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arXiv 2404.04780astro-ph.GA
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低红移星系中的射电活动星系核活动与恒星形成率无直接关系

Radio AGN Activity in Low Redshift Galaxies is Not Directly Related to Star Formation Rates

Arjun Suresh, Michael R. Blanton

AI总结:

基于MaNGA、FIRST与NVSS约万个星系样本,研究识别射电AGN并分析其Eddington比率,发现射电AGN活动主要依赖恒星质量,而与恒星形成率无直接关系。

摘要:

我们研究了局域宇宙中射电辐射活动星系核(AGN)的族群特征,并将其作为宿主星系属性(尤其是恒星质量和恒星形成率)的函数进行考察。理论上,射电AGN活动被认为有助于降低星系的恒星形成率,因此研究这两种星系属性之间的关系是自然的。我们使用来自Mapping Nearby Galaxies at APO(MaNGA)巡天的约10,000个星系样本,该巡天是Sloan Digital Sky Survey IV(SDSS-IV)的一部分;同时结合Faint Images of the Radio Sky at Twenty centimeters(FIRST)射电巡天以及National Radio Astronomy Observatory(NRAO)Very Large Array(VLA)Sky Survey(NVSS)。MaNGA中有1,126个星系具有射电探测。利用基于Pipe3D、并由MaNGA高信噪比测量推断得到的恒星形成率和恒星质量估计,我们表明,正如预期,恒星形成率与20 cm射电辐射强相关。我们将那些射电辐射远强于根据恒星形成率所预期水平的射电源识别为射电AGN。利用这一AGN样本、MaNGA中测量良好的恒星速度弥散以及黑洞M-sigma关系,我们考察了Eddington比率分布及其对恒星质量和恒星形成率的依赖。我们发现Eddington比率分布强烈依赖于恒星质量,质量更大的星系具有更大的Eddington比率。与以往研究一致,AGN比例随恒星质量迅速增加。在控制恒星质量后,我们没有发现其对恒星形成率、比恒星形成率或速度弥散存在任何依赖。我们得出结论:星系恒星形成率似乎与射电AGN的存在与否无关,这可能有助于约束AGN反馈的理论模型。

英文摘要:

We examine the demographics of radio-emitting active galactic nuclei (AGN) in the local universe as a function of host galaxy properties, most notably both stellar mass and star formation rate. Radio AGN activity is theoretically implicated in helping reduce star formation rates of galaxies, and therefore it is natural to investigate the relationship between these two galaxy properties. We use a sample of around 10, 000 galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey, part of the Sloan Digital Sky Survey IV (SDSS-IV), along with the Faint Images of the Radio Sky at Twenty centimeters (FIRST) radio survey and the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) Sky Survey (NVSS). There are 1,126 galaxies in MaNGA with radio detections. Using star formation rate and stellar mass estimates based on Pipe3D, inferred from the high signal-to-noise ratio measurements from MaNGA, we show that star formation rates are strongly correlated with 20 cm radio emission, as expected. We identify as radio AGN those radio emitters that are much stronger than expected from the star formation rate. Using this sample of AGN, the well-measured stellar velocity dispersions from MaNGA, and the black hole M-sigma relationship, we examine the Eddington ratio distribution and its dependence on stellar mass and star formation rate. We find that the Eddington ratio distribution depends strongly on stellar mass, with more massive galaxies having larger Eddington ratios. As found in previous studies, the AGN fraction increases rapidly with stellar mass. We do not find any dependence on star formation rate, specific star formation rate, or velocity dispersion when controlling for stellar mass. We conclude that galaxy star formation rates appear to be unrelated to the presence or absence of a radio AGN, which may be useful in constraining theoretical models of AGN feedback.

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