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arXiv 1111.3623astro-ph.GA
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棒对中心星形成和AGN活性的影响

Bar effects on central star formation and AGN activity

Seulhee Oh, Kyuseok Oh, Sukyoung K. Yi

摘要:

星系棒通常被认为是气体流入星系中心的通道,并触发中心恒星形成和活动星系核(AGN)活动。然而,基于经验研究的这一问题的现状是令人不安的,特别是活动星系核。我们调查这个问题的基础上斯隆数字巡天(SDSS)数据发布7。从邻近(0.01 < z < 0.05)亮(Mr < -19)星系数据库中,我们通过目视检查构建了6,658个相对面向晚型星系的样本。我们发现36%的人有酒吧。酒吧被发现是更常见的星系较早的形态。这使得样本选择至关重要。基于参数的选择会错过很大一部分早期形态的棒星系。棒对恒星形成或活动星系核的影响很难正确理解,因为多种因素(棒频率,恒星质量,黑洞质量,气体含量等)似乎以复杂的方式对它们做出了贡献。在打破这些简并的希望,我们检查酒吧固定星系属性的影响。在较红的星系中,棒对中心恒星形成的影响似乎更大。另一方面,在蓝色和质量较小的星系中,活动星系核上的棒效应更高。这些影响似乎更明显的增加酒吧的长度。我们讨论了气体含量,酒吧的强度,酒吧的演变,加油的时间尺度,和超大质量黑洞的动力学作用方面的可能影响。

英文摘要:

Galactic bars are often suspected to be a channel of gas inflow to the galactic center and trigger central star formation and active galactic nuclei (AGN) activity. However, the current status on this issue based on empirical studies is unsettling, especially on AGN. We investigate this question based on the Sloan Digital Sky Survey (SDSS) Data Release 7. From the nearby (0.01 < z < 0.05) bright (Mr < -19) database, we have constructed a sample of 6,658 relatively face-on late-type galaxies through visual inspection. We found 36% of them to have a bar. Bars are found to be more common in galaxies with earlier morphology. This makes sample selection critical. Parameter-based selections would miss a large fraction of barred galaxies of early morphology. Bar effects on star formation or AGN are difficult to understand properly because multiple factors (bar frequency, stellar mass, black-hole mass, gas contents, etc.) seem to contribute to them in intricate manners. In the hope of breaking these degeneracies, we inspect bar effects for fixed galaxy properties. Bar effects on central star formation seem higher in redder galaxies. Bar effects on AGN on the other hand are higher in bluer and less massive galaxies. These effects seem more pronounced with increasing bar length. We discuss possible implications in terms of gas contents, bar strength, bar evolution, fueling time-scale, and the dynamical role of supermassive black hole.

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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