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

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