arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1906.01902astro-ph.GA
收藏

团簇环境中蓝心矮早型星系形成的运动学研究

Formation of Blue-cored Dwarf Early-type Galaxies in a Cluster Environment: a Kinematical Perspective

Jiwon Chung, Soo-Chang Rey, Eon-Chang Sung, Suk Kim, Youngdae Lee, Woong Lee

摘要:

在星系团中的一些矮早型星系中存在蓝核,这表明晚型星系的坍缩和随后向红色静止的早型星系的转变。我们提出了双子座多目标摄谱仪长缝光谱的两个dE(bc)的蓝色核心,EVCC 591和EVCC 516,分别位于核心和外围的室女星系团。我们得到了它们沿主轴的内部运动学,至少,~ 1有效半径。EVCC 591显示了一个大小为2”(160 pc)的运动学解耦核心(KDC)的证据,相对于其宿主星系的主体呈现出反向的速度模式。EVCC 591内部区域的恒星成分的自转曲线比星系其他区域的恒星成分的自转曲线陡峭。另一方面,EVCC 516的恒星和电离气体成分的总体速度分布没有显示出显著旋转的特征。随着中央恒星的形成,在内部运动学中发生了KDC和零旋转,这支持了在这两个dE(bc)的形成过程中富含气体的矮星-矮星合并的情景。此外,进化的dE(bc)的集群环境中的普通的dE与KDC是可能的,根据其结构特性。我们认为,在室女星系团中,至少有一些dE(bc)s是在低密度环境中通过矮-矮合并形成的,然后它们落入星系团中;然后它们被星系团环境中的后续效应淬灭。

英文摘要:

The presence of blue cores in some dwarf early-type galaxies (dEs) in galaxy clusters suggests the scenario of late-type galaxy infall and subsequent transformation into red, quiescent dEs. We present Gemini Multi-Object Spectrographs long-slit spectroscopy of two dEs with blue cores (dE(bc)s), EVCC 591 and EVCC 516, located at the core and outskirt of the Virgo cluster, respectively. We obtained their internal kinematics along the major axis out to, at least, ~ 1 effective radius. EVCC 591 shows evidence of a kinematically decoupled core (KDC) with a size of 2" (160 pc), exhibiting an inverted pattern for velocity with respect to the main body of its host galaxy. The rotation curve of the stellar component in the inner region of EVCC 591 is steeper than that in the rest of the galaxy. On the other hand, overall velocity profiles of stellar and ionized gas components of EVCC 516 show no signature of significant rotation. The occurrence of a KDC and zero rotation in the internal kinematics along with the central star formation support the scenario of gas-rich dwarf-dwarf mergers in the formation of these two dE(bc)s. Furthermore, evolution of dE(bc)s in a cluster environment into ordinary dEs with KDCs is possible based on their structural properties. We suggest that at least some of the dE(bc)s in the Virgo cluster were formed through dwarf-dwarf mergers in lower density environments before they subsequently fell into the cluster; they were then quenched by subsequent effects within the cluster environment.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑