论文标题
与紧凑型组相关的复杂多相DLA，在z = 2.431痕迹吸收，流出和潮汐流
A Complex Multiphase DLA Associated with a Compact Group at z=2.431 Traces Accretion, Outflows, and Tidal Streams
论文作者
论文摘要
作为我们识别已知Z = 2-3 MGII吸收器的宿主星系的一部分，使用Keck Cosmic Web Imager（KCWI），我们发现了一个紧凑的组，在Quasar Field J234628 j234628+124859中，Z = 2.431 DLA具有超强MGII吸收。该小组由8-28 kpc内的四个星形星系组成，彼此之间的$ v \ sim40-340 $ km s $^{ - 1} $组成，其中潮汐流在深HST Imaging中却稀疏。组几何中心的d = 25 kpc来自类星体（每个星系的d = 20-40 kpc）。 Galaxy G1 dominates the group ($1.66L_{\ast}$, ${\rm SFR}_{\rm FUV}=11.6$ M$_{\odot}$ yr$^{-1}$) while G2, G3, and G4 are less massive ($0.1-0.3L_{\ast}$, $ {\ rm sfr} _ {\ rm fuv} = 1.4-2.0 $ m $ _ {\ odot} $ yr $^{ - 1} $）。使用VLT/Uves Quasar频谱涵盖HI Lyman系列和金属线（例如MGII，SIIII和CIV），我们表征了沿着视线的运动结构和物理条件，并具有云层的多面数贝叶斯建模。吸收系统的总$ \ log（n（hi）/{\ rm cm}^{ - 2}）= 20.53 $和$ n（hi）$ - 加权平均金属性的$ \ log（z/z _ {\ odot}）= -0.68 $，带有非常大的mgii $ km km km km km s $^{ - 1} $。高度运动复杂的配置文件良好，在低和中间电离阶段的30个云中，具有$ {13 \ lysSim \ log（n（hi）/{\ rm cm}^{ - 2} { - 2} { - 2}）\ simsim20} $和$ -3 \ simsim \ log log（z/z/z/z/z _ \ oc）。将这些特性与星系性质进行比较，我们推断出广泛的气态环境，包括金属富含金属的流出，金属贫困的IgM积聚和来自Galaxy-Galaxy相互作用的潮流。在峰星形成活性时期，这种结构的多样性在复杂的紧凑型组环境周围形成了群体内培养基。低红移紧凑型组的调查将受益于获得这种媒介的更完整的人口普查来表征进化途径。
As part of our program to identify host galaxies of known z=2-3 MgII absorbers with the Keck Cosmic Web Imager (KCWI), we discovered a compact group giving rise to a z=2.431 DLA with ultra-strong MgII absorption in quasar field J234628+124859. The group consists of four star-forming galaxies within 8-28 kpc and $v\sim40-340$ km s$^{-1}$ of each other, where tidal streams are weakly visible in deep HST imaging. The group geometric centre is D=25 kpc from the quasar (D=20-40 kpc for each galaxy). Galaxy G1 dominates the group ($1.66L_{\ast}$, ${\rm SFR}_{\rm FUV}=11.6$ M$_{\odot}$ yr$^{-1}$) while G2, G3, and G4 are less massive ($0.1-0.3L_{\ast}$, ${\rm SFR}_{\rm FUV}=1.4-2.0$ M$_{\odot}$ yr$^{-1}$). Using a VLT/UVES quasar spectrum covering the HI Lyman series and metal lines such as MgII, SiIII, and CIV, we characterised the kinematic structure and physical conditions along the line-of-sight with cloud-by-cloud multiphase Bayesian modelling. The absorption system has a total $\log(N(HI)/{\rm cm}^{-2})=20.53$ and an $N(HI)$-weighted mean metallicity of $\log(Z/Z_{\odot})=-0.68$, with a very large MgII linewidth of $Δv\sim700$ km s$^{-1}$. The highly kinematically complex profile is well-modelled with 30 clouds across low and intermediate ionisation phases with values ${13\lesssim\log(N(HI)/{\rm cm}^{-2})\lesssim20}$ and $-3\lesssim\log(Z/Z_{\odot})\lesssim1$. Comparing these properties to the galaxy properties, we infer a wide range of gaseous environments, including metal-rich outflows, metal-poor IGM accretion, and tidal streams from galaxy--galaxy interactions. This diversity of structures forms the intragroup medium around a complex compact group environment at the epoch of peak star formation activity. Surveys of low redshift compact groups would benefit from obtaining a more complete census of this medium for characterising evolutionary pathways.
