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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 $C~IVλ\lambda1548,1551$ 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 $W_r\lambda1548\ge0.2$ Å. 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 $C~IVλ\lambda1548,1551$ absorption doublet. We obtain a catalog containing 8,368 $C~IVλ\lambda1548,1551$ absorption systems, whose redshifts are within $z_{abs}=1.4544$ - $2.2805$. In this catalog, about $33.7\%$ absorbers have $0.2$ Å$\le W_r\lambda1548<0.5$ Å, about $45.9\%$ absorbers have $0.5$ Å$\le W_r\lambda1548<1.0$ Å, about $19.2\%$ absorbers have $1.0$ Å$\le W_r\lambda1548<2.0$ Å, and about $1.2\%$ absorbers have $W_r\lambda1548\ge2.0$ Å.