On the Jet Production Efficiency in a Sample of the Youngest Radio Galaxies
On the Jet Production Efficiency in a Sample of the Youngest Radio Galaxies
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DOI：
10.3847/1538-4357/ab7930
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发表时间：
2018-05
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影响因子：
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通讯作者：
A. Wójtowicz;Ł. Stawarz;E. Kosmaczewski
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作者：
A. Wójtowicz;Ł. Stawarz;E. Kosmaczewski
本文讨论了17个年轻射电星系的喷流产生效率，测量了红移、运动年龄和核x射线通量，其中观测到的致密喷流/叶和吸积盘的光度对应于AGN活动的同一事件。对于目标，我们分析了现有的光学数据，估计了吸积盘的放热光度Lbol和黑洞质量；我们还得到了最小射流动力学光度Pj。有了这些信息，我们研究了我们的样品在三维空间中的分布，吸积率λEdd≡Lbol/LEdd，核x射线光度LX在这里被认为是圆盘日冕发射的极限，以及Pj，以爱丁顿单位或圆盘光度单位表示后两个参数。我们发现(i)样品的吸积速率λEdd分布在λEdd ~ 0.01 ~ 0.2的狭窄范围内；（ii）归一化射流功率Pj/ led与吸积速率λEdd呈正相关，在最大值λEdd > 0.05处存在一定的饱和；（iii）射流产生效率范围从η射流> 10−3到最大η射流~ 0.2，低于最大自旋黑洞周围磁阻盘的预期水平；(4)在硬度-强度图LX/Lbol−λEdd上，η喷射存在一定的多样性，在高/硬状态时η喷射产生效率最高，在软状态时η喷射被抑制。
Here we discuss the jet production efficiency in a sample of 17 young radio galaxies with measured redshifts, kinematic ages, and nuclear X-ray fluxes, for which the observed luminosities of compact jets/lobes and accretion disks correspond to the same episode of AGN activity. For the targets, we analyze the available optical data, estimating the bolometric luminosities of the accretion disks Lbol, and the black hole masses; we also derive the minimum jet kinetic luminosities, Pj. With this information we investigate the distribution of our sample in the three-dimensional space of the accretion rate λEdd ≡ Lbol/LEdd, the nuclear X-ray luminosity LX considered here as a limit for the emission of the disk coronae, and Pj, expressing the latter two parameters either in the Eddington units, or in the units of the disk luminosity. We find that (i) the accretion rate λEdd in our sample is distributed within a narrow range λEdd ∼ 0.01–0.2; (ii) the normalized jet power Pj/LEdd formally correlates with the accretion rate λEdd, with some saturation at the largest values λEdd > 0.05; (iii) the jet production efficiency spans a range from ηjet ≲ 10−3 up to ∼0.2 at maximum, which is below the level expected for magnetically arrested disks around maximally spinning black holes; and (iv) there is a diversification in ηjet on the hardness–intensity diagram LX/Lbol − λEdd, with the jets being produced most efficiently during the high/hard states, and suppressed during the soft states.