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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. GRB060213:_MASTER_optical_observation
  2. GRB060206: Swift XRT observations of an unbroken powerlaw decay
  3. Konus-Wind observation of bright hard GRB 060213
  4. GRB 060213: IPN localization
  5. GRB 060210: Radio Observations
  6. GRB 060211a: WIRO NIR Observations
  7. GRB060211B: REM optical and NIR observations
  8. GRB 060211B: BAT detects no additional burst emission beyond T + 122 sec
  9. GRB 060211A: Further refined analysis of the Swift burst
  10. GRB060121: optical observations
  11. GRB060110: optical observations
  12. GRB060105: optical observations
  13. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  14. GRB 060211b: P60 Observations
  15. GRB 060211A: Partial refined analysis on the Swift-BAT burst
  16. GRB 060206: SOAR Detections
  17. GRB 050826: Optical Afterglow and Host Galaxy
  18. GRB 060210: Further refined analysis of the Swift-BAT burst
  19. GRB 060211B: Swift/BAT refined analysis
  20. GRB060210: Swift/UVOT Upper Limits
  21. GRB 060211B: Swift-XRT Team refined analysis
  22. GRB060211b: optical observation
  23. GRB060211B: Swift/XRT position
  24. GRB 060210: Optical Observations
  25. GRB060211.7: MASTER_optical_observation under the snow
  26. GRB 060211A: Swift XRT Team Refined Analysis
  27. GRB 060211B: Swift-BAT detection of a burst
  28. GRB060211: Faulkes North observation
  29. GRB 060211: ROTSE-III Optical Limits
  30. GRB 060211: Swift detection of a long burst
  31. GRB 060210: Refined analysis of the Swift-BAT burst
  32. GRB060210: Swift XRT Refined Analysis
  33. GRB060206, optical observations
  34. GRB 060210 : Xinglong and Lulin optical limit
  35. GRB060210: Optical Observations
  36. GRB060210: Gemini absorption spectroscopy
  37. GRB060210: Early Optical Observations
  38. GRB 060210: optical evolution
  39. GRB060210:Faulkes Telescope North Afterglow Confirmation
  40. GRB 060210: candidate afterglow
  41. GRB 060210: Swift detection of a burst
  42. GRB060210: Optical afterglow
  43. GRB 060206: Swift/UVOT Observations
  44. Swift-BAT trigger 180931 is not a GRB
  45. GRB060209: RTT150 optical observations
  46. GRB 060209 : TAROT optical observation
  47. GRB060209A: MASTER optical observation
  48. GRB 060209(?): Swift-BAT detection of a possible burst
  49. GRB 060206: near-infrared observations (JK' imaging)
  50. GRB 060206: WSRT Radio Observations
  51. GRB 060203: Swift/UVOT upper limits
  52. GRB 060206: TTT Observations
  53. GRB 060206: More PROMPT Detections
  54. GRB 060121 : WIDGET Pre-trigger limit
  55. GRB 060206: Tenagra II Observations
  56. GRB 060206: PROMPT Detections
  57. Retraction of orphan GRB afterglow candidate
  58. GRB060204a: Swift XRT Source is not GRB Afterglow
  59. GRB 060206: optical observations at Asiago
  60. Orphan GRB Afterglow candidate
  61. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  62. GRB 060206: Subaru/FOCAS optical spectroscopy
  63. GRB 060206: IR Detection of the Afterglow
  64. GRB 060206: Lick 3m Spectroscopy
  65. GRB 060204A: ROSAT Pointing
  66. GRB 060206: Super-LOTIS observations
  67. GRB060204A: Swift/UVOT observations
  68. GRB 060206: Swift-BAT refined analysis
  69. GRB 060206 : Lulin optical observations
  70. GRB060206: SDSS Pre-Burst Observations
  71. GRB060206: Swift XRT Refined Analysis
  72. GRB060206: Liverpool Telescope observation
  73. GRB 060206: Spectroscopic Redshift
  74. GRB060206: P60 Optical Observations
  75. GRB 060206: KAIT observations
  76. GRB060206: Swift XRT Position
  77. GRB060206: SARA Detection
  78. GRB 060206: RAPTOR observations of afterglow candidate variability.
  79. GRB 060206: High redshift burst
  80. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  81. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  82. GRB060206: Optical afterglow
  83. GRB060206: Swift-BAT detection of a burst
  84. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  85. GRB060203: WHT Z-band observations
  86. BAT GRB 060204C is probably not a GRB
  87. GRB060204C: optical observation
  88. GRB 060204B: BVRi-band detections of optical afterglow
  89. GRB 060204A: Swift XRT upper limit
  90. GRB 060204A: FRAM optical observations
  91. GRB060204B: Swift/UVOT refined analysis
  92. GRB 060204C: optical observations
  93. Swift XRT Observation of GRB 060204C
  94. GRB 060204B: Swift-BAT refined analysis
  95. GRB 060204B: ART early limit
  96. GRB060204B: Swift XRT Team Refined Analysis
  97. GRB 060204C: OSN limits
  98. GRB 060204b: Keck/LRIS Afterglow Confirmation
  99. GRB 060204C: BOOTES-IR optical limits
  100. GRB 060204C: Liverpool Telescopes optical limit

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