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arXiv 1412.7866astro-ph.HEastro-ph.GA
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AGN活动的射电证据:相对论性的SMBH示踪

Radio Evidence for AGN Activity: Relativistic as Tracers of SMBHs

K. I. Kellermann

摘要:

虽然大多数类星体的射电辐射似乎与宿主星系中的恒星形成活动有关,但大约10%的光学选择类星体具有非常明亮的相对论喷流,显然是由位于喷流底部的SMBH提供动力。当这些喷流指向接近视线时,它们的视亮度会因多普勒增强而增强,并且看起来非常可变。高分辨率射电干涉测量直接显示了相对论性等离子体喷流从SMBH流出。在这些所谓的耀变体中,视横向速度通常约为7c,但高达50c,表明真实速度在光速的1%以内。喷流似乎是准直的,并在SMBH下游100秒差距的区域加速。用地空干涉仪进行的测量表明,视亮度温度约为10 E14 K或更高。这远远超过了逆康普顿冷却的极限。从观测到的抛射速度推导出的适度的多普勒因子似乎不足以解释观测到的相对论性增强的高亮度温度。

英文摘要:

Although the radio emission from most quasars appears to be associated with star forming activity in the host galaxy, about ten percent of optically selected quasars have very luminous relativistic jets apparently powered by a SMBH which is located at the base of the jet. When these jets are pointed close to the line of sight their apparent luminosity is enhanced by Doppler boosting and appears highly variable. High resolution radio interferometry shows directly the outflow of relativistic plasma jets from the SMBH. Apparent transverse velocities in these so called blazars are typically about 7c but reach as much as 50c indicating true velocities within one percent of the speed of light. The jets appear to be collimated and accelerated in regions as much as a hundred parsecs downstream from the SMBH. Measurements made with Earth to space interferometers indicate apparent brightness temperatures of about 10E14 K or more. This is well in excess of the limits imposed by inverse Compton cooling. The modest Doppler factors deduced from the observed ejection speeds appear to be inadequate to explain the high observed brightness temperatures in terms of relativistic boosting.

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