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

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