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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 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  2. GRB050724: Further Radio Observations
  3. GRB 050726: early Swift XRT analysis results
  4. GRB050726: Swift-BAT detection of a weak burst
  5. GRB 050724: Optical Variability in Nearby Galaxy
  6. GRB 050724: J-band observations
  7. GRB 050724: GMOS Imaging and Spectroscopy
  8. GRB 050724: SWIFT XRT refined position
  9. RXTE ASM Detection of GRB050724
  10. GRB050724: Radio Observation
  11. GRB 050724: spectroscopy of object in the XRT error circle
  12. GRB 050724: Optical limit
  13. GRB 050724: optical and near-IR observations
  14. GRB 050724: Optical imaging/astrometry
  15. GRB 050724: RTT150 optical observations
  16. GRB 050724: Swift/UVOT Upper Limit
  17. GRB 050724: early Swift XRT analysis results
  18. GRB 050724 : Lulin early R-band monitoring observations
  19. GRB050724: Refined analysis of the Swift-BAT possible short burst
  20. GRB 050724: possible host galaxy in DSS
  21. GRB050724: a short-burst detected by Swift
  22. Swift-BAT trigger 147325 is not due to a real GRB
  23. GRB050723: XRT distributed coordinates are not related to the burst
  24. GRB 050721: early afterglow light curve
  25. GRB 050721A: Swift-BAT refined analysis
  26. Correction to GCN Circ 3474 on GRB050525A
  27. GRB 050721A: Early Swift XRT analysis results
  28. GRB050721A: optical decay
  29. GRB 050721: optical afterglow confirmed
  30. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  31. GRB 050721a: Optical Observations
  32. GRB050721A: Swift-BAT detection of a weak burst
  33. GRB 050709: Refined Spectral and Temporal Properties
  34. GRB 050717: PROMPT RcIc Observations
  35. GRB050714b: Radio Observation
  36. GRB050712: Radio Observations
  37. GRB 050714a: Refined XRT analysis and afterglow confirmation
  38. GRB050713a: Radio Observation
  39. Swift-BAT trigger 146731 is not a real GRB
  40. GRB 050712, Tautenburg optical afterglow observations
  41. Swift-BAT detection of a possible GRB
  42. GRB 050714B: VLT R-band observations
  43. GRB 050717: Additional LCO observations
  44. GRB050717
  45. GRB 050716; J-band observations
  46. Konus-Wind observation of GRB 050717
  47. GRB 050717: LCO near-IR observations
  48. Swift/UVOT Observations of GRB 050717
  49. GRB 050717: Swift-BAT refined analysis
  50. GRB 050717: Refined XRT analysis.
  51. GRB050712: optical limits
  52. GRB050717: Swift XRT position
  53. Swift detection of GRB 050717
  54. GRB 050716 - UKIRT identification of candidate afterglow
  55. Swift UVOT Observations of GRB 050716
  56. GRB 050716: Refined XRT analysis.
  57. GRB050716: Refined analysis of the Swift-BAT burst
  58. GRB 050716: Lulin B and R band optical observations
  59. GRB050716, optical observation
  60. GRB 050716: Optical Observations
  61. GRB050716: Faulkes North Telescope observation
  62. GRB050716: Correction to sign in XRT coordinate
  63. Swift/BAT detection of GRB 050716
  64. GRB050715: Refined analysis of the Swift-BAT burst
  65. GRB 050715: Swift-BAT detection
  66. Swift UVOT Observations of GRB 050714B
  67. Konus-Wind observation of GRB 050713A
  68. GRB 050714B: refined XRT analysis
  69. GRB 050713b: RTT150 optical observations
  70. GRB 050714B: candidate afterglow does not fade
  71. GRB050714B: Refined analysis of the Swift-BAT burst
  72. GRB 050714B: optical afterglow
  73. Swift detection of a long transient (GRB 050714B?)
  74. GRB 050709: optical afterglow candidate
  75. GRB 050714, R-band candidate
  76. GRB 050714: Swift XRT afterglow position
  77. GRB 050714, optical observations
  78. GRB 050714A: ROTSE-III Optical Limits
  79. GRB 050714 - A long GRB detected with INTEGRAL
  80. GRB 050713A: XRT refined analysis
  81. GRB 050709: Spectroscopy
  82. GRB 050713A: RAPTOR detection of early optical emission
  83. GRB050713B :Swift/UVOT observations
  84. GRB050713b: XRT refined analysis
  85. GRB050712: TNG R-band observations
  86. GRB 050713B: Swift-BAT Refined Analysis
  87. Swift-BAT Trigger 145729 is not a GRB
  88. GRB 050713A: Swift/UVOT observation
  89. GRB 050713A : Swift-BAT Refined Analysis
  90. GRB050712: Swift UVOT Observation of Afterglow Emission
  91. GRB 050713A : Lulin R-band observation
  92. GRB 050713A XMM-Newton observation
  93. GRB 050713b : Lulin R-band observations
  94. GRB050713B: Faulkes North Telescope observation
  95. RBO RI observations of GRB 050713A
  96. GRB 050713B
  97. GRB050709 : Chandra source optical counterpart
  98. GRB050713: Liverpool Telescope prompt observations
  99. GRB 050712, optical observations
  100. GRB 050713 : Planned XMM-Newton observation

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