标题： 斯皮策对深深遮蔽的星系核的观测 显示英文标题

标题： Spitzer Observations of Deeply Obscured Galactic Nuclei

摘要： 我们报告了使用斯皮策空间望远镜上的红外光谱仪（IRS）对一批深深遮蔽的ULIRG核样本中的星际介质特征进行中红外光谱研究的初步成果。 光谱极其丰富且复杂，揭示了无定形和晶体硅酸盐、脂肪烃、水冰以及热CO气体、温暖C_2H_2、HCN和CO_2气相带的吸收特征。 发现PAH发射带通常较弱，在某些情况下甚至缺失。 这些特征正在探测一个密集且温暖的环境，在其中晶体硅酸盐和水冰能够存活，但挥发性冰（在银河系密集分子云中通常被检测到）则无法存在。 如果主要由恒星形成驱动，则气体和尘埃的密度及条件必须极为极端，才不会引发通常与星暴相关的发射特征。 显示英文摘要

摘要： We report on our first results from a mid-infrared spectroscopic study of ISM features in a sample of deeply obscured ULIRG nuclei using the InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. The spectra are extremely rich and complex, revealing absorption features of both amorphous and crystalline silicates, aliphatic hydrocarbons, water ice and gas phase bands of hot CO and warm C_2H_2, HCN and CO_2. PAH emission bands were found to be generally weak and in some cases absent. The features are probing a dense and warm environment in which crystalline silicates and water ice are able to survive but volatile ices, commonly detected in Galactic dense molecular clouds, cannot. If powered largely by star formation, the stellar density and conditions of the gas and dust have to be extreme not to give rise to the commonly detected emission features associated with starburst.