论文标题
Galactic Center IRS 13E3距Sagittarius A $^{\ ast} $实际上有多远？
How far actually is the Galactic Center IRS 13E3 from Sagittarius A$^{\ast}$?
论文作者
论文摘要
银河中心IRS 13E群集是一个非常有趣的IR对象，位于sagittarius a $^\ ast $（sgr a $^\ ast $）的$ \ sim0.13 $ pc中。既有存在的论点，也反对这样的假设，即集群中存在像中间质量黑洞（IMBH）这样的黑质量。最近，我们在使用ALMA的H30 $α$重组线中检测到属于群集的IRS 13E3周围的旋转离子化气环。封闭的质量得出为$ m _ {\ mathrm {ectl。}} \ simeq2 \ times10^4 $ $ $ m_ \ odot $，它与IMBH一致，几乎比Sgr a $^a $^ast $的IMBH的Astrometrotic上限质量少。由于极限质量取决于距SGR A $^\ ast $的真实三隔离（3D）距离，因此在观察中确定它非常重要。但是，3D距离是不确定的，因为很难通过通常的方法来确定视线（LOS）距离。我们将尝试通过光谱信息来估算LOS距离。 Ch $ _3 $ OH分子在SGR周围a $^{\ ast} $围绕宇宙射线很容易破坏。但是，我们在与IRS 13E3相关的电离气流中检测到了非常激发的CH $ _3 $ OH排放线。这表明IRS 13E3位于$ r \ gtrsim 0.4 $ PC，来自SGR A $^{\ ast} $。
The Galactic Center IRS 13E cluster is a very intriguing IR object located at $\sim0.13$ pc from Sagittarius A$^\ast$ (Sgr A$^\ast$) in projection distance. There are both arguments for and against the hypothesis that a dark mass like an intermediate mass black hole (IMBH) exists in the cluster. Recently we have detected the rotating ionized gas ring around IRS 13E3, which belongs to the cluster, in the H30$α$ recombination line using ALMA. The enclosed mass is derived to be $M_{\mathrm{encl.}}\simeq2\times10^4$ $M_\odot$, which agrees with an IMBH and is barely less than the astrometric upper limit mass of the IMBH around Sgr A$^\ast$. Because the limit mass depends on the true three-deminsional (3D) distance from Sgr A$^\ast$, it is very important to determine it observationally. However, the 3D distance is indefinite because it is hard to determine the line-of-sight (LOS) distance by usual methods. We would attempt to estimate the LOS distance by spectroscopic informations. The CH$_3$OH molecule is easily destroyed by cosmic ray around Sgr A$^{\ast}$. However, we detected a highly excited CH$_3$OH emission line in the ionized gas stream associated with IRS 13E3. This indicates that IRS 13E3 is located at $r\gtrsim 0.4$ pc from Sgr A$^{\ast}$.
