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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: Radio Afterglow Discovery
  2. GRB 060219: Swift-XRT position typo correction
  3. GRB 060218: MDM Redshift
  4. GRB 060219: Swift-XRT position
  5. GRB 060218: optical/nIR observations at La Palma
  6. GRB060219: SDSS pre-burst observations
  7. GRB 060219: Swift-BAT detection of a weak burst
  8. Oddball GRB 060218, transient or GRB?
  9. GRB060218: Swift/XRT Team preliminary analysis of the possible burst
  10. Brightening of the Optical Counterpart of the Possible GRB 060218
  11. GRB 060218: MDM Observations
  12. GRB 060218: Pre-burst detection of a possible host galaxy
  13. GRB 060218A: ROTSE-III Possible Optical Flare
  14. GRB060218: Swift/XRT refined position of a possible burst
  15. Preliminary refined analysis of the Swift-BAT trigger 191157
  16. Further UVOT Observations of the Candidate Optical Afterglow for GRB 060218
  17. GRB 060211B: Swift/UVOT Upper Limits
  18. GRB060218 : SDSS pre-burst observations
  19. GRB 060218: Swift XRT Position
  20. GRB 060218: Swift-BAT detection of a possible burst
  21. GRB 060213: optical afterglow not confirmed
  22. Swift UVOT observations of GRB060213
  23. GRB 060211B: Skynet Observations
  24. GRB 060213: optical afterglow candidate
  25. GRB060213: Swift XRT observations and possible afterglow candidate
  26. GRB 060213: pseudo-z = 3.5 +/- 0.35 from spectral parameters
  27. GRB 060206: Confirmation of Rapid Fading at Optical Wavelengths
  28. GRB060213: MASTER final result
  29. GRB 060211b: WIRO NIR Observations
  30. GRB060213:_MASTER_optical_observation
  31. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  32. Konus-Wind observation of bright hard GRB 060213
  33. GRB 060213: IPN localization
  34. GRB 060210: Radio Observations
  35. GRB 060211a: WIRO NIR Observations
  36. GRB060211B: REM optical and NIR observations
  37. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  38. GRB 060211A: Further refined analysis of the Swift burst
  39. GRB060121: optical observations
  40. GRB060110: optical observations
  41. GRB060105: optical observations
  42. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  43. GRB 060211b: P60 Observations
  44. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  45. GRB 060206: SOAR Detections
  46. GRB 050826: Optical Afterglow and Host Galaxy
  47. GRB 060210: Further refined analysis of the Swift-BAT burst
  48. GRB 060211B: Swift/BAT refined analysis
  49. GRB060210: Swift/UVOT Upper Limits
  50. GRB 060211B: Swift-XRT Team refined analysis
  51. GRB060211b: optical observation
  52. GRB060211B: Swift/XRT position
  53. GRB 060210: Optical Observations
  54. GRB060211.7: MASTER_optical_observation under the snow
  55. GRB 060211A: Swift XRT Team Refined Analysis
  56. GRB 060211B: Swift-BAT detection of a burst
  57. GRB060211: Faulkes North observation
  58. GRB 060211: ROTSE-III Optical Limits
  59. GRB 060211: Swift detection of a long burst
  60. GRB 060210: Refined analysis of the Swift-BAT burst
  61. GRB060210: Swift XRT Refined Analysis
  62. GRB060206, optical observations
  63. GRB 060210 : Xinglong and Lulin optical limit
  64. GRB060210: Optical Observations
  65. GRB060210: Gemini absorption spectroscopy
  66. GRB060210: Early Optical Observations
  67. GRB 060210: optical evolution
  68. GRB060210:Faulkes Telescope North Afterglow Confirmation
  69. GRB 060210: candidate afterglow
  70. GRB 060210: Swift detection of a burst
  71. GRB060210: Optical afterglow
  72. GRB 060206: Swift/UVOT Observations
  73. Swift-BAT trigger 180931 is not a GRB
  74. GRB060209: RTT150 optical observations
  75. GRB 060209 : TAROT optical observation
  76. GRB060209A: MASTER optical observation
  77. GRB 060209(?): Swift-BAT detection of a possible burst
  78. GRB 060206: near-infrared observations (JK' imaging)
  79. GRB 060206: WSRT Radio Observations
  80. GRB 060203: Swift/UVOT upper limits
  81. GRB 060206: TTT Observations
  82. GRB 060206: More PROMPT Detections
  83. GRB 060121 : WIDGET Pre-trigger limit
  84. GRB 060206: Tenagra II Observations
  85. GRB 060206: PROMPT Detections
  86. Retraction of orphan GRB afterglow candidate
  87. GRB060204a: Swift XRT Source is not GRB Afterglow
  88. GRB 060206: optical observations at Asiago
  89. Orphan GRB Afterglow candidate
  90. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  91. GRB 060206: Subaru/FOCAS optical spectroscopy
  92. GRB 060206: IR Detection of the Afterglow
  93. GRB 060206: Lick 3m Spectroscopy
  94. GRB 060204A: ROSAT Pointing
  95. GRB 060206: Super-LOTIS observations
  96. GRB060204A: Swift/UVOT observations
  97. GRB 060206: Swift-BAT refined analysis
  98. GRB 060206 : Lulin optical observations
  99. GRB060206: SDSS Pre-Burst Observations
  100. GRB060206: Swift XRT Refined Analysis

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