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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 050712, Tautenburg optical afterglow observations
  2. Swift-BAT detection of a possible GRB
  3. GRB 050714B: VLT R-band observations
  4. GRB 050717: Additional LCO observations
  5. GRB050717
  6. GRB 050716; J-band observations
  7. Konus-Wind observation of GRB 050717
  8. GRB 050717: LCO near-IR observations
  9. Swift/UVOT Observations of GRB 050717
  10. GRB 050717: Swift-BAT refined analysis
  11. GRB 050717: Refined XRT analysis.
  12. GRB050712: optical limits
  13. GRB050717: Swift XRT position
  14. Swift detection of GRB 050717
  15. GRB 050716 - UKIRT identification of candidate afterglow
  16. Swift UVOT Observations of GRB 050716
  17. GRB 050716: Refined XRT analysis.
  18. GRB050716: Refined analysis of the Swift-BAT burst
  19. GRB 050716: Lulin B and R band optical observations
  20. GRB050716, optical observation
  21. GRB 050716: Optical Observations
  22. GRB050716: Faulkes North Telescope observation
  23. GRB050716: Correction to sign in XRT coordinate
  24. Swift/BAT detection of GRB 050716
  25. GRB050715: Refined analysis of the Swift-BAT burst
  26. GRB 050715: Swift-BAT detection
  27. Swift UVOT Observations of GRB 050714B
  28. Konus-Wind observation of GRB 050713A
  29. GRB 050714B: refined XRT analysis
  30. GRB 050713b: RTT150 optical observations
  31. GRB 050714B: candidate afterglow does not fade
  32. GRB050714B: Refined analysis of the Swift-BAT burst
  33. GRB 050714B: optical afterglow
  34. Swift detection of a long transient (GRB 050714B?)
  35. GRB 050709: optical afterglow candidate
  36. GRB 050714, R-band candidate
  37. GRB 050714: Swift XRT afterglow position
  38. GRB 050714, optical observations
  39. GRB 050714A: ROTSE-III Optical Limits
  40. GRB 050714 - A long GRB detected with INTEGRAL
  41. GRB 050713A: XRT refined analysis
  42. GRB 050709: Spectroscopy
  43. GRB 050713A: RAPTOR detection of early optical emission
  44. GRB050713B :Swift/UVOT observations
  45. GRB050713b: XRT refined analysis
  46. GRB050712: TNG R-band observations
  47. GRB 050713B: Swift-BAT Refined Analysis
  48. Swift-BAT Trigger 145729 is not a GRB
  49. GRB 050713A: Swift/UVOT observation
  50. GRB 050713A : Swift-BAT Refined Analysis
  51. GRB050712: Swift UVOT Observation of Afterglow Emission
  52. GRB 050713A : Lulin R-band observation
  53. GRB 050713A XMM-Newton observation
  54. GRB 050713b : Lulin R-band observations
  55. GRB050713B: Faulkes North Telescope observation
  56. RBO RI observations of GRB 050713A
  57. GRB 050713B
  58. GRB050709 : Chandra source optical counterpart
  59. GRB050713: Liverpool Telescope prompt observations
  60. GRB 050712, optical observations
  61. GRB 050713 : Planned XMM-Newton observation
  62. GRB050709: Candidate X-ray Afterglow from Chandra
  63. GRB 050713, R-band observations at NOT
  64. GRB 050713: ARC NIR Detections and Identification of Fading
  65. GRB050713: possible I-band afterglow
  66. GRB 050713: Swift detection of Bright Burst
  67. GRB 050713A: ROTSE-III Optical Limits
  68. GRB050712: XRT refined analysis
  69. GRB050709: Radio Observations
  70. GRB 050709: Swift UVOT and XRT observations
  71. GRB 050712: Swift-BAT Refined Analysis
  72. GRB050712: UVOT candidate optical counterpart
  73. GRB 050712: Swift XRT afterglow position
  74. GRB 050712: Swift detection of a weak burst
  75. GRB 050709: LCO40 Observations
  76. GRB050709, optical observations
  77. GRB050709: A Possible Short-Hard GRB Localized by HETE
  78. PROMPT Rc Observations of GRB 050709
  79. GRB 050525a: PROMPT VRcIc Detections
  80. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  81. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  82. GRB 050626 optical observations
  83. GRB 050626: Swift XRT observations
  84. GRB 050701
  85. GRB 050701, optical observations
  86. GRB 050408: ARC 3.5-meter NIR Observations
  87. GRB 050701: Refined XRT analysis
  88. Swift UVOT observations of GRB 050701
  89. GRB050701: Swift-BAT Refined analysis
  90. GRB 050701: Swift XRT afterglow position
  91. Swift trigger 143708 is really GRB 050701
  92. GRB 050607, radio observations
  93. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  94. GRB 050626 - Correction to GCN 3552
  95. GRB 050626 - a long GRB detected with INTEGRAL
  96. GRB 050525A: Swift Late-Time Decay Rate
  97. GRB050525a: HST Observations
  98. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  99. H3804: A Possible New XRB Detected by HETE
  100. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE

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