<tt>NEIDSpecMatch</tt>: Stellar Parameter Estimation with NEID Spectra Using an Empirical Library

Abstract We introduce NEIDSpecMatch , a tool developed to extract stellar parameters from spectra obtained with the NEID spectrograph. NEIDSpecMatch is based on SpecMatch-Emp and HPFSpecMatch , which estimate stellar parameters by comparing the observed spectrum to well-characterized library spectra. This approach has proven effective for M dwarfs. Utilizing a library of 78 stellar spectra covering effective temperatures from 3000–6000 K, NEIDSpecMatch derives key parameters, including effective temperature, metallicity, surface gravity, and projected rotational velocity. Cross-validation shows median uncertainties of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">eff</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>115</mml:mn> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">K</mml:mi> </mml:math> , σ [Fe/H] = 0.143, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>log</mml:mi> <mml:mi>g</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0.073</mml:mn> </mml:math> across 49 orders. We showcase its application by fitting the spectrum of an M-dwarf and discuss its utility across a wide range of spectra observed with NEID. NEIDSpecMatch is pip -installable.