abstract.tex

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\begin{abstract}

\emph{Goals}: We present a new and improved catalog of Thorium and Argon (ThAr) lines across the breadth of the visible, near infrared, and near ultraviolet spectrum to allow wider-range calibrated spectra, the tighter characterization of EXPRES spectra and more precise measurements of radial velocity (RV). We base this catalog on a subset of the National Institute of Standards and Technologies (NIST) ThAr Line List  which extends from 3500 – 8500 \AA. We present corrections to these lines specific to the EXtreme PREcision Spectrograph (EXPRES) based on spectra of a laser frequency comb (LFC) produced through EXPRES. The wavelength range of the corrections extends from 4570 - 7230 \AA.

\emph{Methods}: We use a series of 701 ThAr spectra taken throughout 2019 and collect a total of 4142 LFC spectra taken within $\pm $30 minutes of each ThAr exposure (with a median of 5 LFC exposures per ThAr exposure) and the collective LFCs are fit with a smooth spline to assign a new wavelength to each ThAr line’s central pixel.

\emph{Results}: We update 2383 ThAr lines of the catalog with values assigned by the LFC wavelength solution. These corrections are confined to the maximum 2019 wavelength range of the LFC output, yet this represents a significant increase in wavelength range compared to the current LFC limit (with an additional 356 \AA on the blue end). The updated catalog values have order-of-magnitude uncertainties of $10^{-4}$ \AA \ and produce \textbf{FILLER} results within EXPRES’ calibration pipeline.

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\end{abstract}