AI 中文总结
该研究对105个变貌活动星系核的寄主星系展开分析，发现多数寄主为宁静星系，其性质与同条件延展类星体大体一致，结果支持中心超大质量黑洞吸积率变化是变貌活动星系核转变的主要起源。
AI 中文摘要
变貌活动星系核（CL AGNs）追踪核活动的快速变化，但它们与寄主星系性质的关联仍不清楚。我们对105个此前通过比较DESI与SDSS数据筛选出的CL AGNs的寄主星系展开研究，对这105个天体的DESI和SDSS光谱应用双历元分光光度分解，同时利用HSC图像约束其变化的AGN成分与非变化的恒星种群成分。我们发现，105个CL AGNs的寄主星系中有79个（75.2%）为宁静星系，31个（29.5%）还呈现出后星暴特征。我们聚焦于HSC图像中具有延展寄主发射的82个CL AGNs，并将它们与红移、恒星质量相近的延展类星体进行比较；尽管CL AGNs的寄主星系中后星暴星系更为常见，但它们的恒星形成活动、巴尔末吸收及宁静星系占比与比较类星体大体一致。具有延展寄主发射的CL AGNs比形态致密的同类天体更常为宁静星系，但在红移与恒星质量匹配后，该差异不再明显。O II与O III窄线未呈现出种群层面上对连续谱和宽线变化的响应，这与窄线区预期的较慢响应一致。综上，这些结果支持中心超大质量黑洞吸积率的变化是CL转变的主要起源。
英文摘要
Changing-look (CL) AGNs trace rapid changes in nuclear activity, but their connection to host galaxy properties remains unclear. We present a study of the host galaxies of 105 CL AGNs previously selected by comparing DESI and SDSS data. We apply a two-epoch spectrophotometric decomposition to the DESI and SDSS spectra of the 105 objects. Meanwhile, HSC images are used to constrain their varying AGN components and non-varying stellar population components. We find that 79 of the 105 (75.2%) CL AGN hosts are quiescent galaxies, and 31/105 (29.5%) also show post-starburst signatures. We focus on 82 CL AGNs with extended host emission in the HSC images and compare them with extended quasars at similar redshift and stellar mass. Their star formation activity, Balmer absorption, and quiescent fractions are broadly consistent with those of the comparison quasars, although post-starburst hosts are more common among the CL AGNs. Our CL AGNs with extended host emission are more often quiescent than those with compact morphology, but this difference is not apparent after matching in redshift and stellar mass. The $\mathrm{O\, \small II}$ and $\mathrm{O\, \small III}$ narrow lines show no population-wide response to the continuum and broad line changes, consistent with the slower response expected from the narrow line region. Together, these results favor changes in the central supermassive black hole accretion rate as the main origin of the CL transitions.
CommentsSubmitted to The Astrophysical Journal; 20 pages, 12 figures
