Constraining atmospheric parameters and surface magnetic fields with <tt>ZeeTurbo</tt>: an application to SPIRou spectra

ABSTRACT We report first results on a method aimed at simultaneously characterizing atmospheric parameters and magnetic properties of M dwarfs from high-resolution near-IR spectra recorded with SPIRou in the framework Legacy Survey (SLS). Our analysis relies fitting synthetic computed marcs model atmospheres to selected spectral lines, both sensitive insensitive fields. introduce new code, ZeeTurbo, obtained by including Zeeman effect polarized radiative transfer capabilities Turbospectrum. compute grid ZeeTurbo for different field strengths develop process constrain Teff, log g, $\rm {[M/H]}$, {[\alpha /Fe]}$, average surface flux. In this paper, we present our approach assess its performance using simulations, before applying it six targets observed context SLS, namely AU Mic, EV Lac, AD Leo, CN PM J18482+0741, DS Leo. allows us retrieve good agreement literature, yields fluxes range 2–4 kG typical precision 0.05 kG, literature estimates, consistent saturated dynamo regime which most these stars are.