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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 050922C: further VLT observations
  2. GRB 050820A: NIR photometry at the TNG
  3. GRB050922C: UVES/VLT high resolution spectroscopy
  4. GRB050925: Swift/XRT limits
  5. GRB/SGR 050925: IR Observations
  6. GRB050922C - Swift UVOT preliminary analysis
  7. GRB 050922C: break in the lightcurve
  8. GRB 050925: WSRT Radio Observations
  9. GRB050925: Swift UVOT upper limits
  10. Refined analysis of the Swift-BAT soft short burst
  11. GRB 050925 : I-band observation at Xinglong observatory
  12. GRB050925: Faulkes Telescope North R-band limit
  13. GRB050925: Swift-BAT detection of a short burst
  14. GRB 050922B: Correction to BAT refined analysis, longer burst
  15. GRB050922C: TNG spectroscopic observations
  16. GRB050922B: refined XRT analysis
  17. Konus-Wind observation of GRB 050922C
  18. GRB 050922C: Refined redshift
  19. GRB050922B: Swift UVOT early upper limits.
  20. GRB OT observation
  21. GRB050922C: observation at MonteBoo
  22. INT 2.5m limit for GRB050922B
  23. GRB 050922B: optical limit
  24. GRB050922C: Optical Observations
  25. GRB 050922C: Swift XRT refined analysis
  26. HETE Fregate observations of GRB 050922C
  27. GRB 050922C: Swift-BAT refined analysis
  28. GRB 050922B: Swift-BAT refined analysis
  29. GRB050922C: optical observations
  30. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  31. GRB 050922C: optical obserations
  32. GRB 050922C: NOT optical observations
  33. GRB 050922A: Analysis of Swift/XRT TOO observation
  34. GRB 050922C: Swift detection of a bright burst
  35. GRB 050922C: ROTSE-IIId Refined Analysis
  36. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  37. GRB 050922B: ROTSE-III Optical Limits
  38. GRB 050922B,optical observation
  39. GRB050922B: Swift-BAT detection of a weak long burst
  40. Possible GRB 050922 detected by INTEGRAL
  41. GRB050918: Possible Swift/XRT detected afterglow
  42. GRB050820B: analysis of the XMM-Newton observation
  43. GRB050916: Swift/UVOT Upper Limits
  44. GRB 050916: Swift-BAT refined analysis
  45. GRB 050918 - A long GRB detected by INTEGRAL
  46. GRB 050915a: Radio Observations
  47. Swift-BAT trigger 155764 is not a GRB
  48. Swift-BAT trigger 155764 is probably not a GRB
  49. Swift trigger 155764: bad XRT centroid
  50. Swift-BAT trigger 155535 is definitely not a GRB
  51. GRB050916 : Swift-XRT refined analysis
  52. GRB 050916: XRT position
  53. GRB 050915b, SMARTS optical/IR observations of the XRT position
  54. GRB 050915B: Swift-BAT refined analysis
  55. GRB 050915B: Swift/UVOT Upper Limits
  56. GRB050916: Swift-BAT detection of a long weak burst
  57. GRB 050915a: IR Transient
  58. GRB 050915B: XRT position
  59. GRB 050915b, SMARTS optical/IR observations
  60. GRB050915B: Swift-BAT detection of a long bright burst
  61. GRB050915: Swift/UVOT upper limits
  62. GRB 050915: KAIT optical limit
  63. GRB 050915: IR Observations
  64. GRB 050915: Swift XRT refined analysis
  65. GRB 050915: Swift-BAT refined analysis
  66. GRB050915: P60 Optical Observations
  67. GRB050915, optical observations
  68. GRB050915: XRT position
  69. GRB 050915: ROTSE-III optical limits
  70. GRB 050915: Swift detection of a GRB
  71. GRB050911: Upper limit on X-ray afterglow
  72. Swift-BAT trigger 155072 ground analysis
  73. Swift-BAT trigger 155072 is probably not a GRB
  74. GRB050914: XRT position probably due to cosmic ray
  75. GRB 050911: LCO limits on a variable source
  76. GRB 050908: DEIMOS spectrum and further analysis
  77. Swift is in normal operation
  78. GRB050911: Swift UVOT followup observations
  79. GRB 050911, optical content of Swift/XRT error box
  80. GRB050911: Swift-XRT position
  81. GRB 050911: LCO observations
  82. GRB 050911, optical observations
  83. GRB 050911: Swift-BAT refined analysis
  84. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  85. GRB 050911: z~0.16 cluster in the field
  86. GRB050911: Swift-BAT detection of a long burst
  87. GRB050908: detection of Swift/UVOT optical counterpart
  88. GRB 050910a: TAROT early optical limits
  89. RBO GRB 050908 observations
  90. WIRO observations in I of GRB 050908
  91. GRB 050906: Possible X-ray Counterpart
  92. GRB 050906: RTT150 optical observations
  93. GRB050908: Swift/UVOT Early upper limits
  94. GRB050908: VLT R-band decay index.
  95. GRB050908 : Swift-XRT refined analysis
  96. GRB 050908: Swift-BAT refined analysis
  97. GRB 050908: Optical observations
  98. Gemini Spectroscopy of GRB 050908
  99. GRB 050908: spectroscopic redshift
  100. GRB 050908: Prompt PROMPT Observations

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