The one-dimensional power spectrum from the SDSS DR14 Ly$\alpha$ forests
  We present a measurement of the 1D Ly$\alpha$ forest flux power spectrum,
using the complete Baryon Oscillation Spectroscopic Survey (BOSS) and first
extended-BOSS (eBOSS) quasars at $z_{\rm qso}>2.1$, corresponding to the
fourteenth data release (DR14) of the Sloan Digital Sky Survey (SDSS). Our
results cover thirteen bins in redshift from $z_{\rm Ly\alpha}=2.2$ to 4.6, and
scales up to $k=0.02\rm \,(km/s)^{-1}$. From a parent sample of 180,413
visually inspected spectra, we selected the 43,751 quasars with the best
quality; this data set improves the previous result from the ninth data release
(DR9), both in statistical precision (achieving a reduction by a factor of two)
and in redshift coverage. We also present a thorough investigation of
identified sources of systematic uncertainties that affect the measurement. The
resulting 1D power spectrum of this work is in excellent agreement with the one
from the BOSS DR9 data.
