We present the analysis of Spitzer/IRAC and near infrared imaging obser- vation of AFGL 5157, an active star forming region. In the IRAC images, this region shows strong emissions of polycyclic aromatic hydrocarbons i...We present the analysis of Spitzer/IRAC and near infrared imaging obser- vation of AFGL 5157, an active star forming region. In the IRAC images, this region shows strong emissions of polycyclic aromatic hydrocarbons in channel 4 and emis- sions of H2 in channel 2. Many of the H2 features are aligned to form jet-like struc- tures. Three bipolar jets in the NHa core region and a couple of jets northwest of the core have been identified. We identify the possible driving agents of the bipolar jets and show them to be very young. An embedded cluster has been detected in the NH3 core; many members in the cluster have spectral energy distributions that increase from JHK bands toward longer wavelengths, indicative of their early evolutionary stages. Millimeter and submillimeter continuum emissions in the NH3 core and the northwest subregion are found to coincide spatially with these presumable Class0/I sources. The existence of H2 bipolar jets and very young stellar objects suggests that star formation is continuing at the present epoch in these subregions. Combining in- formation from previous studies, we propose a sequential star formation scenario in the whole AFGL 5157 region.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 10873037 and 10921063)partially supported by the National Basic Research Program of China (973 Program, 2007CB815406)
文摘We present the analysis of Spitzer/IRAC and near infrared imaging obser- vation of AFGL 5157, an active star forming region. In the IRAC images, this region shows strong emissions of polycyclic aromatic hydrocarbons in channel 4 and emis- sions of H2 in channel 2. Many of the H2 features are aligned to form jet-like struc- tures. Three bipolar jets in the NHa core region and a couple of jets northwest of the core have been identified. We identify the possible driving agents of the bipolar jets and show them to be very young. An embedded cluster has been detected in the NH3 core; many members in the cluster have spectral energy distributions that increase from JHK bands toward longer wavelengths, indicative of their early evolutionary stages. Millimeter and submillimeter continuum emissions in the NH3 core and the northwest subregion are found to coincide spatially with these presumable Class0/I sources. The existence of H2 bipolar jets and very young stellar objects suggests that star formation is continuing at the present epoch in these subregions. Combining in- formation from previous studies, we propose a sequential star formation scenario in the whole AFGL 5157 region.
