Constraints on Galactic intermediate mass black holes
Constraints on Galactic intermediate mass black holes
复制标题
DOI：
10.1111/j.1365-2966.2006.10201.x
复制
发表时间：
2006-02
影响因子：
4.8
通讯作者：
M. Mapelli;A. Ferrara;N. Rea;Sissa;SRON-Utrecht
中科院分区：
文献类型：
--
作者：
M. Mapelli;A. Ferrara;N. Rea;Sissa;SRON-Utrecht
中等质量黑洞(IMBH；101.3−5M⊙)被认为是第三族恒星的遗迹，或者是年轻星团中恒星失控坍塌的产物；它们的数量和存在与否尚不确定。我们运行了银河系IMBH的N体模拟，将它们模拟为根据Navarro，Frenk&White(NFW)或更集中的Diemand，Madau&Moore(DMM)密度分布的晕群。当IMBH穿过银河系分子/原子氢区时，它们会吸积气体，从而成为X射线源。通过比较模拟X射线源和观测X射线源的分布，我们限制了银河系IMBH的密度。从银河系超发光X射线源的零探测，以及与IBIS/ISGRI星表中不明来源的模拟比较，我们发现了一个很强的上限·�10−2b(�10−1b)，如果IMBH通过ADAF盘聚集的话。如果IMBH以更高的效率成生，例如通过形成薄吸积盘，则可以得到略强的约束(·�10−3b对于DMM剖面；·�10−2b对于NFW剖面)。虽然不是很严格，但这种限制是迄今为止文献中派生出的最严格的限制。
Intermediate Mass Black Holes (IMBHs; 10 1.3−5 M⊙) are thought to form as relics of Population III stars or from the runaway collapse of stars in young clusters; their number and very existence are uncertain. We ran N-body simulations of Galactic IMBHs, modelling them as a halo population distributed according to a Navarro, Frenk & White (NFW) or a more concentrated Diemand, Madau & Moore (DMM) density profile. As IMBHs pass through Galactic molecular/atomic hydrogen regions, they accrete gas, thus becoming X-ray sources. We constrain the density of Galactic IMBHs, •, by comparing the distribution of simulated X-ray sources with the observed one. From the null detections of Milky Way Ultra-Luminous X-ray sources, and from a comparison of simulations with unidentified sources in the IBIS/ISGRI catalogue we find a strong upper limit • � 10 −2 b(� 10 −1 b) for a DMM (NFW) profile, if IMBHs accrete via ADAF disks. Slightly stronger constraints (• � 10 −3 b for a DMM profile; • � 10 −2 b for a NFW profile) can be derived if IMBHs accrete with higher efficiency, such as by forming thin accretion disks. Although not very tight, such constraints are the most stringent ones derived so far in the literature.