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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').
  1. GRB 050714B: VLT R-band observations
  2. GRB 050717: Additional LCO observations
  3. GRB050717
  4. GRB 050716; J-band observations
  5. Konus-Wind observation of GRB 050717
  6. GRB 050717: LCO near-IR observations
  7. Swift/UVOT Observations of GRB 050717
  8. GRB 050717: Swift-BAT refined analysis
  9. GRB 050717: Refined XRT analysis.
  10. GRB050712: optical limits
  11. GRB050717: Swift XRT position
  12. Swift detection of GRB 050717
  13. GRB 050716 - UKIRT identification of candidate afterglow
  14. Swift UVOT Observations of GRB 050716
  15. GRB 050716: Refined XRT analysis.
  16. GRB050716: Refined analysis of the Swift-BAT burst
  17. GRB 050716: Lulin B and R band optical observations
  18. GRB050716, optical observation
  19. GRB 050716: Optical Observations
  20. GRB050716: Faulkes North Telescope observation
  21. GRB050716: Correction to sign in XRT coordinate
  22. Swift/BAT detection of GRB 050716
  23. GRB050715: Refined analysis of the Swift-BAT burst
  24. GRB 050715: Swift-BAT detection
  25. Swift UVOT Observations of GRB 050714B
  26. Konus-Wind observation of GRB 050713A
  27. GRB 050714B: refined XRT analysis
  28. GRB 050713b: RTT150 optical observations
  29. GRB 050714B: candidate afterglow does not fade
  30. GRB050714B: Refined analysis of the Swift-BAT burst
  31. GRB 050714B: optical afterglow
  32. Swift detection of a long transient (GRB 050714B?)
  33. GRB 050709: optical afterglow candidate
  34. GRB 050714, R-band candidate
  35. GRB 050714: Swift XRT afterglow position
  36. GRB 050714, optical observations
  37. GRB 050714A: ROTSE-III Optical Limits
  38. GRB 050714 - A long GRB detected with INTEGRAL
  39. GRB 050713A: XRT refined analysis
  40. GRB 050709: Spectroscopy
  41. GRB 050713A: RAPTOR detection of early optical emission
  42. GRB050713B :Swift/UVOT observations
  43. GRB050713b: XRT refined analysis
  44. GRB050712: TNG R-band observations
  45. GRB 050713B: Swift-BAT Refined Analysis
  46. Swift-BAT Trigger 145729 is not a GRB
  47. GRB 050713A: Swift/UVOT observation
  48. GRB 050713A : Swift-BAT Refined Analysis
  49. GRB050712: Swift UVOT Observation of Afterglow Emission
  50. GRB 050713A : Lulin R-band observation
  51. GRB 050713A XMM-Newton observation
  52. GRB 050713b : Lulin R-band observations
  53. GRB050713B: Faulkes North Telescope observation
  54. RBO RI observations of GRB 050713A
  55. GRB 050713B
  56. GRB050709 : Chandra source optical counterpart
  57. GRB050713: Liverpool Telescope prompt observations
  58. GRB 050712, optical observations
  59. GRB 050713 : Planned XMM-Newton observation
  60. GRB050709: Candidate X-ray Afterglow from Chandra
  61. GRB 050713, R-band observations at NOT
  62. GRB 050713: ARC NIR Detections and Identification of Fading
  63. GRB050713: possible I-band afterglow
  64. GRB 050713: Swift detection of Bright Burst
  65. GRB 050713A: ROTSE-III Optical Limits
  66. GRB050712: XRT refined analysis
  67. GRB050709: Radio Observations
  68. GRB 050709: Swift UVOT and XRT observations
  69. GRB 050712: Swift-BAT Refined Analysis
  70. GRB050712: UVOT candidate optical counterpart
  71. GRB 050712: Swift XRT afterglow position
  72. GRB 050712: Swift detection of a weak burst
  73. GRB 050709: LCO40 Observations
  74. GRB050709, optical observations
  75. GRB050709: A Possible Short-Hard GRB Localized by HETE
  76. PROMPT Rc Observations of GRB 050709
  77. GRB 050525a: PROMPT VRcIc Detections
  78. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  79. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  80. GRB 050626 optical observations
  81. GRB 050626: Swift XRT observations
  82. GRB 050701
  83. GRB 050701, optical observations
  84. GRB 050408: ARC 3.5-meter NIR Observations
  85. GRB 050701: Refined XRT analysis
  86. Swift UVOT observations of GRB 050701
  87. GRB050701: Swift-BAT Refined analysis
  88. GRB 050701: Swift XRT afterglow position
  89. Swift trigger 143708 is really GRB 050701
  90. GRB 050607, radio observations
  91. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  92. GRB 050626 - Correction to GCN 3552
  93. GRB 050626 - a long GRB detected with INTEGRAL
  94. GRB 050525A: Swift Late-Time Decay Rate
  95. GRB050525a: HST Observations
  96. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  97. H3804: A Possible New XRB Detected by HETE
  98. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  99. XRF 050509c: Optical monitoring
  100. Konus-Wind observation of an intermediate burst from SGR 1806-20

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