科研之友
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摘要
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 z(em) > 2.4. This yields a sample of 21,963 appropriate quasars to search for narrow C IV lambda lambda 1548, 1551 absorptions with W-r >= 0.2 angstrom 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 C IV absorption systems whose absorption redshifts cover a range of z(abs) = 1.8784-4.3704. In this paper and Paper I, we have selected 37,241 appropriate quasars with median S/N >= 4 and 1.54 less than or similar to z(em) less than or similar to 5.16 to visually analyze narrow C IV lambda lambda 1548, 1551 absorption doublets one by one. Atotal of 15,999 quasars are found to have at least one appropriate absorption system imprinted on their spectra. From these 15,999 quasar spetra, we have detected 23,336 appropriate C IV lambda lambda 1548, 1551 absorption systems with W-r >= 0.2 angstrom whose absorption redshifts cover a range of z(abs) = 1.4544-4.3704. The largest values of W-r are 3.19 angstrom for the lambda 1548 absorption line and 2.93 angstrom for the lambda 1551 absorption line, respectively. We find that only a few absorbers show large values of W-r. About 1.1% of the total absorbers have W-r lambda 1548 >= 2.0 angstrom.
