In this work, we study argon abundances in the interstellar medium of high-redshift galaxies (2<z(abs)<4.2) detected as Damped Lya absorbers (DLA) in the spectra of background quasars. We use high-resolution quasar spectra obtained from the ESO-UVES advanced data products (EUADP) database. We present 3 new measurements and 5 upper limits of ArI. We further compiled DLAs/sub-DLA data from the literature with measurements available of argon and alpha-capture elements (S or Si), making up a total of 37 systems, i.e. the largest DLA argon sample investigated so far. We confirm that argon is generally deficient in DLAs, with a mean value [Ar/alpha]= -0.4+/-0.06dex (standard error of the mean). The [Ar/alpha] ratios show a weak, positive trend with increasing NHI and increasing absorption redshift, and a weak, negative trend with dust-free metallicity, [S/H]. Detailed analysis of the abundance ratios indicates that ArI ionisation, rather than dust depletion or nucleosynthetic evolution, is responsible for the argon deficiency. Altogether, the observational evidence is consistent with a scenario of argon ionisation dominated by quasar metagalactic radiation modulated by local HI self-shielding inside the DLA host galaxies. Our measurements and limits of argon abundances suggest that the cosmic reionisation of HeII is completed above z=3, but more measurements at z(abs)>3.5 are required to probe the final stages of this process of cosmic reionisation.
VLT/UVES observations of extremely strong intervening damped Lyman-alpha systems: Molecular hydrogen and excited carbon, oxygen and silicon at log N(HI)=22.4
Physical conditions in diffuse interstellar medium of local and high redshift galaxies: measurements based on excitation of H$_2$ rotational and CI fine-structure levels
A Complex Multiphase DLA Associated with a Compact Group at z=2.431 Traces Accretion, Outflows, and Tidal Streams
作为我们的计划的一部分，以确定主机星系已知z=2-3 MgII吸收与凯克宇宙网络成像仪（KCWI），我们发现了一个紧凑的组产生一个z=2.431 DLA与超强MgII吸收类星体场J234628+124859。该星系群由四个恒星形成星系组成，它们之间的距离在8-28 kpc之间，$v\sim40-340$和$^{-1}$之间的距离为$v\sim40-340$ km s，在深HST成像中潮汐流很弱。群几何中心距离类星体D=25 kpc（每个星系D=20-40 kpc）。星系G1在这一星系群中占主导地位（$1.66L_{\ast}$，${\rm SFR}_{\rm FUV}=11.6$ M $_{\odot}$ yr $^{-1}$），而G2，G3和G4的质量较小（$0.1-0.3L_{\ast}$，${\rm SFR}_{\rm FUV}=1.4-2.0$ M $_{\odot}$ yr $^{-1}$）。使用VLT/UVES类星体光谱覆盖HI莱曼系列和金属线，如镁II，硅III，和CIV，我们的特点是沿视线的运动结构和物理条件与云的云多相贝叶斯建模。吸收系统具有总$\log(N(HI)/{\rm cm}^{-2})=20.53$和$N(HI)$加权平均金属丰度$\log(Z/Z_{\odot})=-0.68$，具有非常大的MgII线宽$Δv\sim700$ km s $^{-1}$。…
Sharpening quasar absorption lines with ESPRESSO: Temperature of warm gas at $z\sim2$, constraints on the Mg isotopic ratio, and structure of cold gas at $z\sim0.5$
