标题： 从紫外到红外探索局部星形成ULIRG的物理性质 显示英文标题

标题： Exploring the physical properties of local star-forming ULIRGs from the ultraviolet to the infrared

摘要： 我们应用了da Cunha、Charlot和Elbaz（2008）提出的从紫外到远红外波段星系谱能量分布（SEDs）的模型，研究了一组纯粹由恒星形成驱动的超亮红外星系（ULIRGs）的小型试点样本。 我们使用这一基于物理动机的模型来解释16个ULIRGs的观测SEDs，该模型考虑了恒星群体从紫外到近红外的发射以及尘埃在两个成分中的消光：一个光学厚的恒星爆发成分和弥漫的星际介质（ISM）。 红外发射通过假设这些成分中被尘埃吸收的所有能量都会在中红外和远红外波长重新辐射而计算得出。 此模型使我们能够统计推导出包括恒星形成率、恒星质量以及不同尘埃组分的温度和质量，以及可能的恒星形成历史在内的物理属性。 我们发现，尽管紫外到近红外的发射仅占ULIRGs总辐射功率的一小部分，但在这个波长范围内进行观测对于理解这些星系弥散星际介质中的恒星群体和尘埃消光性质非常重要。 此外，我们的分析表明，使用斯皮策空间望远镜红外分光仪的中红外光谱对于获得中央能源源的消光的现实估计至关重要，主要是通过9.7微米硅酸盐特征的深度，并因此准确约束总能量平衡。 我们的发现与当地宇宙中ULIRGs的物理特性从根本上不同于低红外亮度星系的观念一致，并且当地ULIRGs是合并引发的恒星爆发的结果。 显示英文摘要

摘要： We present an application of the da Cunha, Charlot & Elbaz (2008) model of the spectral energy distribution (SEDs) of galaxies from the ultraviolet to far-infrared to a small pilot sample of purely star-forming Ultra-Luminous Infrared Galaxies (ULIRGs). We interpret the observed SEDs of 16 ULIRGs using this physically-motivated model which accounts for the emission of stellar populations from the ultraviolet to the near-infrared and for the attenuation by dust in two components: an optically-thick starburst component and the diffuse ISM. The infrared emission is computed by assuming that all the energy absorbed by dust in these components is re-radiated at mid- and far-infrared wavelengths. This model allows us to derive statistically physical properties including star formation rates, stellar masses, as well as temperatures and masses of different dust components and plausible star formation histories. We find that, although the ultraviolet to near-infrared emission represents only a small fraction of the total power radiated by ULIRGs, observations in this wavelength range are important to understand the properties of the stellar populations and dust attenuation in the diffuse ISM of these galaxies. Furthermore, our analysis indicates that the use of mid-infrared spectroscopy from the Infrared Spectrograph on the Spitzer Space Telescope is crucial to obtain realistic estimates of the extinction to the central energy source, mainly via the depth of the 9.7-micron silicate feature, and thus accurately constrain the total energy balance. Our findings are consistent with the notion that, in the local Universe, the physical properties of ULIRGs are fundamentally different from those of galaxies with lower infrared luminosities and that local ULIRGs are the result of merger-induced starbursts. [abridged]