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

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