The properties of circum-galactic gas in the halo of quasar host galaxies are investigated analyzing Mg II 2800 and C IV 1540 absorption-line systems along the line of sight close to quasars. We used optical spectroscopy of closely aligned pairs of quasars (projected distance ≤ 200 kpc, but at very different redshift) obtained at the VLT and Gran Telescopio Canarias to investigate the distribution of the absorbing gas for a sample of quasars at z∼1. Absorption systems of EW ≥ 0.3 A˚ associated with the foreground quasars are revealed up to 200 kpc from the centre of the host galaxy, showing that the structure of the absorbing gas is patchy with a covering fraction quickly decreasing beyond 100 kpc. In this contribution we use optical and near-IR images obtained at VLT to investigate the relations between the properties of the circum-galactic medium of the host galaxies and of the large scale galaxy environments of the foreground quasars.
@article{arxiv.1712.02619,
title = {Circum-galactic medium in the halo of quasars},
author = {Riccardo Ottolina and Renato Falomo and Aldo Treves and Michela Uslenghi and Jari K. Kotilainen and Riccardo Scarpa and Emanuele P. Farina},
journal= {arXiv preprint arXiv:1712.02619},
year = {2017}
}
Comments
6 pages, 3 figures, proceedings of the conference "QUASARS at all cosmic epochs", accepted for publication on Frontiers in Astronomy and Space Science