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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 060223: Swift detection of a burst
  2. Spectral properties of GRB060218/SN2006aj
  3. GRB 060219: Swift-BAT refined analysis
  4. GRB 060218: rebrightening
  5. GRB 060218: emergence of the underlying SN spectrum
  6. GRB 060218: Decline in r-band flux
  7. GRB 060218: spectroscopic observations
  8. GRB 060218: Further refined analysis of the Swift-BAT burst
  9. GRB 060218: Likely an underluminous GRB
  10. GRB060218: Optical Spectroscopy of GRB-SN
  11. GRB060218: VLT spectroscopy
  12. GRB 060218: Optical Observations at Xinglong Obs.
  13. GRB 060219: SDSS galaxy inside XRT error circle
  14. GRB060218: UV Detection and Light Curves
  15. GRB060219: SARA Observations
  16. GRB 060219: Swift/UVOT Upper Limits
  17. GRB 060219: Swift-XRT Team refined analysis
  18. GRB 051221B: Swift-XRT Team Refined Analysis
  19. GRB 060219: Partial refined analysis of the Swift-BAT burst
  20. GRB060218: Radio Afterglow Discovery
  21. GRB 060219: Swift-XRT position typo correction
  22. GRB 060218: MDM Redshift
  23. GRB 060219: Swift-XRT position
  24. GRB 060218: optical/nIR observations at La Palma
  25. GRB060219: SDSS pre-burst observations
  26. GRB 060219: Swift-BAT detection of a weak burst
  27. Oddball GRB 060218, transient or GRB?
  28. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  29. Brightening of the Optical Counterpart of the Possible GRB 060218
  30. GRB 060218: MDM Observations
  31. GRB 060218: Pre-burst detection of a possible host galaxy
  32. GRB 060218A: ROTSE-III Possible Optical Flare
  33. GRB060218: Swift/XRT refined position of a possible burst
  34. Preliminary refined analysis of the Swift-BAT trigger 191157
  35. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  36. GRB 060211B: Swift/UVOT Upper Limits
  37. GRB060218 : SDSS pre-burst observations
  38. GRB 060218: Swift XRT Position
  39. GRB 060218: Swift-BAT detection of a possible burst
  40. GRB 060213: optical afterglow not confirmed
  41. Swift UVOT observations of GRB060213
  42. GRB 060211B: Skynet Observations
  43. GRB 060213: optical afterglow candidate
  44. GRB060213: Swift XRT observations and possible afterglow candidate
  45. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  46. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  47. GRB060213: MASTER final result
  48. GRB 060211b: WIRO NIR Observations
  49. GRB060213:_MASTER_optical_observation
  50. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  51. Konus-Wind observation of bright hard GRB 060213
  52. GRB 060213: IPN localization
  53. GRB 060210: Radio Observations
  54. GRB 060211a: WIRO NIR Observations
  55. GRB060211B: REM optical and NIR observations
  56. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  57. GRB 060211A: Further refined analysis of the Swift burst
  58. GRB060121: optical observations
  59. GRB060110: optical observations
  60. GRB060105: optical observations
  61. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  62. GRB 060211b: P60 Observations
  63. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  64. GRB 060206: SOAR Detections
  65. GRB 050826: Optical Afterglow and Host Galaxy
  66. GRB 060210: Further refined analysis of the Swift-BAT burst
  67. GRB 060211B: Swift/BAT refined analysis
  68. GRB060210: Swift/UVOT Upper Limits
  69. GRB 060211B: Swift-XRT Team refined analysis
  70. GRB060211b: optical observation
  71. GRB060211B: Swift/XRT position
  72. GRB 060210: Optical Observations
  73. GRB060211.7: MASTER_optical_observation under the snow
  74. GRB 060211A: Swift XRT Team Refined Analysis
  75. GRB 060211B: Swift-BAT detection of a burst
  76. GRB060211: Faulkes North observation
  77. GRB 060211: ROTSE-III Optical Limits
  78. GRB 060211: Swift detection of a long burst
  79. GRB 060210: Refined analysis of the Swift-BAT burst
  80. GRB060210: Swift XRT Refined Analysis
  81. GRB060206, optical observations
  82. GRB 060210 : Xinglong and Lulin optical limit
  83. GRB060210: Optical Observations
  84. GRB060210: Gemini absorption spectroscopy
  85. GRB060210: Early Optical Observations
  86. GRB 060210: optical evolution
  87. GRB060210:Faulkes Telescope North Afterglow Confirmation
  88. GRB 060210: candidate afterglow
  89. GRB 060210: Swift detection of a burst
  90. GRB060210: Optical afterglow
  91. GRB 060206: Swift/UVOT Observations
  92. Swift-BAT trigger 180931 is not a GRB
  93. GRB060209: RTT150 optical observations
  94. GRB 060209 : TAROT optical observation
  95. GRB060209A: MASTER optical observation
  96. GRB 060209(?): Swift-BAT detection of a possible burst
  97. GRB 060206: near-infrared observations (JK' imaging)
  98. GRB 060206: WSRT Radio Observations
  99. GRB 060203: Swift/UVOT upper limits
  100. GRB 060206: TTT Observations

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