论文标题
星系的颜色梯度和半质量半径，到$ z = 2 $/3D-HST字段：进一步的证据证明了大规模加权和轻度加权尺寸进化的重要差异
Color gradients and half-mass radii of galaxies out to $z=2$ in the CANDELS/3D-HST fields: further evidence for important differences in the evolution of mass-weighted and light-weighted sizes
论文作者
论文摘要
最近的研究表明，半质量和半光半径之间的比率，$ r _ {\ rm质量} / r _ {\ rm light} $，随着恒星质量和红移的函数而差异很大，使无处不在的$ r _ {\ rm lim} {\ rm rm lim} - m _ m _ $ _ m _*$ reaserions的解释变得复杂。为了调查，在这项研究中，我们使用$ \ log \，m _*/m _*/m _*/m _ \ odot> 10.25 $构建$ \ sim 3000 $星系的光和色谱，使用$ \ texttt {imcascade} $，一种贝叶斯的贝叶斯实施了多类 - 高斯扩张（MGE）的技术。 $ \ texttt {imcascade} $使用一系列高斯人灵活地表示星系剖面，没有任何A-Priori参数化。我们发现，恒星形成和静态星系平均具有负颜色梯度。对于星形形成星系，我们发现更陡峭的梯度随红移而演变，并且与灰尘含量相关。使用颜色梯度作为$ m/l $比例的梯度代理，我们为星系样本测量半径半径。单个$ r _ {\ rm质量} / r _ {\ rm light} $比率有明显的分散，这与颜色梯度的变化相关。我们发现中值$ r _ {\ rm质量} / r _ {\ rm light} $比率从0.75 at $ z = 2 $ = 2 $ = 2 $ to $ z = 1 $，与以前的结果一致。我们表征了$ r _ {\ rm质量} - m _*$关系，我们发现它具有较浅的斜率，并且与$ r _ {\ rm light} - m _*$关系相比，红移的进化较小。这既适用于恒星形成和静态星系。我们讨论了使用$ r _ {\ rm质量} $而不是$ r _ {\ rm light} $的一些含义，包括对尺寸 - 倾斜偏置的调查以及与数值模拟的比较。
Recent studies have indicated that the ratio between half-mass and half-light radii, $r_{\rm mass} / r_{\rm light}$, varies significantly as a function of stellar mass and redshift, complicating the interpretation of the ubiquitous $r_{\rm light}- M_*$ relation. To investigate, in this study we construct the light and color profiles of $\sim 3000$ galaxies at $1<z<2$ with $\log\, M_*/M_\odot > 10.25$ using $\texttt{imcascade}$, a Bayesian implementation of the Multi-Gaussian expansion (MGE) technique. $\texttt{imcascade}$ flexibly represents galaxy profiles using a series of Gaussians, free of any a-priori parameterization. We find that both star-forming and quiescent galaxies have on average negative color gradients. For star forming galaxies, we find steeper gradients that evolve with redshift and correlate with dust content. Using the color gradients as a proxy for gradients in the $M/L$ ratio we measure half mass radii for our sample of galaxies. There is significant scatter in individual $r_{\rm mass} / r_{\rm light}$ ratios, which is correlated with variation in the color gradients. We find that the median $r_{\rm mass} / r_{\rm light}$ ratio evolves from 0.75 at $z=2$ to 0.5 at $z=1$, consistent with previous results. We characterize the $r_{\rm mass}- M_*$ relation and we find that it has a shallower slope and shows less redshift evolution than the $r_{\rm light} - M_*$ relation. This applies both to star-forming and quiescent galaxies. We discuss some of the implications of using $r_{\rm mass}$ instead of $r_{\rm light}$, including an investigation of the size-inclination bias and a comparison to numerical simulations.
