Absorption systems at z∼ 2 as a probe of the circumgalactic medium: a probabilistic approach. Issue 3 (18th May 2018)

• Record Type: Journal Article
• Authors: Mongardi, C; Viel, M; D'Odorico, V; Kim, T-S; Barai, P; Murante, G; Monaco, P
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 478:Issue 3(2018)
• Page Start: 3266
• Page End: 3289
• Publication Date: 2018-05-18
• Subjects: method: numerical -- intergalactic medium -- quasars: absorption lines; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty1283
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We characterize the properties of the intergalactic medium (IGM) around a sample of galaxies extracted from state-of-the-art hydrodynamical simulations of structure formation in a cosmological volume of 25 Mpc comoving at z ∼ 2. The simulations are based on two different subresolution schemes for star formation and supernova feedback: the Multi-Phase Particle Integrator (MUPPI) scheme and the Effective Model. We develop a quantitative and probabilistic analysis based on the apparent optical depth method of the properties of the absorbers as a function of impact parameter from their nearby galaxies: in such a way, we probe different environments from circumgalactic medium to low-density filaments. Absorbers' properties are then compared with a spectroscopic observational data set obtained from high-resolution quasar spectra. Our main focus is on the $N_{\rm C\, \small {IV}}$ –$N_{\rm H\, \small {I}}$ relation around simulated galaxies: the results obtained with MUPPI and the Effective model are remarkably similar, with small differences only confined to regions at impact parameters b = [1 − 3] × r vir . Using $\rm{C\, {\small IV}}$ as a tracer of the metallicity, we obtain evidence that the observed metal absorption systems have the highest probability to be confined in a region of 150–400kpc around galaxies. Near-filament environments have instead metallicities too low to be probed by present-day telescopes, but could be probed by future spectroscopical studies. Finally, we compute $\rm{C \, {\small IV}}$ covering fractions which are in agreement with observational data.