of GRB 050717
  18. GRB 050716 - UKIRT identification of candidate afterglow
  19. Swift UVOT Observations of GRB 050716
  20. GRB 050716: Refined XRT analysis.
  21. GRB050716: Refined analysis of the Swift-BAT burst
  22. GRB 050716: Lulin B and R band optical observations
  23. GRB050716, optical observation
  24. GRB 050716: Optical Observations
  25. GRB050716: Faulkes North Telescope observation
  26. GRB050716: Correction to sign in XRT coordinate
  27. Swift/BAT detection of GRB 050716
  28. GRB050715: Refined analysis of the Swift-BAT burst
  29. GRB 050715: Swift-BAT detection
  30. Swift UVOT Observations of GRB 050714B
  31. Konus-Wind observation of GRB 050713A
  32. GRB 050714B: refined XRT analysis
  33. GRB 050713b: RTT150 optical observations
  34. GRB 050714B: candidate afterglow does not fade
  35. GRB050714B: Refined analysis of the Swift-BAT burst
  36. GRB 050714B: optical afterglow
  37. Swift detection of a long transient (GRB 050714B?)
  38. GRB 050709: optical afterglow candidate
  39. GRB 050714, R-band candidate
  40. GRB 050714: Swift XRT afterglow position
  41. GRB 050714, optical observations
  42. GRB 050714A: ROTSE-III Optical Limits
  43. GRB 050714 - A long GRB detected with INTEGRAL
  44. GRB 050713A: XRT refined analysis
  45. GRB 050709: Spectroscopy
  46. GRB 050713A: RAPTOR detection of early optical emission
  47. GRB050713B :Swift/UVOT observations
  48. GRB050713b: XRT refined analysis
  49. GRB050712: TNG R-band observations
  50. GRB 050713B: Swift-BAT Refined Analysis
  51. Swift-BAT Trigger 145729 is not a GRB
  52. GRB 050713A: Swift/UVOT observation
  53. GRB 050713A : Swift-BAT Refined Analysis
  54. GRB050712: Swift UVOT Observation of Afterglow Emission
  55. GRB 050713A : Lulin R-band observation
  56. GRB 050713A XMM-Newton observation
  57. GRB 050713b : Lulin R-band observations
  58. GRB050713B: Faulkes North Telescope observation
  59. RBO RI observations of GRB 050713A
  60. GRB 050713B
  61. GRB050709 : Chandra source optical counterpart
  62. GRB050713: Liverpool Telescope prompt observations
  63. GRB 050712, optical observations
  64. GRB 050713 : Planned XMM-Newton observation
  65. GRB050709: Candidate X-ray Afterglow from Chandra
  66. GRB 050713, R-band observations at NOT
  67. GRB 050713: ARC NIR Detections and Identification of Fading
  68. GRB050713: possible I-band afterglow
  69. GRB 050713: Swift detection of Bright Burst
  70. GRB 050713A: ROTSE-III Optical Limits
  71. GRB050712: XRT refined analysis
  72. GRB050709: Radio Observations
  73. GRB 050709: Swift UVOT and XRT observations
  74. GRB 050712: Swift-BAT Refined Analysis
  75. GRB050712: UVOT candidate optical counterpart
  76. GRB 050712: Swift XRT afterglow position
  77. GRB 050712: Swift detection of a weak burst
  78. GRB 050709: LCO40 Observations
  79. GRB050709, optical observations
  80. GRB050709: A Possible Short-Hard GRB Localized by HETE
  81. PROMPT Rc Observations of GRB 050709
  82. GRB 050525a: PROMPT VRcIc Detections
  83. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  84. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  85. GRB 050626 optical observations
  86. GRB 050626: Swift XRT observations
  87. GRB 050701
  88. GRB 050701, optical observations
  89. GRB 050408: ARC 3.5-meter NIR Observations
  90. GRB 050701: Refined XRT analysis
  91. Swift UVOT observations of GRB 050701
  92. GRB050701: Swift-BAT Refined analysis
  93. GRB 050701: Swift XRT afterglow position
  94. Swift trigger 143708 is really GRB 050701
  95. GRB 050607, radio observations
  96. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  97. GRB 050626 - Correction to GCN 3552
  98. GRB 050626 - a long GRB detected with INTEGRAL
  99. GRB 050525A: Swift Late-Time Decay Rate
  100. GRB050525a: HST Observations

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