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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 060218: Optical Observations at Xinglong Obs.
  2. GRB 060219: SDSS galaxy inside XRT error circle
  3. GRB060218: UV Detection and Light Curves
  4. GRB060219: SARA Observations
  5. GRB 060219: Swift/UVOT Upper Limits
  6. GRB 060219: Swift-XRT Team refined analysis
  7. GRB 051221B: Swift-XRT Team Refined Analysis
  8. GRB 060219: Partial refined analysis of the Swift-BAT burst
  9. GRB060218: Radio Afterglow Discovery
  10. GRB 060219: Swift-XRT position typo correction
  11. GRB 060218: MDM Redshift
  12. GRB 060219: Swift-XRT position
  13. GRB 060218: optical/nIR observations at La Palma
  14. GRB060219: SDSS pre-burst observations
  15. GRB 060219: Swift-BAT detection of a weak burst
  16. Oddball GRB 060218, transient or GRB?
  17. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  18. Brightening of the Optical Counterpart of the Possible GRB 060218
  19. GRB 060218: MDM Observations
  20. GRB 060218: Pre-burst detection of a possible host galaxy
  21. GRB 060218A: ROTSE-III Possible Optical Flare
  22. GRB060218: Swift/XRT refined position of a possible burst
  23. Preliminary refined analysis of the Swift-BAT trigger 191157
  24. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  25. GRB 060211B: Swift/UVOT Upper Limits
  26. GRB060218 : SDSS pre-burst observations
  27. GRB 060218: Swift XRT Position
  28. GRB 060218: Swift-BAT detection of a possible burst
  29. GRB 060213: optical afterglow not confirmed
  30. Swift UVOT observations of GRB060213
  31. GRB 060211B: Skynet Observations
  32. GRB 060213: optical afterglow candidate
  33. GRB060213: Swift XRT observations and possible afterglow candidate
  34. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  35. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  36. GRB060213: MASTER final result
  37. GRB 060211b: WIRO NIR Observations
  38. GRB060213:_MASTER_optical_observation
  39. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  40. Konus-Wind observation of bright hard GRB 060213
  41. GRB 060213: IPN localization
  42. GRB 060210: Radio Observations
  43. GRB 060211a: WIRO NIR Observations
  44. GRB060211B: REM optical and NIR observations
  45. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  46. GRB 060211A: Further refined analysis of the Swift burst
  47. GRB060121: optical observations
  48. GRB060110: optical observations
  49. GRB060105: optical observations
  50. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  51. GRB 060211b: P60 Observations
  52. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  53. GRB 060206: SOAR Detections
  54. GRB 050826: Optical Afterglow and Host Galaxy
  55. GRB 060210: Further refined analysis of the Swift-BAT burst
  56. GRB 060211B: Swift/BAT refined analysis
  57. GRB060210: Swift/UVOT Upper Limits
  58. GRB 060211B: Swift-XRT Team refined analysis
  59. GRB060211b: optical observation
  60. GRB060211B: Swift/XRT position
  61. GRB 060210: Optical Observations
  62. GRB060211.7: MASTER_optical_observation under the snow
  63. GRB 060211A: Swift XRT Team Refined Analysis
  64. GRB 060211B: Swift-BAT detection of a burst
  65. GRB060211: Faulkes North observation
  66. GRB 060211: ROTSE-III Optical Limits
  67. GRB 060211: Swift detection of a long burst
  68. GRB 060210: Refined analysis of the Swift-BAT burst
  69. GRB060210: Swift XRT Refined Analysis
  70. GRB060206, optical observations
  71. GRB 060210 : Xinglong and Lulin optical limit
  72. GRB060210: Optical Observations
  73. GRB060210: Gemini absorption spectroscopy
  74. GRB060210: Early Optical Observations
  75. GRB 060210: optical evolution
  76. GRB060210:Faulkes Telescope North Afterglow Confirmation
  77. GRB 060210: candidate afterglow
  78. GRB 060210: Swift detection of a burst
  79. GRB060210: Optical afterglow
  80. GRB 060206: Swift/UVOT Observations
  81. Swift-BAT trigger 180931 is not a GRB
  82. GRB060209: RTT150 optical observations
  83. GRB 060209 : TAROT optical observation
  84. GRB060209A: MASTER optical observation
  85. GRB 060209(?): Swift-BAT detection of a possible burst
  86. GRB 060206: near-infrared observations (JK' imaging)
  87. GRB 060206: WSRT Radio Observations
  88. GRB 060203: Swift/UVOT upper limits
  89. GRB 060206: TTT Observations
  90. GRB 060206: More PROMPT Detections
  91. GRB 060121 : WIDGET Pre-trigger limit
  92. GRB 060206: Tenagra II Observations
  93. GRB 060206: PROMPT Detections
  94. Retraction of orphan GRB afterglow candidate
  95. GRB060204a: Swift XRT Source is not GRB Afterglow
  96. GRB 060206: optical observations at Asiago
  97. Orphan GRB Afterglow candidate
  98. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  99. GRB 060206: Subaru/FOCAS optical spectroscopy
  100. GRB 060206: IR Detection of the Afterglow

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