DAOSPEC: an automatic code for measuring equivalent widths in high-resolution stellar spectra

TL;DR

DAOSPEC is an automated Fortran program designed to measure equivalent widths in high-resolution stellar spectra efficiently, reducing human intervention and improving consistency in spectral analysis.

Contribution

It introduces a novel automated method for measuring spectral line equivalent widths, with detailed analysis of its principles, capabilities, limitations, and comparisons to existing techniques.

Findings

Effective in high-resolution, high S/N spectra

Handles line crowding and continuum placement issues

Shows comparable or improved performance over existing codes

Abstract

DAOSPEC is a Fortran code for measuring equivalent widths of absorption lines in stellar spectra with minimal human involvement. It works with standard FITS format files and it is designed for use with high resolution (R>15000) and high signal-to-noise-ratio (S/N>30) spectra that have been binned on a linear wavelength scale. First, we review the analysis procedures that are usually employed in the literature. Next, we discuss the principles underlying DAOSPEC and point out similarities and differences with respect to conventional measurement techniques. Then experiments with artificial and real spectra are discussed to illustrate the capabilities and limitations of DAOSPEC, with special attention given to the issues of continuum placement; radial velocities; and the effects of strong lines and line crowding. Finally, quantitative comparisons with other codes and with results from the literature are also presented.