Name:	Izumi, Natsuko
Email:	izumi@ioa.s.u-tokyo.ac.jp
Institution:	University of Tokyo
Title:	Search for star-forming regions in the extreme outer Galaxy with WISE data
Topic:	Discoveries
Abstract:	The extreme outer Galaxy (EOG), defined as the region with Galactocentric radius RG ≥ 18 kpc (e.g., Kobayashi et al. 2008) has a very different environment from the solar neighborhood with a much lower gas densities, lower metallicity, and little or no perturbation from the spiral arms. Because such environments may have similar characteristics that existed in the early phase of Galaxy formation, we might be able to directly observe the galaxy formation processes in unprecedented detail at a much closer distance than distant galaxies. In past studies, few dozens of molecular clouds in the EOG were discovered by some outer Galaxy surveys (Digel et al. 1994; Heyer et al. 1998). We are searching for star-forming regions associated with the molecular clouds to comprehensively study star formation activities in the EOG. So far, we found two embedded clusters in the two brightest clouds by high-resolution 12CO observation with Nobeyama 45 m telescope and deep near-infrared imaging with Subaru 8.2 m telescope, and confirmed that these clusters are also clearly identified as groups of compact reddened stellar objects in WISE mid-infrared images (Izumi et al. 2014). We also searched for star-forming regions in the other molecular clouds in the EOG using WISE data, to find many new candidate star-forming regions. With the unprecedented high sensitivity, WISE is very powerful to detect distant star-forming regions, and enable us the statistical study of star formation in the EOG for the first time.