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arXiv 1302.6237astro-ph.CO
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黑洞标度关系的强环境依赖性

The strong environmental dependence of black hole scaling relations

Sean L. McGee

摘要:

我们研究了中心黑洞质量(Mbh)和宿主星系性质(速度色散、球核恒星质量和球核光度)之间的标度关系如何依赖于大尺度环境。对于每个样本的69个星系的动态黑洞测量,我们编译四个环境措施(最近邻距离,固定孔径数密度,总晕质量,和中央/卫星)。我们发现,中央星系和卫星星系遵循明显不同的标度在每一个我们已经检查过的三个关系。中央星系的Mbh - sigma关系比卫星星系的Mbh-sigma关系(6.38 +/- 0.49)陡峭得多(4.91 +/- 0.49),但截距相似。这种行为仍然存在,即使在限制到只有早期类型的星系样本或删除8个最明亮的星系团星系后。当基于其他环境指标分割样本时,Mbh - sigma关系显示出更适度的差异,这表明它们是由底层卫星/中心分数驱动的。在黑洞质量和膨胀恒星质量或膨胀光度之间的幂律标度中也可以看到中心和卫星的单独关系。我们认为,富含气体的低质量星系在成为卫星星系的过程中,会经历一个黑洞快速增长的时期。如果中心星系在当前的Mbh - sigma关系是卫星人口的代表性祖先,观测意味着sigma = 120 km/s的星系必须接近其中心黑洞质量的三倍。大质量中心星系的黑洞质量升高,是卫星星系吸积的自然结果。

英文摘要:

We investigate how the scaling relations between central black hole mass (Mbh) and host galaxy properties (velocity dispersion, bulge stellar mass and bulge luminosity) depend on the large scale environment. For each of a sample of 69 galaxies with dynamical black hole measurements we compile four environmental measures (nearest neighbor distance, fixed aperture number density, total halo mass, and central/satellite). We find that central and satellite galaxies follow distinctly separate scalings in each of the three relations we have examined. The Mbh - sigma relation of central galaxies is significantly steeper (6.38 +/- 0.49) than that of satellite galaxies (4.91 +/- 0.49), but has a similar intercept. This behavior remains even after restricting to a sample of only early type galaxies or after removing the 8 brightest cluster galaxies. The Mbh - sigma relation shows more modest differences when splitting the sample based on the other environmental indicators, suggesting that they are driven by the underlying satellite/central fractions. Separate relations for centrals and satellites are also seen in the power law scaling between black hole mass and bulge stellar mass or bulge luminosity. We suggest that gas rich, low mass galaxies undergo a period of rapid black hole growth in the process of becoming satellites. If central galaxies on the current Mbh - sigma relation are representative progenitors of the satellite population, the observations imply that a sigma = 120 km/s galaxy must nearly triple its central black hole mass. The elevated black hole masses of massive central galaxies are then a natural consequence of the accretion of satellites.

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