论文标题
从$ z = 0.4 $的大量椭圆形中发现多相气体的延迟反馈证据
Evidence for Late-Time Feedback from the Discovery of Multiphase Gas in a Massive Elliptical at $z=0.4$
论文作者
论文摘要
我们报告了超过$ z \大约0 $的静态星系中多相气体的首次检测。这些观察结果使用了更明亮的镜头QSO 0047 $ - $ 1756的图像来探测巨大的ISM（$ m _ {\ rm star} \大约10^{11} \ mathrm {m_ mathrm {m_ \ odot} $）椭圆形的椭圆形镜头银色的eLcim z_ \ mathrmmmmmmmmmmmmmmm {gall}。使用Hubble Space望远镜的宇宙起源光谱仪（COS），我们获得了镜头QSO的中分辨率FUV频谱，并在投影距离$ d = 4.6 $ kpc的镜头ISM中从镜头ISM中识别$ \ mathrm {H_2} $的众多吸收功能。 $ \ mathrm {h_2} $列密度为$ \ log n（\ mathrm {h_2}）/\ mathrm {cm^{ - 2}} = 17.8^{+0.1} _ { - 0.3} $，带有$ f _ $ f _ mathrmmmatrly $ f _ mathrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm {hhogrogy mathrmmmmmmmmmm {h HONGRM {HOLONG MANOLLM {HOLONGY cOLLING局部静止星系。新的COS频谱还揭示了具有高度离子化的物种O VI和N V的运动学复杂的吸收特征，并具有圆柱密度log $ n（\ Mathrm {o vi}）/\ Mathrm {Cm^{ - 2}} = 15.2 v}）/\ mathrm {cm^{ - 2}} = 14.6 \ pm0.1 $，是外部星系中最高的。假设高电离吸收特征起源于短暂的温暖（$ t \ sim10^5 \，$ k）阶段，经受了围绕银河系的热光晕进行辐射冷却的阶段，我们推断出$ \ sim 0.5-1.5 \ \ sim 0.5-1.5 \，\ mathrm {m_ \ odot {m_ \ odot \ odot \ odot \ odot \，yr，yr，yr^{-1}镜头中缺乏恒星形成表明该流的大部分返回到热光晕，这意味着$ \ sim10^{48} \，\ Mathrm {erg {erg \，yr^{ - 1}} $的加热速率。即使在没有活性核的强烈反馈的情况下，即使没有有效的反馈，也足以防止ISM中大量的冷气积聚，从而可以防止大量的冷气积聚。
We report the first detection of multiphase gas within a quiescent galaxy beyond $z\approx0$. The observations use the brighter image of doubly lensed QSO HE 0047$-$1756 to probe the ISM of the massive ($M_{\rm star}\approx 10^{11} \mathrm{M_\odot}$) elliptical lens galaxy at $z_\mathrm{gal}=0.408$. Using Hubble Space Telescope's Cosmic Origins Spectrograph (COS), we obtain a medium-resolution FUV spectrum of the lensed QSO and identify numerous absorption features from $\mathrm{H_2}$ in the lens ISM at projected distance $d=4.6$ kpc. The $\mathrm{H_2}$ column density is $\log N(\mathrm{H_2})/\mathrm{cm^{-2}}=17.8^{+0.1}_{-0.3}$ with a molecular gas fraction of $f_\mathrm{H_2}=2-5\%$, roughly consistent with some local quiescent galaxies. The new COS spectrum also reveals kinematically complex absorption features from highly ionized species O VI and N V with column densities log $N(\mathrm{O VI})/\mathrm{cm^{-2}} =15.2\pm0.1$ and log $N(\mathrm{N V})/\mathrm{cm^{-2}} =14.6\pm0.1$, among the highest known in external galaxies. Assuming the high-ionization absorption features originate in a transient warm ($T\sim10^5\,$K) phase undergoing radiative cooling from a hot halo surrounding the galaxy, we infer a mass accretion rate of $\sim 0.5-1.5\,\mathrm{M_\odot\,yr^{-1}}$. The lack of star formation in the lens suggests the bulk of this flow is returned to the hot halo, implying a heating rate of $\sim10^{48}\,\mathrm{erg\,yr^{-1}}$. Continuous heating from evolved stellar populations (primarily SNe Ia but also winds from AGB stars) may suffice to prevent a large accumulation of cold gas in the ISM, even in the absence of strong feedback from an active nucleus.
