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arXiv 1508.02571astro-ph.HE
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旋转黑洞周围平流吸积盘的质量损失

Mass loss from advective accretion disc around rotating black holes

Ramiz Aktar, Santabrata Das, Anuj Nandi

摘要:

我们研究了旋转黑洞周围平流吸积盘流出物质的性质。在吸积过程中,旋转的物质经历离心压力支持的激波跃迁,有效地在黑洞周围以激波后日冕(以下简称PSC)的形式产生了一个虚拟的屏障。由于冲击压缩,PSC变得热和致密,最终由于额外的热梯度力的存在而使流入的物质的一部分偏转为双极流出。在我们的方法中,我们研究的流出属性的流入参数,即比能量(${\mathcal E}$)和比角动量($λ$)考虑到现实的流出几何周围的旋转黑洞。我们发现黑洞的自旋($a_k$)对流出速率$R_{\dot m}$(流出和流入的质量流量比)起着重要的作用,特别是对于同一组流入参数,$R_{\dot m}$与$a_k$直接相关.结果表明,在较大的内流参数范围内,黑洞的吸积-抛射解是全局性的,且有、无外流参数空间(${\mathcal E}$,$λ$)的有效面积随黑洞自旋($a_k$)的增大而减小.我们计算了最大流出速率($R^{max}_{\dot m}$)作为黑洞自旋($a_k$)的函数,并观察到对于具有$1.5 \ge γ\ge 4/3$的绝热指数$(γ)$,$R^{max}_{\dot m}$弱依赖于$a_k$,该$a_k$位于流入速率的$\sim 10\%-18\%$范围内.我们提出了我们的方法的观测含义,同时研究基于黑洞吸积态的定常/持续喷流活动。我们讨论,我们的形式主义似乎有可能解释所观察到的喷流动能的几个银河系黑洞源(GBH)和活动星系核(AGN)。

英文摘要:

We examine the properties of the outflowing matter from an advective accretion disc around a spinning black hole. During accretion, rotating matter experiences centrifugal pressure supported shock transition that effectively produces a virtual barrier around the black hole in the form of post-shock corona (hereafter, PSC). Due to shock compression, PSC becomes hot and dense that eventually deflects a part of the inflowing matter as bipolar outflows because of the presence of extra thermal gradient force. In our approach, we study the outflow properties in terms of the inflow parameters, namely specific energy (${\mathcal E}$) and specific angular momentum ($λ$) considering the realistic outflow geometry around the rotating black holes. We find that spin of the black hole ($a_k$) plays an important role in deciding the outflow rate $R_{\dot m}$ (ratio of mass flux of outflow and inflow), in particular, $R_{\dot m}$ is directly correlated with $a_k$ for the same set of inflow parameters. It is found that a large range of the inflow parameters allows global accretion-ejection solutions and the effective area of the parameter space (${\mathcal E}$, $λ$) with and without outflow decreases with black hole spin ($a_k$). We compute the maximum outflow rate ($R^{max}_{\dot m}$) as function of black hole spin ($a_k$) and observe that $R^{max}_{\dot m}$ weakly depends on $a_k$ that lies in the range $\sim 10\%-18\%$ of the inflow rate for the adiabatic index $(γ)$ with $1.5 \ge γ\ge 4/3$. We present the observational implication of our approach while studying the steady/persistent Jet activities based on the accretion states of black holes. We discuss that our formalism seems to have the potential to explain the observed Jet kinetic power for several Galactic Black Hole sources (GBHs) and Active Galactic Nuclei (AGNs).

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