论文标题
由于缺乏海洋阶层培养基引起的绿色山谷中星系淬灭的证据
Evidence for galaxy quenching in the green valley caused by a lack of a circumgalactic medium
论文作者
论文摘要
银河系的性质与其环境培养基（CGM）之间的关系提供了对星系如何发展的独特视图。我们提出一个有趣的边缘（i = 86度）磁盘星系（G1547），其中CGM由背景类星体以84 kpc的距离探测，并且在星系主要轴的10度内。 G1547 does not have any detectable CGM absorption down to stringent limits, covering HI (EW$_r$<0.02A, log(N(HI)/cm$^{-2}$)<12.6) and a range of low and high ionisation absorption lines (OI, CII, NII, SiII, CIII, NIII, SiIII, CIV, SIIV，NV和OVI）。鉴于$ 1.00 _ { - 0.04}^{+0.00} $的覆盖范围为$ 1.00 _ {+0.00} $，对于50-100 kpc quasar sighlines的$ 1.00 _ { - 0.04}^{+0.00} $。 G1547具有低sfr（1.1 m $ _ {\ odot} $ yr $^{ - 1} $），ssfr（$ 1.5 \ times10^{ - 10} $ yr $^{ - 1} $ m $ _ {\ odot} $ yr $^{ - 1} $ kpc $^{ - 2} $），并且不显示AGN或Star-Formation驱动驱动的溢出。与星系的一般人群相比，G1547处于绿谷，具有高于平均水平的金属性，梯度为负。与其他HI吸收选择的星系相比，我们发现具有日志（SSFR/yr $^{ - 1}）<-11 $具有较低的可能性（4/12）的静态星系，其在其CGM中具有可检测到的HI的概率（4/12），而所有星系（40/40）则使用log（40/40），而log（ssfr/yr $ $ $^{-1}我们得出的结论是，SSFR是HI CGM存在的良好指标。但是，有趣的是，G1547是唯一具有LOG（SSFR/yr $^{ - 1}）> -11 $的星系，该星系没有可检测到的CGM。鉴于G1547的特性及其缺乏CGM，由于缺乏燃料来进行恒星形成，G1547正进行淬火，估计Quench的时间表为$ 4 \ pm1 $ gyr。 G1547对外部机制提供了独特的视角，可以解释星系迁移到绿谷中。
The relationship between a galaxy's properties and its circumgalactic medium (CGM) provides a unique view of how galaxies evolve. We present an interesting edge-on (i=86 degrees) disk galaxy (G1547) where the CGM is probed by a background quasar at a distance of 84 kpc and within 10 degrees of the galaxy major axis. G1547 does not have any detectable CGM absorption down to stringent limits, covering HI (EW$_r$<0.02A, log(N(HI)/cm$^{-2}$)<12.6) and a range of low and high ionisation absorption lines (OI, CII, NII, SiII, CIII, NIII, SiIII, CIV, SiIV, NV and OVI). This system is rare, given the covering fraction of $1.00_{-0.04}^{+0.00}$ for sub-L* galaxies within 50-100 kpc of quasar sightlines. G1547 has a low SFR (1.1 M$_{\odot}$yr$^{-1}$), SSFR ($1.5\times10^{-10}$yr$^{-1}$) and $Σ_{\rm SFR}$ (0.06 M$_{\odot}$yr$^{-1}$kpc$^{-2}$) and does not exhibit AGN or star-formation driven outflows. Compared to the general population of galaxies, G1547 is in the green valley and has an above average metallicity with a negative gradient. When compared to other HI absorption-selected galaxies, we find that quiescent galaxies with log(SSFR/yr$^{-1})<-11$ have a low probability (4/12) of possessing detectable HI in their CGM, while all galaxies (40/40) with log(SSFR/yr$^{-1})>-11$ have HI absorption. We conclude that SSFR is a good indicator of the presence of HI CGM. Interestingly however, G1547 is the only galaxy with log(SSFR/yr$^{-1})>-11$ that has no detectable CGM. Given the properties of G1547, and its absent CGM, it is plausible that G1547 is undergoing quenching due to a lack of accreting fuel for star-formation, with an estimated quenching timescale of $4\pm1$ Gyr. G1547 provides a unique perspective into the external mechanisms that could explain the migration of galaxies into the green valley.
