Origin of Metals around Galaxies I: Catalogs of Metal-line Absorption Doublets from High-Resolution Quasar Spectra

TL;DR

This paper introduces a new automated method to catalog metal-line doublets in high-resolution quasar spectra, creating the largest such dataset to date for studying the origin of metals in the circumgalactic and intergalactic media.

Contribution

It develops an automatic algorithm for detecting metal-line doublets and provides extensive catalogs of these absorbers across a wide redshift range, enabling future chemical evolution research.

Findings

Largest high-resolution metal-doublet sample to date

Catalogs include weak lines down to a few millangstroms

Coverage of redshifts from 1 to 5

Abstract

We present the first paper of the series Origin of Metals around Galaxies (OMG) aimed to study the origin of the metals observed in the circumgalactic and intergalactic media. In this work we extract and build the catalogs of metal absorbers that will be used in future analyses, and make our results publicly available to the community. We design a fully automatic algorithm to search for absorption metal-line doublets of the species CIV, NV, SiIV and MgII in high-resolution ($R\gtrsim30\,000$) quasar spectra without human intervention, and apply it to the high-resolution and signal-to-noise ratio spectra of 690 quasars, observed with the UVES and HIRES instruments. We obtain $5\,656$ CIV doublets, $7\,919$ doublets of MgII, $2\,258$ of SiIV, and 239 of NV, constituting the largest high-resolution metal-doublet samples to date, and estimate the dependence of their completeness and purity on various doublet parameters such as equivalent width and redshift, using real and artificial quasar spectra. The catalogs include doublets with rest-frame line equivalent widths down to a few ${\rm m\AA}$, all detected at a significance above 3$\sigma$, and covering the redshifts between $1<z \lesssim 5$, properties that make them useful for a wide range of chemical evolution studies.