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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"

35259 results found.

  1. GRB 050925 : I-band observation at Xinglong observatory
  2. GRB050925: Faulkes Telescope North R-band limit
  3. GRB050925: Swift-BAT detection of a short burst
  4. GRB 050922B: Correction to BAT refined analysis, longer burst
  5. GRB050922C: TNG spectroscopic observations
  6. GRB050922B: refined XRT analysis
  7. Konus-Wind observation of GRB 050922C
  8. GRB 050922C: Refined redshift
  9. GRB OT observation
  10. GRB050922C: observation at MonteBoo
  11. INT 2.5m limit for GRB050922B
  12. GRB 050922B: optical limit
  13. GRB050922C: Optical Observations
  14. GRB 050922C: Swift XRT refined analysis
  15. HETE Fregate observations of GRB 050922C
  16. GRB 050922C: Swift-BAT refined analysis
  17. GRB 050922B: Swift-BAT refined analysis
  18. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  19. GRB 050922C: optical obserations
  20. GRB 050922C: NOT optical observations
  21. GRB 050922A: Analysis of Swift/XRT TOO observation
  22. GRB 050922C: Swift detection of a bright burst
  23. GRB 050922C: ROTSE-IIId Refined Analysis
  24. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  25. GRB 050922B: ROTSE-III Optical Limits
  26. GRB 050922B,optical observation
  27. GRB050922B: Swift-BAT detection of a weak long burst
  28. Possible GRB 050922 detected by INTEGRAL
  29. GRB050820B: analysis of the XMM-Newton observation
  30. GRB050916: Swift/UVOT Upper Limits
  31. GRB 050916: Swift-BAT refined analysis
  32. GRB 050918 - A long GRB detected by INTEGRAL
  33. GRB 050915a: Radio Observations
  34. Swift-BAT trigger 155764 is not a GRB
  35. Swift-BAT trigger 155764 is probably not a GRB
  36. Swift-BAT trigger 155535 is definitely not a GRB
  37. GRB 050916: XRT position
  38. GRB 050915b, SMARTS optical/IR observations of the XRT position
  39. GRB 050915B: Swift-BAT refined analysis
  40. GRB 050915B: Swift/UVOT Upper Limits
  41. GRB 050915a: IR Transient
  42. GRB 050915B: XRT position
  43. GRB 050915b, SMARTS optical/IR observations
  44. GRB 050915: KAIT optical limit
  45. GRB 050915: IR Observations
  46. GRB 050915: Swift XRT refined analysis
  47. GRB 050915: Swift-BAT refined analysis
  48. GRB050915: P60 Optical Observations
  49. GRB 050915: ROTSE-III optical limits
  50. GRB 050915: Swift detection of a GRB
  51. GRB050911: Upper limit on X-ray afterglow
  52. Swift-BAT trigger 155072 ground analysis
  53. Swift-BAT trigger 155072 is probably not a GRB
  54. GRB 050911: LCO limits on a variable source
  55. GRB 050908: DEIMOS spectrum and further analysis
  56. Swift is in normal operation
  57. GRB 050911, optical content of Swift/XRT error box
  58. GRB 050911: LCO observations
  59. GRB 050911, optical observations
  60. GRB 050911: Swift-BAT refined analysis
  61. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  62. GRB 050911: z~0.16 cluster in the field
  63. GRB 050910a: TAROT early optical limits
  64. RBO GRB 050908 observations
  65. WIRO observations in I of GRB 050908
  66. GRB 050906: Possible X-ray Counterpart
  67. GRB 050906: RTT150 optical observations
  68. GRB050908: VLT R-band decay index.
  69. GRB 050908: Swift-BAT refined analysis
  70. GRB 050908: Optical observations
  71. Gemini Spectroscopy of GRB 050908
  72. GRB 050908: spectroscopic redshift
  73. GRB 050908: Prompt PROMPT Observations
  74. GRB 050908 : Swift XRT position
  75. GRB 050908: KAIT observations
  76. GRB 050908: P60 Confirmation of Optical Afterglow
  77. GRB 050908: Optical Observations
  78. GRB 050908: Swift detection of a burst
  79. Swift trigger 154073 is not a GRB
  80. GRB 050906: Optical observations at the Very Large Telescope
  81. GRB050904: CrAO optical observations
  82. GRB 050904 BAT refined analysis of complete data set
  83. GRB 050904: Subaru Optical Spectroscopy
  84. GRB 050906: MARGE Optical Limits
  85. GRB 050906: Swift-BAT refined analysis
  86. GRB 050906: Swift XRT upper limit
  87. GRB 050906: Radio Observations
  88. GRB 050904: Keck I-band Imaging
  89. GRB 050904: more VLT NIR observations
  90. GRB 050904: BOOTES early R-band observation
  91. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  92. GRB 050906: Bright galaxy in BAT error box
  93. GRB 050906: Swift/BAT Detection of a possible burst
  94. GRB 050904: More SOAR
  95. GRB 050904: photometric redshift
  96. GRB 050904: Swift/UVOT observations
  97. GRB 050904: Afterglow Astrometry
  98. GRB 050904: NIR object inside the XRT error box
  99. GRB 050904: early Swift XRT analysis results
  100. GRB 050904: SOAR YJ and PROMPT Ic Observations

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