Aborted jets and the X–ray emission of radio–quiet AGNs
Aborted jets and the X–ray emission of radio–quiet AGNs
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DOI：
10.1051/0004-6361:20031562
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发表时间：
2003-10
影响因子：
6.5
通讯作者：
G. Ghisellini;F. Haardt;G. Matt
中科院分区：
文献类型：
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作者：
G. Ghisellini;F. Haardt;G. Matt
我们提出，无线电宁静类星体和塞弗特星系有中央黑洞的动力流出和喷流，传播只有很短的距离，因为喷出的物质的速度小于逃逸速度。我们称之为“流产”喷气机。如果中央引擎间歇性地工作，可能会产生材料的斑点，这些斑点可以达到最大径向距离，然后回落，与稍后产生的斑点碰撞，并且仍然向外移动。这些碰撞通过加热等离子体来耗散斑点的大量动能，并且可以（完全或至少部分地）负责无线电安静物体中的高能发射的产生。这是替代更传统的方案，其中无线电安静源的X射线光谱起源于吸积盘上方的热（可能是斑块状）日冕。在后一种情况下，气盘和日冕发射的最终能量来源是吸积。在这里，我们提出，高能辐射也是由黑洞（可能还有盘）的旋转能量的提取提供动力的。利用蒙特卡洛模拟计算了射电宁静活动星系核和银河系黑洞源的含时光谱和光变曲线，并讨论了它们与X射线光谱的关系。特别是，我们表明，时间的变化和光谱是类似的窄线塞弗特1星系中观察到的。
We propose that radio-quiet quasars and Seyfert galaxies have central black holes powering outflows and jets which propagate only for a short distance, because the velocity of the ejected material is smaller than the escape velocity. We call them "aborted" jets. If the central engine works intermittently, blobs of material may be produced, which can reach a maximum radial distance and then fall back, colliding with the blobs produced later and still moving outwards. These collisions dissipate the bulk kinetic energy of the blobs by heating the plasma, and can be responsible (entirely or at least in part) for the generation of the high energy emission in radio-quiet objects. This is alternative to the more conventional scenario in which the X-ray spectrum of radio-quiet sources originates in a hot (and possibly patchy) corona above the accretion disk. In the latter case the ultimate source of energy of the emission of both the disk and the corona is accretion. Here we instead propose that the high energy emission is powered also by the extraction of the rotational energy of the black hole (and possibly of the disk). By means of Montecarlo simulations we calculate the time dependent spectra and light curves, and discuss their relevance to the X-ray spectra in radio-quiet AGNs and galactic black hole sources. In particular, we show that time variability and spectra are similar to those observed in Narrow Line Seyfert 1 galaxies.