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

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