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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 060219: Swift-BAT refined analysis
  2. GRB 060218: rebrightening
  3. GRB 060218: emergence of the underlying SN spectrum
  4. GRB 060218: Decline in r-band flux
  5. GRB 060218: spectroscopic observations
  6. GRB 060218: Further refined analysis of the Swift-BAT burst
  7. GRB 060218: Likely an underluminous GRB
  8. GRB060218: Optical Spectroscopy of GRB-SN
  9. GRB060218: VLT spectroscopy
  10. GRB 060218: Optical Observations at Xinglong Obs.
  11. GRB 060219: SDSS galaxy inside XRT error circle
  12. GRB060218: UV Detection and Light Curves
  13. GRB060219: SARA Observations
  14. GRB 060219: Swift/UVOT Upper Limits
  15. GRB 060219: Swift-XRT Team refined analysis
  16. GRB 051221B: Swift-XRT Team Refined Analysis
  17. GRB 060219: Partial refined analysis of the Swift-BAT burst
  18. GRB060218: Radio Afterglow Discovery
  19. GRB 060219: Swift-XRT position typo correction
  20. GRB 060218: MDM Redshift
  21. GRB 060219: Swift-XRT position
  22. GRB 060218: optical/nIR observations at La Palma
  23. GRB060219: SDSS pre-burst observations
  24. GRB 060219: Swift-BAT detection of a weak burst
  25. Oddball GRB 060218, transient or GRB?
  26. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  27. Brightening of the Optical Counterpart of the Possible GRB 060218
  28. GRB 060218: MDM Observations
  29. GRB 060218: Pre-burst detection of a possible host galaxy
  30. GRB 060218A: ROTSE-III Possible Optical Flare
  31. GRB060218: Swift/XRT refined position of a possible burst
  32. Preliminary refined analysis of the Swift-BAT trigger 191157
  33. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  34. GRB 060211B: Swift/UVOT Upper Limits
  35. GRB060218 : SDSS pre-burst observations
  36. GRB 060218: Swift XRT Position
  37. GRB 060218: Swift-BAT detection of a possible burst
  38. GRB 060213: optical afterglow not confirmed
  39. Swift UVOT observations of GRB060213
  40. GRB 060211B: Skynet Observations
  41. GRB 060213: optical afterglow candidate
  42. GRB060213: Swift XRT observations and possible afterglow candidate
  43. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  44. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  45. GRB060213: MASTER final result
  46. GRB 060211b: WIRO NIR Observations
  47. GRB060213:_MASTER_optical_observation
  48. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  49. Konus-Wind observation of bright hard GRB 060213
  50. GRB 060213: IPN localization
  51. GRB 060210: Radio Observations
  52. GRB 060211a: WIRO NIR Observations
  53. GRB060211B: REM optical and NIR observations
  54. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  55. GRB 060211A: Further refined analysis of the Swift burst
  56. GRB060121: optical observations
  57. GRB060110: optical observations
  58. GRB060105: optical observations
  59. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  60. GRB 060211b: P60 Observations
  61. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  62. GRB 060206: SOAR Detections
  63. GRB 050826: Optical Afterglow and Host Galaxy
  64. GRB 060210: Further refined analysis of the Swift-BAT burst
  65. GRB 060211B: Swift/BAT refined analysis
  66. GRB060210: Swift/UVOT Upper Limits
  67. GRB 060211B: Swift-XRT Team refined analysis
  68. GRB060211b: optical observation
  69. GRB060211B: Swift/XRT position
  70. GRB 060210: Optical Observations
  71. GRB060211.7: MASTER_optical_observation under the snow
  72. GRB 060211A: Swift XRT Team Refined Analysis
  73. GRB 060211B: Swift-BAT detection of a burst
  74. GRB060211: Faulkes North observation
  75. GRB 060211: ROTSE-III Optical Limits
  76. GRB 060211: Swift detection of a long burst
  77. GRB 060210: Refined analysis of the Swift-BAT burst
  78. GRB060210: Swift XRT Refined Analysis
  79. GRB060206, optical observations
  80. GRB 060210 : Xinglong and Lulin optical limit
  81. GRB060210: Optical Observations
  82. GRB060210: Gemini absorption spectroscopy
  83. GRB060210: Early Optical Observations
  84. GRB 060210: optical evolution
  85. GRB060210:Faulkes Telescope North Afterglow Confirmation
  86. GRB 060210: candidate afterglow
  87. GRB 060210: Swift detection of a burst
  88. GRB060210: Optical afterglow
  89. GRB 060206: Swift/UVOT Observations
  90. Swift-BAT trigger 180931 is not a GRB
  91. GRB060209: RTT150 optical observations
  92. GRB 060209 : TAROT optical observation
  93. GRB060209A: MASTER optical observation
  94. GRB 060209(?): Swift-BAT detection of a possible burst
  95. GRB 060206: near-infrared observations (JK' imaging)
  96. GRB 060206: WSRT Radio Observations
  97. GRB 060203: Swift/UVOT upper limits
  98. GRB 060206: TTT Observations
  99. GRB 060206: More PROMPT Detections
  100. GRB 060121 : WIDGET Pre-trigger limit

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