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

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