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arXiv 0709.0183astro-ph
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慢质量宽喷流的形成

The Formation of Slow-Massive-Wide Jets

Noam Soker

摘要:

我提出了一个模型的形成慢质量宽(SMW)喷流的吸积盘在紧凑的对象。这项研究的动机是声称在一些天体物理物体中存在SMW喷流,例如行星状星云(PN)和星系中的一些活动星系核以及冷却流团中。在这个模型中,能量仍然来自致密物体的吸积。吸积盘发射两个相反的喷流,速度的数量级的逃逸速度从吸积物体和质量流出率的吸积率的1-20%,在最流行的模型喷射发射;在本模型中,这些被称为快速第一级(FFS)喷流。然而,FFS喷流遇到周围的气体,起源于质量吸积过程中,并终止于强烈的冲击接近其起源。形成两个热气泡。这些气泡加速周围的气体,形成两个SMW射流,它们比FFS射流质量更大,速度更慢。这一机制要发挥作用有两个条件。首先,周围的气体应该足够大,以阻止FFS射流的自由膨胀。最有效的是,当周围的气体被补充时,实现这种条件。其次,辐射能量损失必须很小。

英文摘要:

I propose a model for the formation of slow-massive-wide (SMW) jets by accretion disks around compact objects. This study is motivated by claims for the existence of SMW jets in some astrophysical objects such as in planetary nebulae (PNs) and in some active galactic nuclei in galaxies and in cooling flow clusters. In this model the energy still comes from accretion onto a compact object. The accretion disk launches two opposite jets with velocity of the order of the escape velocity from the accreting object and with mass outflow rate of ~1-20% of the accretion rate as in most popular models for jet launching; in the present model these are termed fast-first-stage (FFS) jets. However, the FFS jets encounter surrounding gas that originates in the mass accretion process, and are terminated by strong shocks close to their origin. Two hot bubbles are formed. These bubbles accelerate the surrounding gas to form two SMW jets that are more massive and slower than the FFS jets. There are two conditions for this mechanism to work. Firstly, the surrounding gas should be massive enough to block the free expansion of the FFS jets. Most efficiently this condition is achieved when the surrounding gas is replenished. Secondly, the radiative energy losses must be small.

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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