2021/05/31 by Aditya Manuwal, Anand Narayanan, Purvi Udhwani +4 · 1 citation
Physics and Astronomy · #astro-ph.GA #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stab1556
published as Monthly Notices of the Royal Astronomical Society 505.3 (2021): 3635-3654 · Published in MNRAS. Modified to match the text in the published version. 20 pages, 16 figures, 4 tables. The system plots, measurement tables, and discussions on origins of some individual systems, are available online at MNRAS. The link to the supplementary information is present in this arxiv version
arxiv created 2021/06/24 · arxiv updated 2021/06/25
We present here results from a survey of intervening C IV absorbers at z < 0.16 conducted using 223 sightlines from the Hubble Spectroscopic Legacy Archive. Most systems (83%) out of the total sample of 69 have simple kinematics with 1 or 2 C IV components. In the 22 C IV systems with well constrained H I column densities, the temperatures from the b-values imply predominantly photoionized plasma (T≤ 105 K) and non-thermal dynamics. These systems also have solar or higher metallicities. We obtain a C IV line density of dN/dX = 5.1± 1.0 for log [N(C~IV)~(cm-2)]≥12.9, and ΩC~IV=(8.01± 1.62) × 10-8 for 12.9 ≤ log [N(C~IV)~(cm-2)] ≤ 15.0. The C IV bearing diffuse gas in the z < 0.16 Universe has a metallicity of (2.07~±~0.43)~×~10-3 Z\odot, an order of magnitude more than the metal abundances in the IGM at high redshifts (z \gtrsim 5), and consistent with the slow build-up of metals in the diffuse circum/intergalactic space with cosmic time. For z<0.015 (complete above L>0.01L^⋆), the Sloan Digital Sky Survey provides a tentative evidence of declining covering fraction for strong C IV (N>1013.5~cm-2) with ρ (impact parameter) and ρ/Rvir. However, the increase at high separations suggests that strong systems are not necessarily coincident with such galaxies. We also find that strong C IV absorption at z<0.051 is not coincident with galaxy over-dense regions complete for L>0.13L^⋆