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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 060223a: Swift/UVOT refined analysis
  2. GRB 060223: Swift XRT Team preliminary analysis
  3. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  4. GRB 060223B: Swift detection of a bright burst
  5. GRB 060223: Swift-BAT refined analysis
  6. GRB 060218: rebrightening
  7. Correction to GCN 4816 on GRB060218
  8. GRB 060218/SN 2006aj: optical observations
  9. GRB060218: Optical brightening in V and R
  10. GRB 060223: Keck redshift
  11. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  12. GRB 060223: Swift detection of a burst
  13. Spectral properties of GRB060218/SN2006aj
  14. GRB 060219: Swift-BAT refined analysis
  15. GRB 060218: rebrightening
  16. GRB 060218: emergence of the underlying SN spectrum
  17. GRB 060218: Decline in r-band flux
  18. GRB 060218: spectroscopic observations
  19. GRB 060218: Further refined analysis of the Swift-BAT burst
  20. GRB 060218: Likely an underluminous GRB
  21. GRB060218: Optical Spectroscopy of GRB-SN
  22. GRB060218: VLT spectroscopy
  23. GRB 060218: Optical Observations at Xinglong Obs.
  24. GRB 060219: SDSS galaxy inside XRT error circle
  25. GRB060218: UV Detection and Light Curves
  26. GRB060219: SARA Observations
  27. GRB 060219: Swift/UVOT Upper Limits
  28. GRB 060219: Swift-XRT Team refined analysis
  29. GRB 051221B: Swift-XRT Team Refined Analysis
  30. GRB 060219: Partial refined analysis of the Swift-BAT burst
  31. GRB060218: Radio Afterglow Discovery
  32. GRB 060219: Swift-XRT position typo correction
  33. GRB 060218: MDM Redshift
  34. GRB 060219: Swift-XRT position
  35. GRB 060218: optical/nIR observations at La Palma
  36. GRB060219: SDSS pre-burst observations
  37. GRB 060219: Swift-BAT detection of a weak burst
  38. Oddball GRB 060218, transient or GRB?
  39. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  40. Brightening of the Optical Counterpart of the Possible GRB 060218
  41. GRB 060218: MDM Observations
  42. GRB 060218: Pre-burst detection of a possible host galaxy
  43. GRB 060218A: ROTSE-III Possible Optical Flare
  44. GRB060218: Swift/XRT refined position of a possible burst
  45. Preliminary refined analysis of the Swift-BAT trigger 191157
  46. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  47. GRB 060211B: Swift/UVOT Upper Limits
  48. GRB060218 : SDSS pre-burst observations
  49. Subject: GRB 060218: Swift XRT Position
  50. GRB 060218: Swift-BAT detection of a possible burst
  51. GRB 060213: optical afterglow not confirmed
  52. Swift UVOT observations of GRB060213
  53. GRB 060211B: Skynet Observations
  54. GRB 060213: optical afterglow candidate
  55. GRB060213: Swift XRT observations and possible afterglow candidate
  56. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  57. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  58. GRB060213: MASTER final result
  59. GRB 060211b: WIRO NIR Observations
  60. GRB060213:_MASTER_optical_observation
  61. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  62. Konus-Wind observation of bright hard GRB 060213
  63. GRB 060213: IPN localization
  64. GRB 060210: Radio Observations
  65. GRB 060211a: WIRO NIR Observations
  66. GRB060211B: REM optical and NIR observations
  67. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  68. GRB 060211A: Further refined analysis of the Swift burst
  69. GRB060121: optical observations
  70. GRB060110: optical observations
  71. GRB060105: optical observations
  72. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  73. GRB 060211b: P60 Observations
  74. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  75. GRB 060206: SOAR Detections
  76. GRB 050826: Optical Afterglow and Host Galaxy
  77. GRB 060210: Further refined analysis of the Swift-BAT burst
  78. GRB 060211B: Swift/BAT refined analysis
  79. GRB060210: Swift/UVOT Upper Limits
  80. GRB 060211B: Swift-XRT Team refined analysis
  81. GRB060211b: optical observation
  82. GRB060211B: Swift/XRT position
  83. GRB 060210: Optical Observations
  84. GRB060211.7: MASTER_optical_observation under the snow
  85. GRB 060211A: Swift XRT Team Refined Analysis
  86. GRB 060211B: Swift-BAT detection of a burst
  87. GRB060211: Faulkes North observation
  88. GRB 060211: ROTSE-III Optical Limits
  89. GRB 060211: Swift detection of a long burst
  90. GRB 060210: Refined analysis of the Swift-BAT burst
  91. GRB060210: Swift XRT Refined Analysis
  92. GRB060206, optical observations
  93. GRB 060210 : Xinglong and Lulin optical limit
  94. GRB060210: Optical Observations
  95. GRB060210: Gemini absorption spectroscopy
  96. GRB060210: Early Optical Observations
  97. GRB 060210: optical evolution
  98. GRB060210:Faulkes Telescope North Afterglow Confirmation
  99. GRB 060210: candidate afterglow
  100. GRB 060210: Swift detection of a burst

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