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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. GRB050802: CrAO optical observations
  2. GRB050801: Unchanged decay slope
  3. GRB050802 radio non-detection
  4. GRB 050730: OHP optical observations
  5. GRB 050802: early Swift XRT analysis results
  6. GRB 050802: Swift/UVOT observations
  7. GRB 050802 : Lulin Optical follow-up observation
  8. GRB 050802: Swift-BAT refined analysis
  9. GRB050801: Optical photometry and decay index
  10. GRB 050802: XRT position
  11. GRB 050802: Swift Gamma-ray Burst
  12. GRB050801: Swift/UVOT Optical and UV detections
  13. GRB 050730: Preliminary Analysis of MIKE Spectrum
  14. GCN 050801: early Swift XRT analysis results
  15. GRB 050801: Swift-BAT refined analysis
  16. GRB 050801, SMARTS optical/IR afterglow observations
  17. GRB 050801, afterglow observations
  18. GRB 050730, corrected photometry and break?
  19. GRB 050801: ROTSE-III Early Afterglow Break
  20. GRB050801: Swift-BAT detection of a burst
  21. GRB050801: GCN XRT position is incorrect
  22. GRB 050801: ROTSE-III Detection of Possible Counterpart
  23. GRB 050730: XRT refined analysis
  24. Correction to GCN Circ 3476 on GRB050525A
  25. GRB 050730: early TAROT optical observations
  26. GRB 050726: PROMPT Rc Observations
  27. GRB 050730: RTT150 optical observations
  28. Swift/UVOT photometry of GRB050730
  29. GRB 050730, spectra and optical photometry
  30. GRB050730: Refined BAT analysis of the Swift-BAT burst
  31. GRB 050730: Swift XRT afterglow observations
  32. GRB 050730 XMM-Newton observation
  33. GRB 050730: PROMPT VRcIc Observations
  34. GRB050730, afterglow observations
  35. GRB050730: confirmation of redshift
  36. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  37. GRB 050730, SMARTS optical/IR afterglow observations
  38. GRB 050730 : Planned XMM-Newton observation
  39. GRB050730: Liverpool Telescope optical observations
  40. GRB 050730, optical candidate
  41. GRB050730: Swift-BAT detection of a weak burst
  42. GRB 050713A: Swift XRT extended light curve
  43. GRB 050709: PROMPT Rc Observations
  44. GRB050713b: Maidanak optical observations
  45. GRB 050724: Secure Host Redshift from Keck
  46. GRB 050724: WHT optical observations
  47. GRB050726: Swift UVOT observations
  48. GRB 050724: Chandra Observations of the X-ray Afterglow
  49. GRB050724: Refined Radio Position
  50. GRB050713: analysis of the XMM-Newton observation
  51. GRB 050724, SMARTS optical/IR afterglow observations
  52. GRB 050726, SMARTS optical/IR observations
  53. Swift-BAT trigger 147918 is not a real GRB
  54. GRB 050727: RTT150 optical observations
  55. GRB050724: VLT observations of the variable source
  56. GRB050727: KAIT optical limit
  57. GRB050709: Second Epoch Chandra Observation
  58. GRB 050726: PROMPT Rc Observations
  59. GRB050709: Second Epoch Chandra Observation
  60. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  61. GRB050724: Further Radio Observations
  62. GRB 050726: early Swift XRT analysis results
  63. GRB050726: Swift-BAT detection of a weak burst
  64. GRB 050724: Optical Variability in Nearby Galaxy
  65. GRB 050724: J-band observations
  66. GRB 050724: GMOS Imaging and Spectroscopy
  67. GRB 050724: SWIFT XRT refined position
  68. RXTE ASM Detection of GRB050724
  69. GRB050724: Radio Observation
  70. GRB 050724: spectroscopy of object in the XRT error circle
  71. GRB 050724: Optical limit
  72. GRB 050724: optical and near-IR observations
  73. GRB 050724: Optical imaging/astrometry
  74. GRB 050724: RTT150 optical observations
  75. GRB 050724: Swift/UVOT Upper Limit
  76. GRB 050724: early Swift XRT analysis results
  77. GRB 050724 : Lulin early R-band monitoring observations
  78. GRB050724: Refined analysis of the Swift-BAT possible short burst
  79. GRB 050724: possible host galaxy in DSS
  80. GRB050724: a short-burst detected by Swift
  81. Swift-BAT trigger 147325 is not due to a real GRB
  82. GRB050723: XRT distributed coordinates are not related to the burst
  83. GRB 050721: early afterglow light curve
  84. GRB 050721A: Swift-BAT refined analysis
  85. Correction to GCN Circ 3474 on GRB050525A
  86. GRB 050721A: Early Swift XRT analysis results
  87. GRB050721A: optical decay
  88. GRB 050721: optical afterglow confirmed
  89. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  90. GRB 050721a: Optical Observations
  91. GRB050721A: Swift-BAT detection of a weak burst
  92. GRB 050709: Refined Spectral and Temporal Properties
  93. GRB 050717: PROMPT RcIc Observations
  94. GRB050714b: Radio Observation
  95. GRB050712: Radio Observations
  96. GRB 050714a: Refined XRT analysis and afterglow confirmation
  97. GRB050713a: Radio Observation
  98. Swift-BAT trigger 146731 is not a real GRB
  99. GRB 050712, Tautenburg optical afterglow observations
  100. Swift-BAT detection of a possible GRB

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