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arXiv 0909.5096astro-ph.CO
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Mrk 231亚秒差距结构的VLBA观测:相对论性喷流与BAL风的相互作用

VLBA Observations of Sub-Parsec Structure in Mrk 231: Interaction between a Relativistic Jet and a BAL Wind

Cormac Reynolds, Brian Punsly, Preeti Kharb, Christopher P. O'Dea, Joan Wrobel

摘要:

本文报道了对邻近宽吸收线类星体Mrk 231的首次高频VLBI观测。在15 GHz和22 GHz进行了三次观测,其中两次还包括43 GHz的观测。核射电源被分解为一个紧凑的双。核心组件经历了一次强烈的耀斑,其中在22 GHz的通量密度增加了$> 150%$(45 mJy),在三个月。理论模型的耀斑意味着,排放可能是增强了非常强大的多普勒助推的高度相对论性喷出物的动能通量,$Q \sim 3 \times 10^{43} \mathrm{ergs/sec}$。结合我们的数据与前两个时代的15 GHz的数据,显示边缘的证据缓慢推进的第二个组成部分(位于$\approx 0.97$ PC从核心)超过9.4年的跨度。我们估计了次级粒子在$\bar{Q}\approx 10^{42}\mathrm{ergs/sec}$的长期时均动能通量。低频VLBA观测表明,次级是通过自由-自由吸收气体的护罩看到的,其发射测量值为$\approx 10^{8} \mathrm{cm}^{-6}\mathrm{pc}$。陡峭的频谱的二次分量似乎是一个紧凑的无线电波瓣,这是与工作表面之间的冲压压力约束射流,和一个稠密的介质,很可能是源的自由-自由吸收。稠密气体的性质是一致的温度,从核位移和总氢的柱密度通常与BAL风。

英文摘要:

We report on the first high frequency VLBI observations of the nearby broad absorption line quasar (BALQSO), Mrk 231. Three epochs of observations were achieved at 15 GHz and 22 GHz, two of these included 43 GHz observations as well. The nuclear radio source is resolved as a compact double. The core component experienced a strong flare in which the flux density at 22 GHz increased by $> 150%$ (45 mJy) in three months. Theoretical models of the flare imply that the emission is likely enhanced by very strong Doppler boosting of a highly relativistic ejecta with a kinetic energy flux, $Q \sim 3 \times 10^{43} \mathrm{ergs/sec}$. Combining our data with two previous epochs of 15 GHz data, shows marginal evidence for the slow advance of the secondary component (located $\approx 0.97$ pc from the core) over a 9.4 year span. We estimate that the long term time averaged kinetic energy flux of the secondary at $\bar{Q}\approx 10^{42}\mathrm{ergs/sec}$. Low frequency VLBA observations indicate that the secondary is seen through a shroud of free-free absorbing gas with an emission measure of $\approx 10^{8} \mathrm{cm}^{-6}\mathrm{pc}$. The steep spectrum secondary component appears to be a compact radio lobe that is associated with a working surface between the ram-pressure confined jet, and a dense medium that is likely to be the source of the free-free absorption. The properties of the dense gas are consistent with the temperatures, displacement from the nucleus and the column density of total hydrogen commonly associated with the BAL wind.

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