Search for Wolf-Rayet Stars in Massive Star Clusters

为了研究大质量星团的形成、演化过程和年龄，以及对星际介质的分布和贡献，我们进行了近红外光谱成像观测。观测使用了专为探测大质量恒星而定制的近红外窄带滤光片(例如1.875um，2.07um)和宽带滤光片(Ks)。在大质量星团中，存在着许多类型的大质量恒星，即Wolf-Rayet恒星，它们似乎是Ib/c型超新星、发光蓝变星(LBV)、黄超巨星(YHG)、红超巨星(RSG)等的祖先。从这些近红外滤光片得到的颜色-颜色图为我们提供了灰尘使物体变红的颜色信息。因此，该图不仅对于探测发射恒星是有效的，而且对于理解大质量恒星从诞生到终结的各个演化阶段也是有效的。

In order to investigate not only the formation, evolution process, and age of massive star clusters but also distribution and contribution to interstellar medium, we had carried out near-infrared spectroscopic imaging observation. NIR narrow-band filters (ex; 1.875um, 2.07um) which is customized for detection of massive stars and broad-band filter (Ks) are used for the observation. In the massive star clusters, many type of massive stars exist ; that is, Wolf-Rayet stars which are seemed to be the progenitors of Ib/c type supernovae, Luminous Blue Variable (LBV), Yellow Hyper Giant (YHG), Red Super GIant (RSG), and so on. The color-color diagram that is derived from these NIR filters gives us color information of reddening object by dust. Therefore the diagram is effective for not only detection of emission stars but also understanding of various stage of evolution from birth to end for massive stars.