A New Precision Measurement of the Small-Scale Line-of-Sight Power Spectrum of the Ly${\alpha}$ Forest
Michael Walther, Joseph F. Hennawi, Hector Hiss, Jose O\~norbe,, Khee-Gan Lee, Alberto Rorai, and John O'Meara

TL;DR
This paper presents a highly precise measurement of the small-scale Lyα forest power spectrum at redshifts 1.8 to 3.4, utilizing high-resolution spectra and advanced modeling to improve constraints on the intergalactic medium and cosmology.
Contribution
It introduces a novel pipeline and Bayesian framework for accurate power spectrum measurement, accounting for noise, resolution, and metal contamination, extending previous analyses to smaller scales.
Findings
Achieved unprecedented precision on small-scale modes ($k > 0.02$ s/km)
Quantified and mitigated metal line contamination effects
Provided a combined dataset with BOSS for enhanced cosmological constraints
Abstract
We present a new measurement of the Ly forest power spectrum at using 74 Keck/HIRES and VLT/UVES high-resolution, high-S/N quasar spectra. We developed a custom pipeline to measure the power spectrum and its uncertainty, which fully accounts for finite resolution and noise, and corrects for the bias induced by masking missing data, DLAs, and metal absorption lines. Our measurement results in unprecedented precision on the small-scale modes , unaccessible to previous SDSS/BOSS analyses. It is well known that these high- modes are highly sensitive to the thermal state of the intergalactic medium, however contamination by narrow metal lines is a significant concern. We quantify the effect of metals on the small-scale power, and find a modest effect on modes with . As a result, by masking metals and…
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