Radiatively driven mass accretion on to galactic nuclei by circumnuclear starbursts
Radiatively driven mass accretion on to galactic nuclei by circumnuclear starbursts
复制标题
核周星暴辐射驱动的星系核质量吸积
DOI：
10.1046/j.1365-8711.1998.01862.x
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发表时间：
1998
影响因子：
4.8
通讯作者：
S. Mineshige
中科院分区：
文献类型：
--
作者：
M. Umemura;J. Fukue;S. Mineshige
我们研究的物理过程中，辐射驱动的质量吸积星系核，由于强烈的辐射环核星爆。星暴的辐射不仅通过辐射通量力使内部气体盘收缩，而且由于相对论辐射拖曳，还提取角动量，从而引起盘表面层的雪崩。为了分析这种机制，辐射流体动力学方程求解，包括辐射阻力以及辐射通量力的影响。结果表明，辐射雪崩引起的质量吸积率在半径r处满足Mtec（r）= η（L*/c2）（r/R）2（ΔR/R）（1 − e−τ），其中η的取值范围为0.2 ~ 1，L* 和R分别为辐射光度和星暴环半径，ΔR为辐射区的范围，τ是光盘的正面光学深度。在光学厚度范围内，速率既不取决于光学深度，也不取决于光盘的表面质量密度分布。目前的辐射驱动的质量吸积可能提供了一个物理机制，使质量吸积从100-pc尺度下降到100秒差距尺度，它可能最终与对流主导的粘性吸积到一个大质量黑洞。简要讨论了圆盘的辐射流体动力学和自引力不稳定性。特别是，辐射加速可能会形成一堵尘埃墙，在侧面视图中“遮蔽”了原子核。这提供了另一个版本的模型形成的一个模糊的环面。
We examine the physical processes of radiatively driven mass accretion on to galactic nuclei, owing to intensive radiation from circumnuclear starbursts. The radiation from a starburst not only causes the inner gas disc to contract via radition flux force, but also extracts angular momentum owing to relativistic radiation drag, thereby inducing an avalanche of the surface layer of the disc. To analyse such a mechanism, the radiation–hydrodynamical equations are solved, including the effects of the radiation drag force as well as the radiation flux force. As a result, it is found that the mass accretion rate owing to the radiative avalanche is given by M˙ (r)= η (L*/c2)(r/R)2 (ΔR/R)(1 − e−τ) at radius r, where the efficiency η ranges from 0.2 up to 1, L* and R are respectively the bolometric luminosity and the radius of the starburst ring, ΔR is the extent of the emission regions, and τ is the face-on optical depth of the disc. In an optically thick regime, the rate depends upon neither the optical depth nor the surface mass density distribution of the disc. The present radiatively driven mass accretion may provide a physical mechanism which enables mass accretion from 100-pc scales down to ∼ parsec scales, and it may eventually be linked to advection-dominated viscous accretion on to a massive black hole. The radiation–hydrodynamical and self-gravitational instabilities of the disc are briefly discussed. In particular, the radiative acceleration possibly builds up a dusty wall, which ‘shades’ the nucleus in edge-on views. This provides another version of the model for the formation of an obscuring torus.