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arXiv 1602.00686astro-ph.GA
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CLASH-VLT:从化学富集现象看MACSJ0416.1 - 2403中团星系的绞窄

CLASH-VLT: Strangulation of cluster galaxies in MACSJ0416.1-2403 as seen from their chemical enrichment

C. Maier, U. Kuchner, B. L. Ziegler, M. Verdugo, I. Balestra, M. Girardi, A. Mercurio, P. Rosati, A. Fritz, C. Grillo, M. Nonino, B. Sartoris

摘要:

我们用CLASH-VLT巡天的VIMOS/VLT光谱探测了z = 0.3972的前沿场星系团MACS J0416.1 - 2403,该星系团覆盖了几乎三个维里半径的区域。我们测量通量的5个发射线的76个集群成员,使我们能够毫不含糊地获得O/H气体金属丰度,也SFR从Halpha。对于中等质量,我们发现一个类似的分布的集群和场星系的MZR和质量与sSFR图。与盘状星系相比,膨胀主导的星系团星系平均具有较低的sSFR和较高的O/Hs。我们使用的位置的星系在投影速度与位置相空间分离我们的集群样本到一个区域的物体吸积较长的时间前,最近吸积和下落的星系的区域。我们发现吸积富金属星系的比例更高(63%),而落区富金属星系的比例为28%。第一次发现中等质量星系落入星系团与基本金属丰度关系的预测一致。相比之下,对于已经吸积的恒星形成星系类似的质量,我们发现平均金属丰度高于预测的模型。这一趋势是加剧吸积星系团的最低质量仓,显示金属丰度2 - 3倍高于原始气体流入模型预测。因此,环境效应强烈地影响log(M/Msun)<10.2(Salpeter IMF)星系团的气体调节和控制气体金属丰度。我们还研究了有和没有气体流入的模型星系的化学演化路径,表明需要扼杀来解释吸积星系团的高金属丰度。我们的研究结果有利于扼杀方案中,气体流入停止log(M/Msun)<10.2星系时,星系团吸积。

英文摘要:

(abridged) We explore the Frontier Fields cluster MACS J0416.1-2403 at z=0.3972 with VIMOS/VLT spectroscopy from the CLASH-VLT survey covering a region which corresponds to almost three virial radii. We measure fluxes of 5 emission lines of 76 cluster members enabling us to unambiguously derive O/H gas metallicities, and also SFRs from Halpha. For intermediate massses we find a similar distribution of cluster and field galaxies in the MZR and mass vs. sSFR diagrams. Bulge-dominated cluster galaxies have on average lower sSFRs and higher O/Hs compared to their disk-dominated counterparts. We use the location of galaxies in the projected velocity vs. position phase-space to separate our cluster sample into a region of objects accreted longer time ago and a region of recently accreted and infalling galaxies. We find a higher fraction of accreted metal-rich galaxies (63%) compared to the fraction of 28% of metal-rich galaxies in the infalling regions. Intermediate mass galaxies falling into the cluster for the first time are found to be in agreement with predictions of the fundamental metallicity relation. In contrast, for already accreted star-forming galaxies of similar masses, we find on average metallicities higher than predicted by the models. This trend is intensified for accreted cluster galaxies of the lowest mass bin, that display metallicities 2-3 times higher than predicted by models with primordial gas inflow. Environmental effects therefore strongly influence gas regulations and control gas metallicities of log(M/Msun)<10.2 (Salpeter IMF) cluster galaxies. We also investigate chemical evolutionary paths of model galaxies with and without inflow of gas showing that strangulation is needed to explain the higher metallicities of accreted cluster galaxies. Our results favor a strangulation scenario in which gas inflow stops for log(M/Msun)<10.2 galaxies when accreted by the cluster.

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