恒星形成区GGD12-15的近红外观测

NIR Observations of the Star Forming Region GGD12-15

给出恒星形成区GGD12-15的宽波段JHK和窄波段H2 v=1-0 S(1)近红外成像观测.观测图像揭示了致密的年轻红外星团和与红外源成协的红外星云,并发现了以H2发射结表征的星团外流活动.大多数红外点源在光学波段不可见;对76颗红外点源的JHK’测光结果显示,有32颗具有红外超,其中5颗表现原恒星特征,表明分子云中的恒星形成活动很活跃.以B8光谱型作为大质量星分界,由色星等图估计出大质量星所占星团比例为-10％-26％.GGD12-15星团的K’星等分布的峰值位于15.0mag,并在13.0mag-16.0mag平坦分布;[H.K’]色分布的峰值出现在-0.7mag,在此以上更红的星团成分占70％.在GGD12-15区新发现的氢分子发射结集中在星团中心领域,其空间分布明显与剧烈的恒星形成活动相关;有5个发射结位于分子外流的中心区域,暗示其激发可能与分子外流同源.

Near infrared imaging of the star forming region GGD12-15 is presented with the JHK broad-band and H2 v=l-0 S(1) narrow-band filters. The images reveal the dense young cluster and nebulae associated with the cluster in the field, and uncover the cluster outflow activity by the H2 line knot emission. Most of the infrared point sources are invisible in optical. The photometry of 76 point sources displays 32 sources with infrared excess, in which five show characteristics of protostars, indicating strong star formation activity in the cloud. The color-magnitude diagram show a ratio of-10%-26% massive cluster members as outlined by B8 spectral type. The K' magnitude distribution has a flat distribution in 13.0mag-16.0mag, with the peak at 15.0mag. The [H-K'] color distribution has a peak at-0.7mag, and the redder cluster members take percentage of 70%. The H2 knots are observed around the central cluster, and the distribution show a strong relationship with the strong star formation activity. Five H2 knots are discovered in the central area of CO outflow, indicating the same powering source with the molecular outflow.