Data Analysis for Precision Spectroscopy: the ESPRESSO Case

Abstract

Astronomical Spectroscopy is rapidly evolving into a precision science, with several science cases increasingly relying on long-term instrumental stability and centimeter-per-second accuracy in wavelength calibration. These requirements strongly call for integrated software tools to manage not only the reduction of data, but also the scientific analysis. The ultra-stable, high-resolution echelle spectrograph ESPRESSO, currently under integration for the ESO Very Large Telescope (first light: 2017) is the first instrument of its kind to include a dedicated Data Analysis Software among its deliverables, to process both stellar and quasar spectra. This software will extract physical information from the reduced data on the fly (e.g., stellar radial velocities, or characterisation of the absorption systems along the sightline to quasars) and will allow interaction through a configurable graphical user interface. In this article we present the features of the ESPRESSO Data Analysis Software and its development status at the first complete internal release. A particular attention is devoted to the algorithms developed for quasar spectral analysis (continuum determination and interpretation of the absorption systems).