论文标题
追踪H2O Maser星系中的周环密集气
Tracing circumnuclear dense gas in H2O maser galaxies
论文作者
论文摘要
已经编制了30 H2O半乳乳层的Maser星系，其已发表的HCN（J = 1-0）和HCO+（J = 1-0）的观察结果已编译，以研究与H2O Maser发射的密集气体相关性。我们的样本数量超过了迄今为止研究的先前HCN样品的大小，这是第一个关于与密集的气体示踪剂HCO+可能关系的首次研究。我们发现归一化的H2O MASER发射光度（LH2O \ LCO）与归一化HCO+线光度（LHCO+ \ LCO）之间存在很强的相关性。此外，在LH2O \ LCO和标准化的HCN线光度（LHCN \ LCO）之间发现了弱相关性。在排除发光和超大型红外星系（U）LIRG源后，还研究了样品，并且上述相关性明显更强。我们表明，从HCN和HCO+分子获得的“密集气体”分数与Maser发射密切相关，尤其是对于正常IR光度的星系（LIR <10^11lsun），我们表明HCO+是比HCN更好的“密集气”痕迹。对这些具有较高过渡水平线的密集气体示踪剂的进一步系统研究对于探测大型物理条件以及准确确定Maser的发射如何与致密气体相互关联至关重要。
A sample of 30 H2O extra-galactic maser galaxies with their published HCN(J=1-0) and HCO+(J=1-0) observations has been compiled to investigate the dense gas correlation with H2O maser emission. Our sample number exceeds the size of the previous HCN samples studied so far by a factor of three, and it is the first study on the possible relation with the dense gas tracer HCO+. We find a strong correlation between normalized H2O maser emission luminosity (LH2O\LCO) and normalized HCO+ line luminosity (LHCO+\LCO). Moreover, a weak correlation has been found between LH2O\LCO and normalized HCN line luminosity (LHCN\LCO). The sample is also studied after excluding Luminous and Ultraluminous infrared galaxy (U)LIRG sources, and the mentioned correlations are noticeably stronger. We show that 'Dense gas' fractions as obtained from HCN and HCO+ molecules tightly correlate with maser emission, especially for galaxies with normal IR luminosity(LIR< 10^11Lsun) and we show that HCO+ is a better 'dense gas' tracer than HCN. Further systematic studies of these dense gas tracers with higher transition level lines are vital to probe megamaser physical conditions and to accurately determining how maser emission interrelates with the dense gas.
