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arXiv 0801.4560astro-ph
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窄线塞弗特1星系中的黑洞质量真的很小吗?

Are the black hole masses in Narrow Line Seyfert 1 galaxies actually small?

R. Decarli, M. Dotti, M. Fontana, F. Haardt

摘要:

窄线塞弗特1星系(NLS 1)通常被认为是第一类活动星系核中的特殊天体,因为宽线的宽度相对较小,强X射线变化,软X射线连续谱,弱[OIII]和强Fe II线强度。中心大质量黑洞(MBH)的质量M_BH比已知的MBH-宿主星系标度关系所估计的要小,而吸积率则比Seyfert 1星系的平均吸积率大。在这封信中,我们表明,NLS 1特有的M_BH和L/L_Edd原来是相当标准的,只要宽线区域被允许有一个盘状,而不是各向同性,几何形状。假设NLS 1 s是沿着盘轴观察的相当“正常”的塞弗特1天体,我们可以从被归类为NLS 1 s的塞弗特1的分数中估计出典型的倾角,并计算出与观测到的宽线半高宽和MBH维里质量相关的几何因子。我们表明,几何因子可以完全解释的“黑洞质量赤字”观察到的NLS 1,和L/L_Edd(平均)的值相比,更常见的宽线塞弗特1星系。

英文摘要:

Narrow Line Seyfert 1 galaxies (NLS1s) are generally considered peculiar objects among the broad class of Type 1 active galactic nuclei, due to the relatively small width of the broad lines, strong X-ray variability, soft X-ray continua, weak [OIII], and strong FeII line intensities. The mass M_BH of the central massive black hole (MBH) is claimed to be lighter than expected from known MBH-host galaxy scaling relations, while the accretion rate onto the MBH larger than the average value appropriate to Seyfert 1 galaxies. In this Letter, we show that NLS1 peculiar M_BH and L/L_Edd turn out to be fairly standard, provided that the broad line region is allowed to have a disc-like, rather than isotropic, geometry. Assuming that NLS1s are rather ``normal'' Seyfert 1 objects seen along the disc axis, we could estimate the typical inclination angles from the fraction of Seyfert 1 classified as NLS1s, and compute the geometrical factor relating the observed FWHM of broad lines to the virial mass of the MBH. We show that the geometrical factor can fully account for the "black hole mass deficit" observed in NLS1s, and that L/L_Edd is (on average) comparable to the value of the more common broad line Seyfert 1 galaxies.

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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