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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. GRB050922C: UVES/VLT high resolution spectroscopy
  2. GRB050925: Swift/XRT limits
  3. GRB/SGR 050925: IR Observations
  4. GRB050922C - Swift UVOT preliminary analysis
  5. GRB 050922C: break in the lightcurve
  6. GRB 050925: WSRT Radio Observations
  7. GRB050925: Swift UVOT upper limits
  8. Refined analysis of the Swift-BAT soft short burst
  9. GRB 050925 : I-band observation at Xinglong observatory
  10. GRB050925: Faulkes Telescope North R-band limit
  11. GRB050925: Swift-BAT detection of a short burst
  12. GRB 050922B: Correction to BAT refined analysis, longer burst
  13. GRB050922C: TNG spectroscopic observations
  14. GRB050922B: refined XRT analysis
  15. Konus-Wind observation of GRB 050922C
  16. GRB 050922C: Refined redshift
  17. GRB050922B: Swift UVOT early upper limits.
  18. GRB OT observation
  19. GRB050922C: observation at MonteBoo
  20. INT 2.5m limit for GRB050922B
  21. GRB 050922B: optical limit
  22. GRB050922C: Optical Observations
  23. GRB 050922C: Swift XRT refined analysis
  24. HETE Fregate observations of GRB 050922C
  25. GRB 050922C: Swift-BAT refined analysis
  26. GRB 050922B: Swift-BAT refined analysis
  27. GRB050922C: optical observations
  28. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  29. GRB 050922C: optical obserations
  30. GRB 050922C: NOT optical observations
  31. GRB 050922A: Analysis of Swift/XRT TOO observation
  32. GRB 050922C: Swift detection of a bright burst
  33. GRB 050922C: ROTSE-IIId Refined Analysis
  34. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  35. GRB 050922B: ROTSE-III Optical Limits
  36. GRB 050922B,optical observation
  37. GRB050922B: Swift-BAT detection of a weak long burst
  38. Possible GRB 050922 detected by INTEGRAL
  39. GRB050918: Possible Swift/XRT detected afterglow
  40. GRB050820B: analysis of the XMM-Newton observation
  41. GRB050916: Swift/UVOT Upper Limits
  42. GRB 050916: Swift-BAT refined analysis
  43. GRB 050918 - A long GRB detected by INTEGRAL
  44. GRB 050915a: Radio Observations
  45. Swift-BAT trigger 155764 is not a GRB
  46. Swift-BAT trigger 155764 is probably not a GRB
  47. Swift trigger 155764: bad XRT centroid
  48. Swift-BAT trigger 155535 is definitely not a GRB
  49. GRB050916 : Swift-XRT refined analysis
  50. GRB 050916: XRT position
  51. GRB 050915b, SMARTS optical/IR observations of the XRT position
  52. GRB 050915B: Swift-BAT refined analysis
  53. GRB 050915B: Swift/UVOT Upper Limits
  54. GRB050916: Swift-BAT detection of a long weak burst
  55. GRB 050915a: IR Transient
  56. GRB 050915B: XRT position
  57. GRB 050915b, SMARTS optical/IR observations
  58. GRB050915B: Swift-BAT detection of a long bright burst
  59. GRB050915: Swift/UVOT upper limits
  60. GRB 050915: KAIT optical limit
  61. GRB 050915: IR Observations
  62. GRB 050915: Swift XRT refined analysis
  63. GRB 050915: Swift-BAT refined analysis
  64. GRB050915: P60 Optical Observations
  65. GRB050915, optical observations
  66. GRB050915: XRT position
  67. GRB 050915: ROTSE-III optical limits
  68. GRB 050915: Swift detection of a GRB
  69. GRB050911: Upper limit on X-ray afterglow
  70. Swift-BAT trigger 155072 ground analysis
  71. Swift-BAT trigger 155072 is probably not a GRB
  72. GRB050914: XRT position probably due to cosmic ray
  73. GRB 050911: LCO limits on a variable source
  74. GRB 050908: DEIMOS spectrum and further analysis
  75. Swift is in normal operation
  76. GRB050911: Swift UVOT followup observations
  77. GRB 050911, optical content of Swift/XRT error box
  78. GRB050911: Swift-XRT position
  79. GRB 050911: LCO observations
  80. GRB 050911, optical observations
  81. GRB 050911: Swift-BAT refined analysis
  82. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  83. GRB 050911: z~0.16 cluster in the field
  84. GRB050911: Swift-BAT detection of a long burst
  85. GRB050908: detection of Swift/UVOT optical counterpart
  86. GRB 050910a: TAROT early optical limits
  87. RBO GRB 050908 observations
  88. WIRO observations in I of GRB 050908
  89. GRB 050906: Possible X-ray Counterpart
  90. GRB 050906: RTT150 optical observations
  91. GRB050908: Swift/UVOT Early upper limits
  92. GRB050908: VLT R-band decay index.
  93. GRB050908 : Swift-XRT refined analysis
  94. GRB 050908: Swift-BAT refined analysis
  95. GRB 050908: Optical observations
  96. Gemini Spectroscopy of GRB 050908
  97. GRB 050908: spectroscopic redshift
  98. GRB 050908: Prompt PROMPT Observations
  99. GRB 050908 : Swift XRT position
  100. GRB 050908: KAIT observations

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