Catalog of narrow C IV absorption lines in BOSS (II): for quasars with zem > 2.4

TL;DR

This paper expands the catalog of narrow C IV absorption lines in quasar spectra from BOSS, analyzing over 21,000 quasars with zem > 2.4 to identify and characterize absorption systems, providing a large dataset for studying quasar environments.

Contribution

It presents an expanded catalog of narrow C IV absorption systems in high-redshift quasars, with detailed analysis and visual verification, improving the understanding of absorption features at z > 2.4.

Findings

Detected 23,336 C IV absorption systems in 15,999 quasars.

Found that only about 1.1% of absorbers have Wr >= 2.0 Å.

Absorption redshifts range from 1.4544 to 4.3704.

Abstract

As the second work in a series of papers aiming to detect absorption systems in the quasar spectra of the Baryon Oscillation Spectroscopic Survey, we continue the analysis of Paper I by expanding the quasar sample to those quasars with zem>2.4. This yields a sample of 21,963 appropriate quasars to search for narrow C IV absorptions with Wr>=0.2A for both lines. There are 9708 quasars with at least one appropriate absorption system imprinted on their spectra. From these spectra, we detect 13,919 narrow Civabsorption systems whose absorption redshifts cover a range of zabs=1.8784 - 4.3704. In this paper and Paper 1, we have selected 37,241 appropriate quasars with median SNR>= 4 and 1.54<= zem <=5.16 to visually analyze narrow C IV absorption doublets one by one. A total of 15,999 quasars are found to have at least one appropriate absorption system imprinted on their spectra. From these 15,999 quasar spectra, we have detected 23,336 appropriate C IV absorption systems with Wr>=0.2A whose absorption redshifts cover a range of zabs=1.4544 - 4.3704. The largest values of Wr are 3.19 A for the \lambda1548 absorption line and 2.93 A for the lambda1551 absorption line, respectively. We find that only a few absorbers show large values of Wr. About 1.1% absorbers of the total absorbers have Wr>=2.0 A.