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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. Brightening of the Optical Counterpart of the Possible GRB 060218
  2. GRB 060218: MDM Observations
  3. GRB 060218: Pre-burst detection of a possible host galaxy
  4. GRB 060218A: ROTSE-III Possible Optical Flare
  5. GRB060218: Swift/XRT refined position of a possible burst
  6. Preliminary refined analysis of the Swift-BAT trigger 191157
  7. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  8. GRB 060211B: Swift/UVOT Upper Limits
  9. GRB060218 : SDSS pre-burst observations
  10. GRB 060218: Swift XRT Position
  11. GRB 060218: Swift-BAT detection of a possible burst
  12. GRB 060213: optical afterglow not confirmed
  13. Swift UVOT observations of GRB060213
  14. GRB 060211B: Skynet Observations
  15. GRB 060213: optical afterglow candidate
  16. GRB060213: Swift XRT observations and possible afterglow candidate
  17. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  18. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  19. GRB060213: MASTER final result
  20. GRB 060211b: WIRO NIR Observations
  21. GRB060213:_MASTER_optical_observation
  22. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  23. Konus-Wind observation of bright hard GRB 060213
  24. GRB 060213: IPN localization
  25. GRB 060210: Radio Observations
  26. GRB 060211a: WIRO NIR Observations
  27. GRB060211B: REM optical and NIR observations
  28. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  29. GRB 060211A: Further refined analysis of the Swift burst
  30. GRB060121: optical observations
  31. GRB060110: optical observations
  32. GRB060105: optical observations
  33. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  34. GRB 060211b: P60 Observations
  35. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  36. GRB 060206: SOAR Detections
  37. GRB 050826: Optical Afterglow and Host Galaxy
  38. GRB 060210: Further refined analysis of the Swift-BAT burst
  39. GRB 060211B: Swift/BAT refined analysis
  40. GRB060210: Swift/UVOT Upper Limits
  41. GRB 060211B: Swift-XRT Team refined analysis
  42. GRB060211b: optical observation
  43. GRB060211B: Swift/XRT position
  44. GRB 060210: Optical Observations
  45. GRB060211.7: MASTER_optical_observation under the snow
  46. GRB 060211A: Swift XRT Team Refined Analysis
  47. GRB 060211B: Swift-BAT detection of a burst
  48. GRB060211: Faulkes North observation
  49. GRB 060211: ROTSE-III Optical Limits
  50. GRB 060211: Swift detection of a long burst
  51. GRB 060210: Refined analysis of the Swift-BAT burst
  52. GRB060210: Swift XRT Refined Analysis
  53. GRB060206, optical observations
  54. GRB 060210 : Xinglong and Lulin optical limit
  55. GRB060210: Optical Observations
  56. GRB060210: Gemini absorption spectroscopy
  57. GRB060210: Early Optical Observations
  58. GRB 060210: optical evolution
  59. GRB060210:Faulkes Telescope North Afterglow Confirmation
  60. GRB 060210: candidate afterglow
  61. GRB 060210: Swift detection of a burst
  62. GRB060210: Optical afterglow
  63. GRB 060206: Swift/UVOT Observations
  64. Swift-BAT trigger 180931 is not a GRB
  65. GRB060209: RTT150 optical observations
  66. GRB 060209 : TAROT optical observation
  67. GRB060209A: MASTER optical observation
  68. GRB 060209(?): Swift-BAT detection of a possible burst
  69. GRB 060206: near-infrared observations (JK' imaging)
  70. GRB 060206: WSRT Radio Observations
  71. GRB 060203: Swift/UVOT upper limits
  72. GRB 060206: TTT Observations
  73. GRB 060206: More PROMPT Detections
  74. GRB 060121 : WIDGET Pre-trigger limit
  75. GRB 060206: Tenagra II Observations
  76. GRB 060206: PROMPT Detections
  77. Retraction of orphan GRB afterglow candidate
  78. GRB060204a: Swift XRT Source is not GRB Afterglow
  79. GRB 060206: optical observations at Asiago
  80. Orphan GRB Afterglow candidate
  81. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  82. GRB 060206: Subaru/FOCAS optical spectroscopy
  83. GRB 060206: IR Detection of the Afterglow
  84. GRB 060206: Lick 3m Spectroscopy
  85. GRB 060204A: ROSAT Pointing
  86. GRB 060206: Super-LOTIS observations
  87. GRB060204A: Swift/UVOT observations
  88. GRB 060206: Swift-BAT refined analysis
  89. GRB 060206 : Lulin optical observations
  90. GRB060206: SDSS Pre-Burst Observations
  91. GRB060206: Swift XRT Refined Analysis
  92. GRB060206: Liverpool Telescope observation
  93. GRB 060206: Spectroscopic Redshift
  94. GRB060206: P60 Optical Observations
  95. GRB 060206: KAIT observations
  96. GRB060206: Swift XRT Position
  97. GRB060206: SARA Detection
  98. GRB 060206: RAPTOR observations of afterglow candidate variability.
  99. GRB 060206: High redshift burst
  100. GRB060204a: Swift XRT Detection of an Afterglow Candidate

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