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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 050709: PROMPT Rc Observations
  2. GRB050713b: Maidanak optical observations
  3. GRB 050724: Secure Host Redshift from Keck
  4. GRB 050724: WHT optical observations
  5. GRB050726: Swift UVOT observations
  6. GRB 050724: Chandra Observations of the X-ray Afterglow
  7. GRB050724: Refined Radio Position
  8. GRB050713: analysis of the XMM-Newton observation
  9. GRB 050724, SMARTS optical/IR afterglow observations
  10. GRB 050726, SMARTS optical/IR observations
  11. Swift-BAT trigger 147918 is not a real GRB
  12. GRB 050727: RTT150 optical observations
  13. GRB050724: VLT observations of the variable source
  14. GRB050727: KAIT optical limit
  15. GRB050709: Second Epoch Chandra Observation
  16. GRB 050726: PROMPT Rc Observations
  17. GRB050709: Second Epoch Chandra Observation
  18. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  19. GRB050724: Further Radio Observations
  20. GRB 050726: early Swift XRT analysis results
  21. GRB050726: Swift-BAT detection of a weak burst
  22. GRB 050724: Optical Variability in Nearby Galaxy
  23. GRB 050724: J-band observations
  24. GRB 050724: GMOS Imaging and Spectroscopy
  25. GRB 050724: SWIFT XRT refined position
  26. RXTE ASM Detection of GRB050724
  27. GRB050724: Radio Observation
  28. GRB 050724: spectroscopy of object in the XRT error circle
  29. GRB 050724: Optical limit
  30. GRB 050724: optical and near-IR observations
  31. GRB 050724: Optical imaging/astrometry
  32. GRB 050724: RTT150 optical observations
  33. GRB 050724: Swift/UVOT Upper Limit
  34. GRB 050724: early Swift XRT analysis results
  35. GRB 050724 : Lulin early R-band monitoring observations
  36. GRB050724: Refined analysis of the Swift-BAT possible short burst
  37. GRB 050724: possible host galaxy in DSS
  38. GRB050724: a short-burst detected by Swift
  39. Swift-BAT trigger 147325 is not due to a real GRB
  40. GRB050723: XRT distributed coordinates are not related to the burst
  41. GRB 050721: early afterglow light curve
  42. GRB 050721A: Swift-BAT refined analysis
  43. Correction to GCN Circ 3474 on GRB050525A
  44. GRB 050721A: Early Swift XRT analysis results
  45. GRB050721A: optical decay
  46. GRB 050721: optical afterglow confirmed
  47. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  48. GRB 050721a: Optical Observations
  49. GRB050721A: Swift-BAT detection of a weak burst
  50. GRB 050709: Refined Spectral and Temporal Properties
  51. GRB 050717: PROMPT RcIc Observations
  52. GRB050714b: Radio Observation
  53. GRB050712: Radio Observations
  54. GRB 050714a: Refined XRT analysis and afterglow confirmation
  55. GRB050713a: Radio Observation
  56. Swift-BAT trigger 146731 is not a real GRB
  57. GRB 050712, Tautenburg optical afterglow observations
  58. Swift-BAT detection of a possible GRB
  59. GRB 050714B: VLT R-band observations
  60. GRB 050717: Additional LCO observations
  61. GRB050717
  62. GRB 050716; J-band observations
  63. Konus-Wind observation of GRB 050717
  64. GRB 050717: LCO near-IR observations
  65. Swift/UVOT Observations of GRB 050717
  66. GRB 050717: Swift-BAT refined analysis
  67. GRB 050717: Refined XRT analysis.
  68. GRB050712: optical limits
  69. GRB050717: Swift XRT position
  70. Swift detection of GRB 050717
  71. GRB 050716 - UKIRT identification of candidate afterglow
  72. Swift UVOT Observations of GRB 050716
  73. GRB 050716: Refined XRT analysis.
  74. GRB050716: Refined analysis of the Swift-BAT burst
  75. GRB 050716: Lulin B and R band optical observations
  76. GRB050716, optical observation
  77. GRB 050716: Optical Observations
  78. GRB050716: Faulkes North Telescope observation
  79. GRB050716: Correction to sign in XRT coordinate
  80. Swift/BAT detection of GRB 050716
  81. GRB050715: Refined analysis of the Swift-BAT burst
  82. GRB 050715: Swift-BAT detection
  83. Swift UVOT Observations of GRB 050714B
  84. Konus-Wind observation of GRB 050713A
  85. GRB 050714B: refined XRT analysis
  86. GRB 050713b: RTT150 optical observations
  87. GRB 050714B: candidate afterglow does not fade
  88. GRB050714B: Refined analysis of the Swift-BAT burst
  89. GRB 050714B: optical afterglow
  90. Swift detection of a long transient (GRB 050714B?)
  91. GRB 050709: optical afterglow candidate
  92. GRB 050714, R-band candidate
  93. GRB 050714: Swift XRT afterglow position
  94. GRB 050714, optical observations
  95. GRB 050714A: ROTSE-III Optical Limits
  96. GRB 050714 - A long GRB detected with INTEGRAL
  97. GRB 050713A: XRT refined analysis
  98. GRB 050709: Spectroscopy
  99. GRB 050713A: RAPTOR detection of early optical emission
  100. GRB050713B :Swift/UVOT observations

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