arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0903.5310astro-ph.HEastro-ph.GA
收藏

Seyfers中定标紫外外流

Scaling ultraviolet outflows in Seyferts

R. Stoll, S. Mathur, Y. Krongold, F. Nicastro

摘要:

在活动星系核中经常可以看到X射线和紫外吸收外流,并被认为是一种可能的反馈机制。它们是否能提供足够的反馈取决于它们的质量和携带的能量,但更根本的是取决于它们是否能逃脱黑洞的势能。如果我们观察到流出时,流出已经达到了它们的渐近速度,那么所有这些性质都严重依赖于流出的半径:一个难以测量的值。X射线暖吸收体与电离源之间距离的最严格限制是Krongold等人(2007)对NGC 4051的限制。我们使用NGC 4051来模拟其他观测到的紫外线外流,发现总体上它们可能不会提供有意义的反馈。流出速度低于或略高于黑洞的逃逸速度。这可能是因为它们尚未完全加速,或者高速流出的占空比可能很小。另一种可能性是,它们可能只在更高光度的活动星系核中提供有意义的反馈,因为我们发现外流速度与逃逸速度的比值与活动星系核连续光度之间的相关性很弱。

英文摘要:

X-ray and UV absorbing outflows are frequently seen in AGN and have been cited as a possible feedback mechanism. Whether or not they can provide adequate feedback depends on how massive they are and how much energy they carry, but it depends in a more fundamental way upon whether they escape the potential of the black hole. If the outflows have reached their asymptotic velocity when we observe them, then all of these properties critically depend on the radius of the outflow: a value which is difficult to measure. The tightest limit on the distance of an X-ray warm absorber from the ionizing source is that of Krongold et al. (2007) for NGC 4051. We use NGC 4051 to model other observed UV outflows, and find that on the whole they may not provide meaningful feedback. The outflow velocities are below or just above the escape velocity of the black hole. This may be because they are not yet fully accelerated, or the duty cycle of high-velocity outflows may be small. Another possibility is that they may only provide meaningful feedback in higher-luminosity AGN, as we find a weak correlation between the ratio of outflow velocity to escape velocity and AGN continuum luminosity.

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。

↑