AI 中文总结
研究用特定星系样本探讨运动学未对齐气体吸积对星系恒星形成的影响，通过表征相关参数得出径向分布，发现该吸积在低质量星系能供能，中等质量星系影响最强，高质量星系中作用被稀释，且有无核活动的未对齐星系电离气体中心集中度相似。
AI 中文摘要
近期研究表明，运动学上未对齐气体的吸积为星系的中心物质库提供燃料，引发核活动和恒星形成。本文表明，这种特定吸积通道仅能在恒星质量$M_* \lesssim 10^{10} {\rm M_\odot}$的星系中维持主序恒星形成水平。利用201个运动学未对齐星系样本及3689个对齐星系比较样本，研究未对齐气体对恒星形成的影响。通过表征样本的全球特定恒星形成率、中心集中度和电离气体质量，得出特定恒星形成率和电离气体质量面密度的径向分布。发现未对齐星系的电离气体比对齐星系更集中于中心，在中等质量星系中增强最强，低质量星系中未对齐气体为核恒星形成供能，高质量星系中新增气体影响被稀释。结果还表明有无核活动的未对齐星系电离气体中心集中度相似。
英文摘要
Recent studies have shown that the accretion of kinematically misaligned gas fuels the central reservoir of galaxies, triggering nuclear activity and star formation. In this work, we show that this specific accretion channel can only sustain main-sequence levels of star formation in galaxies with $M_* \lesssim 10^{10} {\rm M_\odot}$. Using a sample of 201 kinematically misaligned galaxies, and a comparison sample of 3689 aligned galaxies, from the Mapping Nearby Galaxies at Apache Point Observatory survey, we investigate the impact of kinematically misaligned gas on star formation across stellar mass. We characterise the global specific star formation rate, central concentration and mass of ionized gas of our samples, and derive radial profiles of specific star formation rate and ionized gas mass surface density. We find that misaligned galaxies exhibit more centrally concentrated ionized gas than their aligned counterparts, with the strongest enhancement occurring at intermediate masses ($10^{10}$-$10^{10.6} {\rm M_\odot}$), where the central ionized gas density peaks. In galaxies less massive than $10^{10} {\rm M_\odot}$, misaligned gas fuels nuclear star formation at rates typical of star-forming systems. At higher masses, however, the impact of this newly accreted gas is diluted by the larger pre-existing stellar mass in the central regions, limiting its ability to rejuvenate the star formation activity in these galaxies. Our results also show that misaligned galaxies with or without nuclear activity exhibit similar central concentrations of ionized gas, suggesting that most have a reservoir capable of fuelling their supermassive black holes over timescales longer than typical nuclear activity episodes.
CommentsAccepted for publication in MNRAS. 15 pages, 13 figures
