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 ($83{{\ \rm per\ cent}}$) 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 $d\mathcal {N}/dX = 5.1\pm 1.0$ for $\log [N(\rm {C}\, \small {{IV}})~(\rm {cm}^{-2})]\ge 12.9$, and $\Omega _{\rm {C}\, \small {{IV}}}=(8.01\pm 1.62) \times 10^{-8}$ for $12.9 \le \log [N(\rm {C}\, \small {{IV}})~(\rm {cm}^{-2})] \le 15.0$. The C iv bearing diffuse gas in the z < 0.16 Universe has a metallicity of (2.07  ±  0.43)  ×  10−3 Z⊙, an order of magnitude more than the metal abundances in the IGM at high redshifts (z ≳ 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⋆.

We present analysis of the galaxy environment and physical properties of a partial Lyman limit system at 𝑧 = 0.83718 with H and metal line components closely separated in redshift space (|Δ𝑣| ≈ 400 km s −1 ) towards the background quasar HE 1003+0149. The 𝐻𝑆𝑇/COS farultraviolet spectrum provides coverage of lines of oxygen ions from O to O . Comparison of observed spectral lines with synthetic profiles generated from Bayesian ionization modeling reveals the presence of two distinct gas phases in the absorbing medium. The low-ionization phase of the absorber has sub-solar metallicities (∼ 1/10 solar) with indications of [C/O] < 0 in each of three components. The O and O trace a more diffuse higher-ionization medium with predicted H column densities that are ≈ 2 dex lower. The quasar field observed with 𝑉 𝐿𝑇/MUSE reveals three dwarf galaxies with stellar masses of 𝑀 * ∼ 10 8 − 10 9 M , and with star formation rates of ≈ 0.5 − 1 M yr −1 , at projected separations of 𝜌/𝑅 vir ≈ 1.8 − 3.0 from the absorber. Over a wider field with projected proper separation of ≤ 5 Mpc and radial velocity offset of |Δ𝑣| ≤ 1000 km s −1 from the absorber, 21 more galaxies are identified in the 𝑉 𝐿𝑇/VIMOS and Magellan deep galaxy redshift surveys, with 8 of them within 1 Mpc and 500 km s −1 , consistent with the line of sight penetrating a group of galaxies. The absorber presumably traces multiple phases of cool (𝑇 ∼ 10 4 K) photoionized intragroup medium. The inferred [C/O] < 0 hint at preferential enrichment from core-collapse supernovae, with such gas displaced from one or more of the nearby galaxies, and confined to the group medium.

No abstract