论文标题
检测代理中高Z星系中的PAH：在极强的阻尼Lyman-Alpha吸收器中对QSO SDSS J1143+1420 Z = 2.323的物理条件进行建模
Detecting PAHs in high-z galaxies in proxy: Modelling physical conditions in an extremely strong damped Lyman-alpha absorber towards QSO SDSS J1143+1420 at z=2.323
论文作者
论文摘要
我们探讨了在高红移时检测到富含气体，吸收式选择的星系中多环芳烃（PAH）的间接方法。我们查看介于QSO SDSS J1143+1420的介于log（n（hi）> 〜21.7）的中间，极强的lyman-alpha吸收器（或ESDLA）的光学VLT/X射击观测值（或eSDLA），Z（esdla）= 2.323。文献研究表明，该ESDLA包含灰尘和弥漫性分子氢的特征，并且由于其紧密的空间接近度（影响参数，RHO = 0.6 +/- 0.3 kpc）与其相关的星系。在有限的视线沿线（IR） - 谱线的有限观察结果中，没有直接检测到PAHS的发射。因此，我们使用多云的数值模拟建模间接探测ESDLA中PAH的存在。我们注意到，在模型中需要包括PAH，以重现观察到的温度H2和CI的柱密度。因此，我们在ESDLA中间接地推断出PAH的存在，其中PAH/H = 10^（ - 7.046）。我们还通过在吸收剂休息框架上通过灰尘对QSO光谱进行建模，我们还相对于星形星系测量了一个低凸起强度（E（bump）〜0.03-0.19 mag）。这与使用多云建模间接获得的低PAH丰度一致。我们的研究强调了多云建模的用法间接检测到高红移气体富含吸收的星系中的PAH。
We explore indirect methods to detect Polycyclic Aromatic Hydrocarbons (PAHs) in gas-rich, absorption-selected galaxies at high redshift. We look at the optical VLT/X-shooter observations of an intervening, extremely strong damped Lyman-alpha absorber (or ESDLA, with log(N(HI))>~21.7)) towards QSO SDSS J1143+1420 at redshift, z(ESDLA)=2.323. Literature studies have shown that this ESDLA contains signatures of dust and diffuse molecular hydrogen and it was specifically chosen for our study due to its close spatial proximity (impact parameter, rho=0.6+/-0.3 kpc) with its associated galaxy. There is no direct detection of PAHs emission in the limited observations of infrared(IR)-spectra along this sight-line. Hence, we use CLOUDY numerical simulation modelling to indirectly probe the presence of PAH in the ESDLA. We note that PAHs need to be included in the models to reproduce the observed column densities of warm H2 and CI. Thus, we infer the presence of PAHs indirectly in our ESDLA, with an abundance of PAH/H = 10^(-7.046). We also measure a low 2175 A bump strength (E(bump)~0.03-0.19 mag) relative to star-forming galaxies by modelling extinction of QSO spectra by dust at the absorber rest-frame. This is consistent with the low PAH abundance obtained indirectly using CLOUDY modelling. Our study highlights the usage of CLOUDY modelling to indirectly detect PAH in high-redshift gas-rich absorption-selected galaxies.
