水脉泽寄主活动星系核的吸积率(英文)

On the Accretion Rates of Host AGN of H_2O Masers

水超脉泽辐射( 各向同性光度超过 10 个太阳光度) 通常在星系中心最内部的核区( 小于几个秒差距) 被发现,因而活动星系核被认为是其唯一的能量源。同其它没有检测到水脉泽辐射的活动星系核相比,水脉泽寄主活动星系核可能隐含着某种或某些特殊性质。基于此我们调研了已经公开发表的所有水脉泽源的 X 射线观测情况,得到了一个有 X 射线观测研究结果的子样本( 39 个源) 。由它们的 X 射线光度以及估算的黑洞质量,导出了它们的无量纲吸积率( logL2-10keV /LEdd,其中 L2-10keV和 LEdd分别是 2 - 10keV 的固有光度和爱丁顿光度) ; 与距离范围相当的、没有检测到水脉泽的活动星系核样本相比,发现脉泽寄主活动星系核有较高的吸积率。进一步分析比较这两个活动星系核样本的质量吸积率,也发现类似的趋势。此外,为了探索吸积率和水脉泽辐射间可能的内在联系,我们对它们的脉泽光度和吸积率进行了统计分析,然而结果显示二者之间没有明显的相关性。

Extragalactic H2O megamasers（Lmaser 〉10 L⊙） are typically found within the innermost regions of a few parsecs of galaxy centers and the Active Galactic Nuclei（AGN） are considered to be their ultimate energy sources.The host AGN of H2O masers may have some intrinsic properties not present in AGN without detected maser emission.For the purpose of finding these unique properties,we investigate all published nuclear maser sources and assemble a sample of 39 such sources with available observed X-ray data.Their dimensionless accretion rates（logL2-10keV /LEdd with L2-10keV and LEdd for the intrinsic 2-10keV X-ray luminosities and Eddington luminosities,respectively） are derived based on their X-ray data and our estimated mass values of the nuclear engines.We compare the results to the dimensionless accretion rates of a complete non-maser AGN sample at similar distances.The comparison shows that host AGN of H2O masers tend to have higher dimensionless accretion rates.We also calculate the mass accretion rates for both samples.A similar trend appears,i.e.,AGN with masers have higher accretion rates,which needs to be checked with a future larger sample.We further investigate possible connections between the accretion rates（both mass and dimensionless accretion rates） and H2O maser emission luminosities.We do not find any significant correlation between accretion rates and isotropic maser luminosities.