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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').
  1. GRB 050802: Swift Gamma-ray Burst
  2. GRB050801: Swift/UVOT Optical and UV detections
  3. GRB 050730: Preliminary Analysis of MIKE Spectrum
  4. GCN 050801: early Swift XRT analysis results
  5. GRB 050801: Swift-BAT refined analysis
  6. GRB 050801, SMARTS optical/IR afterglow observations
  7. GRB 050801, afterglow observations
  8. GRB 050730, corrected photometry and break?
  9. GRB 050801: ROTSE-III Early Afterglow Break
  10. GRB050801: Swift-BAT detection of a burst
  11. GRB050801: GCN XRT position is incorrect
  12. GRB 050801: ROTSE-III Detection of Possible Counterpart
  13. GRB 050730: XRT refined analysis
  14. Correction to GCN Circ 3476 on GRB050525A
  15. GRB 050730: early TAROT optical observations
  16. GRB 050726: PROMPT Rc Observations
  17. GRB 050730: RTT150 optical observations
  18. Swift/UVOT photometry of GRB050730
  19. GRB 050730, spectra and optical photometry
  20. GRB050730: Refined BAT analysis of the Swift-BAT burst
  21. GRB 050730: Swift XRT afterglow observations
  22. GRB 050730 XMM-Newton observation
  23. GRB 050730: PROMPT VRcIc Observations
  24. GRB050730, afterglow observations
  25. GRB050730: confirmation of redshift
  26. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  27. GRB 050730, SMARTS optical/IR afterglow observations
  28. GRB 050730 : Planned XMM-Newton observation
  29. GRB050730: Liverpool Telescope optical observations
  30. GRB 050730, optical candidate
  31. GRB050730: Swift-BAT detection of a weak burst
  32. GRB 050713A: Swift XRT extended light curve
  33. GRB 050709: PROMPT Rc Observations
  34. GRB050713b: Maidanak optical observations
  35. GRB 050724: Secure Host Redshift from Keck
  36. GRB 050724: WHT optical observations
  37. GRB050726: Swift UVOT observations
  38. GRB 050724: Chandra Observations of the X-ray Afterglow
  39. GRB050724: Refined Radio Position
  40. GRB050713: analysis of the XMM-Newton observation
  41. GRB 050724, SMARTS optical/IR afterglow observations
  42. GRB 050726, SMARTS optical/IR observations
  43. Swift-BAT trigger 147918 is not a real GRB
  44. GRB 050727: RTT150 optical observations
  45. GRB050724: VLT observations of the variable source
  46. GRB050727: KAIT optical limit
  47. GRB050709: Second Epoch Chandra Observation
  48. GRB 050726: PROMPT Rc Observations
  49. GRB050709: Second Epoch Chandra Observation
  50. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  51. GRB050724: Further Radio Observations
  52. GRB 050726: early Swift XRT analysis results
  53. GRB050726: Swift-BAT detection of a weak burst
  54. GRB 050724: Optical Variability in Nearby Galaxy
  55. GRB 050724: J-band observations
  56. GRB 050724: GMOS Imaging and Spectroscopy
  57. GRB 050724: SWIFT XRT refined position
  58. RXTE ASM Detection of GRB050724
  59. GRB050724: Radio Observation
  60. GRB 050724: spectroscopy of object in the XRT error circle
  61. GRB 050724: Optical limit
  62. GRB 050724: optical and near-IR observations
  63. GRB 050724: Optical imaging/astrometry
  64. GRB 050724: RTT150 optical observations
  65. GRB 050724: Swift/UVOT Upper Limit
  66. GRB 050724: early Swift XRT analysis results
  67. GRB 050724 : Lulin early R-band monitoring observations
  68. GRB050724: Refined analysis of the Swift-BAT possible short burst
  69. GRB 050724: possible host galaxy in DSS
  70. GRB050724: a short-burst detected by Swift
  71. Swift-BAT trigger 147325 is not due to a real GRB
  72. GRB050723: XRT distributed coordinates are not related to the burst
  73. GRB 050721: early afterglow light curve
  74. GRB 050721A: Swift-BAT refined analysis
  75. Correction to GCN Circ 3474 on GRB050525A
  76. GRB 050721A: Early Swift XRT analysis results
  77. GRB050721A: optical decay
  78. GRB 050721: optical afterglow confirmed
  79. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  80. GRB 050721a: Optical Observations
  81. GRB050721A: Swift-BAT detection of a weak burst
  82. GRB 050709: Refined Spectral and Temporal Properties
  83. GRB 050717: PROMPT RcIc Observations
  84. GRB050714b: Radio Observation
  85. GRB050712: Radio Observations
  86. GRB 050714a: Refined XRT analysis and afterglow confirmation
  87. GRB050713a: Radio Observation
  88. Swift-BAT trigger 146731 is not a real GRB
  89. GRB 050712, Tautenburg optical afterglow observations
  90. Swift-BAT detection of a possible GRB
  91. GRB 050714B: VLT R-band observations
  92. GRB 050717: Additional LCO observations
  93. GRB050717
  94. GRB 050716; J-band observations
  95. Konus-Wind observation of GRB 050717
  96. GRB 050717: LCO near-IR observations
  97. Swift/UVOT Observations of GRB 050717
  98. GRB 050717: Swift-BAT refined analysis
  99. GRB 050717: Refined XRT analysis.
  100. GRB050712: optical limits

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