Stellar Populations in Spiral Galaxies

旋涡星系中的恒星种群*星系的演化是一个令人兴奋的课题，主要是因为当星系还很年轻的时候，我们建造强大仪器来观测远距离的能力越来越强，但也因为我们对它们的内容了解得更多。然而，星系组件的组装和演化仍然没有被很好地理解。恒星群很好地跟踪了一个星系随着时间的推移所经历的变化。因此，这里建议使用它们来洞察驱动恒星形成和星系演化的不同机制。这项研究计划将包括梅根蒂山天文台和加拿大-法国-夏威夷望远镜的最新最先进的天文仪器SPIOMM和SITELLE，以便以高空间分辨率同时获得附近星系整个表面上每个区域的可见光光谱。在这些数据立方体中看到的发射线和吸收线将使用演化恒星群合成模型和辐射转移代码进行分析，以表征星系组件的年龄、化学成分和质量。一种分离光谱中重叠的不同群体的签名的技术将被改进。应特别注意污染成分光谱指示器的扩散电离气体。这种气体的来源还没有很好地确定，但现在用这些新仪器研究变得更容易了。年轻的恒星爆发区域也将利用其众多的OB恒星产生的紫外线通量和紫外线成像望远镜(将于2015年发射)的数据进行分析。UVIT将非常有用地将恒星爆发的紫外线特性和形态与SPIOMM和SITELLE的可见光地面数据进行比较。所有这些仪器所提供的高空间分辨率对于在不同成分性质之间建立联系将是独一无二的，例如用来测量通过银河盘的化学丰度梯度。为了了解影响恒星形成和星系演化的不同机制，正在设计SITELLE和UVIT调查，其中包括附近具有不同性质(条形、相互作用、质量)的螺旋星系。随着新一代大型望远镜的问世，该计划正在为研究更远距离的星系准备工具和确定方向。**

STELLAR POPULATIONS IN SPIRAL GALAXIES***The evolution of galaxies is an exciting subject, mainly because or our increasing capabilities to build powerful instruments to look at large distances when galaxies were much younger, but also because we understand more about their content. Nevertheless, the assemblage and evolution of galaxy components is still not well understood. Stellar populations are good tracers of the change experienced by a galaxy over time. It is therefore proposed here to use them to gain insights into the different mechanisms that drive star formation and galaxy evolution. This research program will include SpIOMM and SITELLE, new state of the art astronomical instruments at the Observatoire du Mont-Mégantic and Canada-France-Hawaii Telescope, to obtain simultaneously spectra in the visible for every region on the whole surface of a nearby galaxy with a high spatial resolution. Emission and absorption lines seen in these datacubes will be analysed using evolutionary stellar population synthesis models and radiative transfer codes to characterize the age, chemical composition, and mass of the galaxy components. A technique to separate the signatures of the different populations that overlap in a spectrum is to be refined. A special attention is to be given to the diffused ionized gas that is contaminating the component spectral indicators. The origin of this gas is not well established yet, but becomes easier to study now with these new instruments. Young starburst regions will also be analyzed using the ultraviolet flux produced by their numerous OB stars with data from the Ultraviolet Imaging Telescope (to be launched in 2015). UVIT will be extremely useful to compare the starburst ultraviolet properties and morphology with the visible ground-based data from SpIOMM and SITELLE. The high spatial resolution offered by all these instruments will be unique to establish links between the different component properties, for example to measure chemical abundance gradients through the galactic disks. SITELLE and UVIT surveys are being designed which include nearby spiral galaxies with different properties (bar, interactions, mass) in order to understand the different mechanisms that are influencing star formation and galaxy evolution. This program is preparing the tools and setting the orientation for the study of galaxies at larger distances with the new generation of large telescopes to come.**