We present deep (250 ks) Chandra observations of the nearby galaxy group NGC 1600, which has at its centre an ultramassive black hole (17 ± 1.5 billion M⊙). The exceptionally large mass of the black hole coupled with its low redshift makes it one of only a handful of black holes for which spatially resolved temperature and density profiles can be obtained within the Bondi radius with the high spatial resolution of Chandra. We analysed the hot gas properties within the Bondi accretion radius R$_{\mbox{B}}=1.2\!-\!1.7\:\mathrm{ arcsec}= 0.38\!-\!0.54 \,{\mbox{kpc}}$. Within a ∼3 kpc radius, we find two temperature components with statistical significance. Both the single-temperature and two-temperature models show only a very slight rise in temperature towards the centre, and are consistent with being flat. This is in contrast with the expectation from Bondi accretion for a temperature profile which increases towards the centre, and appears to indicate that the dynamics of the gas are not being determined by the central black hole. The density profile follows a relatively shallow ρ ∝ r−[0.61 ± 0.13] relationship within the Bondi radius, which suggests that the true accretion rate on to the black hole may be lower than the classical Bondi accretion rate.

中文翻译：

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在 NGC 1600 超大质量黑洞的邦迪半径内探测

我们展示了对附近星系群 NGC 1600 的深度（250 ks）钱德拉观测，其中心有一个超大质量黑洞（17 ± 15 亿 M⊙）。黑洞的超大质量加上其低红移使其成为少数几个可以在邦迪半径内以钱德拉的高空间分辨率获得空间分辨温度和密度分布的黑洞之一。我们分析了邦迪吸积半径 R$_{\mbox{B}}=1.2\!-\!1.7\:\mathrm{ arcsec}= 0.38\!-\!0.54\,{\mbox{ kpc}}$。在~3 kpc 半径内，我们发现两个具有统计意义的温度分量。单温度模型和双温度模型都显示出向中心的温度只有非常轻微的上升，并且与平坦一致。这与邦迪吸积对向中心增加的温度分布的预期相反，并且似乎表明气体的动力学不是由中心黑洞决定的。密度分布在邦迪半径内遵循相对较浅的 ρ ∝ r-[0.61 ± 0.13] 关系，这表明黑洞的真实吸积率可能低于经典的邦迪吸积率。