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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 050727: RTT150 optical observations
  2. GRB050724: VLT observations of the variable source
  3. GRB050727: KAIT optical limit
  4. GRB050709: Second Epoch Chandra Observation
  5. GRB 050726: PROMPT Rc Observations
  6. GRB050709: Second Epoch Chandra Observation
  7. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  8. GRB050724: Further Radio Observations
  9. GRB 050726: early Swift XRT analysis results
  10. GRB050726: Swift-BAT detection of a weak burst
  11. GRB 050724: Optical Variability in Nearby Galaxy
  12. GRB 050724: J-band observations
  13. GRB 050724: GMOS Imaging and Spectroscopy
  14. GRB 050724: SWIFT XRT refined position
  15. RXTE ASM Detection of GRB050724
  16. GRB050724: Radio Observation
  17. GRB 050724: spectroscopy of object in the XRT error circle
  18. GRB 050724: Optical limit
  19. GRB 050724: optical and near-IR observations
  20. GRB 050724: Optical imaging/astrometry
  21. GRB 050724: RTT150 optical observations
  22. GRB 050724: Swift/UVOT Upper Limit
  23. GRB 050724: early Swift XRT analysis results
  24. GRB 050724 : Lulin early R-band monitoring observations
  25. GRB050724: Refined analysis of the Swift-BAT possible short burst
  26. GRB 050724: possible host galaxy in DSS
  27. GRB050724: a short-burst detected by Swift
  28. Swift-BAT trigger 147325 is not due to a real GRB
  29. GRB050723: XRT distributed coordinates are not related to the burst
  30. GRB 050721: early afterglow light curve
  31. GRB 050721A: Swift-BAT refined analysis
  32. Correction to GCN Circ 3474 on GRB050525A
  33. GRB 050721A: Early Swift XRT analysis results
  34. GRB050721A: optical decay
  35. GRB 050721: optical afterglow confirmed
  36. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  37. GRB 050721a: Optical Observations
  38. GRB050721A: Swift-BAT detection of a weak burst
  39. GRB 050709: Refined Spectral and Temporal Properties
  40. GRB 050717: PROMPT RcIc Observations
  41. GRB050714b: Radio Observation
  42. GRB050712: Radio Observations
  43. GRB 050714a: Refined XRT analysis and afterglow confirmation
  44. GRB050713a: Radio Observation
  45. Swift-BAT trigger 146731 is not a real GRB
  46. GRB 050712, Tautenburg optical afterglow observations
  47. Swift-BAT detection of a possible GRB
  48. GRB 050714B: VLT R-band observations
  49. GRB 050717: Additional LCO observations
  50. GRB050717
  51. GRB 050716; J-band observations
  52. Konus-Wind observation of GRB 050717
  53. GRB 050717: LCO near-IR observations
  54. Swift/UVOT Observations of GRB 050717
  55. GRB 050717: Swift-BAT refined analysis
  56. GRB 050717: Refined XRT analysis.
  57. GRB050712: optical limits
  58. GRB050717: Swift XRT position
  59. Swift detection of GRB 050717
  60. GRB 050716 - UKIRT identification of candidate afterglow
  61. Swift UVOT Observations of GRB 050716
  62. GRB 050716: Refined XRT analysis.
  63. GRB050716: Refined analysis of the Swift-BAT burst
  64. GRB 050716: Lulin B and R band optical observations
  65. GRB050716, optical observation
  66. GRB 050716: Optical Observations
  67. GRB050716: Faulkes North Telescope observation
  68. GRB050716: Correction to sign in XRT coordinate
  69. Swift/BAT detection of GRB 050716
  70. GRB050715: Refined analysis of the Swift-BAT burst
  71. GRB 050715: Swift-BAT detection
  72. Swift UVOT Observations of GRB 050714B
  73. Konus-Wind observation of GRB 050713A
  74. GRB 050714B: refined XRT analysis
  75. GRB 050713b: RTT150 optical observations
  76. GRB 050714B: candidate afterglow does not fade
  77. GRB050714B: Refined analysis of the Swift-BAT burst
  78. GRB 050714B: optical afterglow
  79. Swift detection of a long transient (GRB 050714B?)
  80. GRB 050709: optical afterglow candidate
  81. GRB 050714, R-band candidate
  82. GRB 050714: Swift XRT afterglow position
  83. GRB 050714, optical observations
  84. GRB 050714A: ROTSE-III Optical Limits
  85. GRB 050714 - A long GRB detected with INTEGRAL
  86. GRB 050713A: XRT refined analysis
  87. GRB 050709: Spectroscopy
  88. GRB 050713A: RAPTOR detection of early optical emission
  89. GRB050713B :Swift/UVOT observations
  90. GRB050713b: XRT refined analysis
  91. GRB050712: TNG R-band observations
  92. GRB 050713B: Swift-BAT Refined Analysis
  93. Swift-BAT Trigger 145729 is not a GRB
  94. GRB 050713A: Swift/UVOT observation
  95. GRB 050713A : Swift-BAT Refined Analysis
  96. GRB050712: Swift UVOT Observation of Afterglow Emission
  97. GRB 050713A : Lulin R-band observation
  98. GRB 050713A XMM-Newton observation
  99. GRB 050713b : Lulin R-band observations
  100. GRB050713B: Faulkes North Telescope observation

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