The Gaia FGK Benchmark Stars - High resolution spectral library
  Context. An increasing number of high resolution stellar spectra is available
today thanks to many past and ongoing spectroscopic surveys. Consequently,
numerous methods have been developed in order to perform an automatic spectral
analysis on a massive amount of data. When reviewing published results, biases
arise and they need to be addressed and minimized.
  Aims. We are providing a homogeneous library with a common set of calibration
stars (known as the Gaia FGK Benchmark Stars) that will allow to assess stellar
analysis methods and calibrate spectroscopic surveys.
  Methods. High resolution and signal-to-noise spectra were compiled from
different instruments. We developed an automatic process in order to homogenize
the observed data and assess the quality of the resulting library.
  Results. We built a high quality library that will facilitate the assessment
of spectral analyses and the calibration of present and future spectroscopic
surveys. The automation of the process minimizes the human subjectivity and
ensures reproducibility. Additionally, it allows us to quickly adapt the
library to specific needs that can arise from future spectroscopic analyses.
