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arXiv 1705.03076astro-ph.GA
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邻近类星体II的积分场谱学。分子气体含量与恒星形成条件

Integral field spectroscopy of nearby QSOs II. The molecular gas content and condition for star formation

B. Husemann, T. A. Davis, K. Jahnke, H. Dannerbauer, T. Urrutia, J. Hodge

摘要:

本文给出了14个低红移类星体的单碟CO(1-0)和CO(2-1)观测结果。结合光学积分场光谱,我们研究了冷气体含量与恒星形成率(SFR)和黑洞吸积率的关系。14例中8例检出CO(1-0),11例中7例检出CO(2-1)。大多数盘主导的类星体揭示气体分数和耗尽时间以及匹配正常的恒星形成系统。两个富含气体的主要合并显示出明显的星爆特征,具有高于平均水平的气体分数和较短的耗尽时间。膨胀为主的类星体主机主要是未检测到的CO(1-0),这对应于,平均而言,较低的气体分数比盘为主的同行。然而,它们的SFR意味着比平均耗尽时间更短,恒星形成效率更高。在我们的样本中,通过移除冷气体的负类星体反馈似乎起着可以忽略的作用。结合文献样本,我们发现了盘主导类星体的黑洞吸积率与分子气体总含量之间的变化趋势。我们解释这是一个上信封的核活动,这是很好地代表了总的和环核气藏可供吸积之间的比例关系。膨胀为主的类星体显着不同的标度关系,并出现不相关的总分子气体含量。这可以通过更致密的气藏、通过流出物从气包中喷出或不同的ISM相组成来解释。

英文摘要:

We present single-dish CO(1-0) and CO(2-1) observations for 14 low-redshift quasi-stellar objects (QSOs). In combination with optical integral field spectroscopy we study how the cold gas content relates to the star formation rate (SFR) and black hole accretion rate. CO(1-0) is detected in 8 of 14 targets and CO(2-1) is detected in 7 out of 11 cases. The majority of disc-dominated QSOs reveal gas fractions and depletion times well matching normal star forming systems. Two gas-rich major mergers show clear starburst signatures with higher than average gas fractions and shorter depletion times. Bulge-dominated QSO hosts are mainly undetected in CO(1-0) which corresponds, on average, to lower gas fractions than in disc-dominated counterparts. Their SFRs however imply shorter than average depletion times and higher star formation efficiencies. Negative QSO feedback through removal of cold gas seems to play a negligible role in our sample. We find a trend between black hole accretion rate and total molecular gas content for disc-dominated QSOs when combined with literature samples. We interpret this as an upper envelope for nuclear activity which is well represented by a scaling relation between the total and circum-nuclear gas reservoir accessible for accretion. Bulge-dominated QSOs significantly differ from that scaling relation and appear uncorrelated with the total molecular gas content. This could be explained either by a more compact gas reservoir, blow out of the gas envelope through outflows, or a different ISM phase composition.

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。

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