X-ray scaling relations of early-type galaxies in IllustrisTNG and a new way of identifying backsplash objects
X-ray scaling relations of early-type galaxies in IllustrisTNG and a new way of identifying backsplash objects
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IllustrisTNG 中早期型星系的 X 射线尺度关系以及识别后溅天体的新方法
DOI：
10.1093/mnras/stad3629
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发表时间：
2023
影响因子：
4.8
通讯作者：
Lin, Wenjie
中科院分区：
文献类型：
--
作者：
Wang, Yunchong;Vogelsberger, Mark;Kim, Dong-Woo;Borrow, Josh;Smith, Aaron;Hernquist, Lars;Lin, Wenjie
我们研究了反馈和环境如何塑造早型星系（ETG）的X射线标度关系，特别是在低质量端。我们从IllustrisTNG的TNG 100盒中选择具有恒星质量的中心ETG。利用MOCK-X管道计算了ETG晕R500以内的模拟X射线光度（LX，500）和类光谱温度（Tsl，500）。在5个有效半径内，LX，500与总质量之间的标度（）与Chandra观测到的ETG吻合得很好。IllustrisTNG再现了观测到的LX，500向较低质量散射的增加，我们发现具有高于平均LX，500的ETG在历史上经历了系统性的较低累积动能AGN反馈能量（低于平均值的ETG反之亦然）。这导致更大的气体质量分数和更年轻的恒星群体，具有更强的恒星反馈加热，一致导致高于平均水平的LX，500。LX，500-Tsl，500关系显示出与观测到的ETG相似的斜率，但模拟系统地低估了气体温度。三个远低于LX-TSL关系的异常值最近都与较大的星系团相互作用，并表现出明显的环境加热特征。我们认为，这些后溅ETG在theLX-Tslplane的独特位置可以提供一种新的方式来识别后溅星系在未来的X射线调查。
We investigate how feedback and environment shapes the X-ray scaling relations of early-type galaxies (ETGs), especially at the low-mass end. We select central-ETGs from the TNG100 box of IllustrisTNG that have stellar masses. We derive mock X-ray luminosity (LX, 500) and spectroscopic-like temperature (Tsl, 500) of hot gas withinR500of the ETG haloes using the MOCK-X pipeline. The scaling betweenLX, 500and the total mass within 5 effective radii () agrees well with observed ETGs fromChandra. IllustrisTNG reproduces the observed increase in scatter ofLX, 500towards lower masses, and we find that ETGs withwith above-averageLX, 500experienced systematically lower cumulative kinetic AGN feedback energy historically (vice versa for below-average ETGs). This leads to larger gas mass fractions and younger stellar populations with stronger stellar feedback heating, concertedly resulting in the above-averageLX, 500. TheLX, 500–Tsl, 500relation shows a similar slope to the observed ETGs but the simulation systematically underestimates the gas temperature. Three outliers that lie far below theLX–Tslrelation all interacted with larger galaxy clusters recently and demonstrate clear features of environmental heating. We propose that the distinct location of these backsplash ETGs in theLX–Tslplane could provide a new way of identifying backsplash galaxies in future X-ray surveys.