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

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