论文标题
不平等的超级大质量黑洞二进制死亡的闪亮死亡
A Shining Death of Unequal Supermassive Black Hole Binaries
论文作者
论文摘要
在$λ$ CDM的情况下，小星系合并以生产较大的实体。由于在各种尺寸的星系中发现了超大质黑洞（SMBH），因此通常希望在星系合并期间形成SMBH二进制文件（SMBHB）。目前尚不清楚这些二进制文件最终可以合并，但普遍的共识是，轨道衰变是由周围的气体和恒星介导的。在这封信中，我们表明，在活跃的银河nulcei（AGNS）中，辐射场还会导致积聚SMBH的轨道收缩。相应的机制被称为“ poynting-robertson drag”（PR拖动），对明确定义的时间表$ ct _ {\ rm sal} $生效，其中$ t _ {\ rm sal} $是Agn的Salpeter Pisecale $ c =4ξ^{ - 1}ε^{ - 1} q^{1/3}（1+q）^{2/3}（1-ε）$是由辐射效率$ε$，质量比$ q $ q $ q的质量比q $确定的，两个黑孔的质量比q $ q $ q $ q $ q $ q $ q $ q $ q $ q $ q $ q yes $ q $ quartion $ξ$表征了blecrecretiion accecretion discrectary coccrethary coccorcysonkond。我们发现，当$ q \ lyssim $少数$ \ times10^{ - 5} $时，PR阻力比许多其他机制（例如动态摩擦和I型迁移）更有效地收缩二进制。我们的发现指出了不平等SMBHB的合并的新渠道以及AGN中中等大质量黑洞的清除。
In the $Λ$CDM scenario, small galaxies merge to produce larger entities. Since supermassive black holes (SMBHs) are found in galaxies of all sizes, SMBH binaries (SMBHBs) are generally expected to form during the amalgamation of galaxies. It is unclear what fraction of these binaries could eventually merge, but a general consensus is that initially the orbital decay is mediated by the surrounding gas and stars. In this Letter, we show that in active galactic nulcei (AGNs) the radiation field also causes the orbits of the accreting SMBHs to shrink. The corresponding mechanism, known as the "Poynting-Robertson drag" (PR drag), takes effect on a well-defined timescale $CT_{\rm Sal}$, where $T_{\rm Sal}$ is the Salpeter timescale of the AGN, presumably coincide with the primary SMBH, and $C=4ξ^{-1}ε^{-1}q^{1/3}(1+q)^{2/3}(1-ε)$ is a constant determined by the radiative efficiency $ε$, the mass ratio $q$ of the two black holes, and a parameter $ξ$ characterizing the size of the circum-secondary accretion disk. We find that when $q\lesssim$a few$\times10^{-5}$, the PR drag is more efficient in shrinking the binary than many other mechanisms, such as dynamical friction and type-I migration. Our finding points to a possible new channel for the coalescence of unequal SMBHBs and the clearing of intermediate-massive black holes in AGNs.
