arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2101.07583astro-ph.HE
收藏

黑洞双星光谱中次均分磁场的观测特征

An Observational Signature of Sub-Equipartition Magnetic Fields in the Spectra of Black Hole Binaries

John Wallace, Asaf Pe'er

摘要:

在吸积盘的研究中,一个常见的假设是磁能密度和动能密度应均分。该假设依赖于磁场强度相对于流中颗粒的动能的更快增长速率,对于减小的半径,结合倾向于均分的耗散机制。在本文中,我们通过模拟几个黑洞双星在静止状态下的射电、毫米波和光谱来检验这一假设。我们使用一个标准的两个组件磁盘模型,包括一个内部的几何厚和光学薄的磁盘,发射热同步辐射,以及一个外部,薄磁盘,辐射作为一个黑体。我们发现,在低吸积率典型的静态,光谱形状是定性再现使用磁场之间的0.1%和1%的均分值,大大小于以前认为的。我们讨论了我们的发现,鉴于(1)在这些对象中的射流的发射,这通常被认为是依赖于在磁盘的中心区域的强磁场的存在;和(2)磁耗散的流入结构中的作用。

英文摘要:

A common assumption used in the study of accretion disks is that the magnetic energy density and the kinetic energy density should be in equipartition. This assumption relies on the faster growth rate of the magnetic field strength against the kinetic energy of the particles in the flow, for decreasing radius, combined with a dissipation mechanism that tends towards equipartition. In this paper, we examine this assumption by modeling the radio, mm and optical spectra of several black hole binaries in their quiescent state. We use a standard two-component disk model, consisting of an inner geometrically thick and optically thin disk, emitting thermal synchrotron radiation, along with an outer, thin disk, which radiates as a multicolor blackbody. We find that at the low accretion rates typical of the quiescent state, the spectral shape is qualitatively reproduced using magnetic fields that are between 0.1% and 1% of the equipartition value, considerably smaller than previously thought. We discuss our findings in view of (1) the launching of jets in these objects, which is commonly believed to rely on the presence of a strong magnetic field in the central region of the disk; and (2) the role of magnetic dissipation in the structure of the inflow.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑