Catalog of narrow $C~IV$ absorption lines in BOSS (I): for quasars with
  $z_{em} \leq 2.4$
  We have assembled absorption systems by visually identifying
$C~IV\lambda\lambda1548,1551$ absorption doublets in the quasar spectra of the
Baryon Oscillation Spectroscopic Survey (BOSS) one by one. This paper is the
first of the series work. In this paper, we concern quasars with relatively low
redshifts and high signal-to-noise ratios for their spectra, and hence we limit
our analysis on quasars with $z_{em}\le2.4$ and on the doublets with
$W_r\lambda1548\ge0.2$ \AA. Out of the more than 87,000 quasars in the Data
Release 9, we limit our search to 10,121 quasars that have the appropriate
redshifts and spectra with high enough signal-to-noise ratios to identify
narrow C IV absorption lines. Among them, 5,442 quasars are detected to have at
least one $C~IV\lambda\lambda1548,1551$ absorption doublet. We obtain a catalog
containing 8,368 $C~IV\lambda\lambda1548,1551$ absorption systems, whose
redshifts are within $z_{abs}=1.4544$ - $2.2805$. In this catalog, about
$33.7\%$ absorbers have $0.2$ \AA$\le W_r\lambda1548<0.5$ \AA, about $45.9\%$
absorbers have $0.5$ \AA$\le W_r\lambda1548<1.0$ \AA, about $19.2\%$ absorbers
have $1.0$ \AA$\le W_r\lambda1548<2.0$ \AA, and about $1.2\%$ absorbers have
$W_r\lambda1548\ge2.0$ \AA.
