论文标题
潮汐特征的频率与年龄和早期类型星系的内部结构相关
Frequency of Tidal Features Correlates with Age and Internal Structure of Early-type Galaxies
论文作者
论文摘要
先前的研究表明，紧凑的年轻早期型星系（ETG）是由最近的合并形成的。但是，尚未透露是否在紧凑的年轻ETG周围经常检测到最近合并的直接证据的潮汐特征。在这里，我们调查了具有ETG的年龄和内部结构（紧凑，颜色梯度和防尘车道）的ETG的比例如何，使用650 $ M_R \ le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le-le z \ le le z \ le le z \ le0.055 $的ETG的eTG sloan slipe slore是co的co。我们发现，在年轻的ETG和更紧凑的ETG中，潮汐功能更为频繁，因此，与年龄的$ f_ {t} $相比，$ \ sim0.7 $的紧凑型年轻ETG具有高$ f_ {t} $，而$ \ gtrsim9 $ gyr的较不那么紧凑或旧的旧配件$ \ gtrsim9 $ gyr，$ \ gtrsim9 $ gyr的$ f _;在紧凑的年轻ETG中，那些具有蓝色内核的人的$ \ sim3 $ $ f_ {t} $比有红色核心的人高。此外，与没有防尘车道的ETG相比，带有防尘车道的ETG具有$ \ sim4 $倍$ f_ {t} $。我们的结果提供了直接的证据表明，最近合并涉及紧凑的年轻ETG，尤其是与蓝色核心和具有灰尘车道的ETG。根据我们的结果和几个其他假设，我们粗略地估计了合并后潮汐特征的典型可见时间，这是$ \ sim3 $ gyr在Stripe 82共添加图像的深度中。
Previous studies suggest that compact young early-type galaxies (ETGs) were formed by recent mergers. However, it has not yet been revealed whether tidal features that are direct evidence of recent mergers are detected frequently around compact young ETGs. Here, we investigate how the fraction of ETGs having tidal features ($f_{T}$) depends on age and internal structure (compactness, color gradient, and dust lanes) of ETGs, using 650 ETGs with $M_r\le-19.5$ in $0.015\le z\le0.055$ that are in deep coadded images of the Stripe 82 region of the Sloan Digital Sky Survey. We find that tidal features are more frequent in younger ETGs and more compact ETGs, so that compact young ETGs with ages $\lesssim6$ Gyr have high $f_{T}$ of $\sim0.7$ compared to their less compact or old counterparts with ages $\gtrsim9$ Gyr that have $f_{T}\lesssim0.1$. Among compact young ETGs, those with blue cores have $\sim3$ times higher $f_{T}$ than those with red cores. In addition, ETGs with dust lanes have $\sim4$ times higher $f_{T}$ than those without dust lanes. Our results provide direct evidence that compact young ETGs especially with blue cores and ETGs with dust lanes are involved in recent mergers. Based on our results and several additional assumptions, we roughly estimate the typical visible time of tidal features after a merger, which is $\sim3$ Gyr in the depth of the Stripe 82 coadded images.
