We carry out the study of 850 μm sources in a part of the XMM-LSS field. The 850 μm imaging data were obtained by the SCUBA-2 on the James Clerk Maxwell Telescope (JCMT) for three days in July 2015 with an integration time of 6.1 hours, covering a circular area with a radius of 15′. We choose the central area up to a radius of 9.′15 for the study, where the noise distribution is relatively uniform. The root mean square (rms) noise at the center is 2.7 mJy. We identify 17 sources with S/N > 3.5. Differential number count is estimated in flux range between 3.5 and 9.0 mJy after applying various corrections derived by imaging simulations, which is consistent with previous studies. For detailed study on the individual sources, we select three sources with more reliable measurements (S/N > 4.5), and construct their spectral energy distributions (SEDs) from optical to far-infrared band. Redshift distribution of the sources ranges from 0.36 to 3.28, and their physical parameters are extracted using MAGPHYS model, which yield infrared luminosity LIR = 1011.3−1013.4 L⊙, star formation rate SFR = 101.3−103.2 M⊙yr−1 and dust temperature TD = 30−53 K. We investigate the correlation between LIR and TD, which appears to be consistent with previous studies.

We present an optical imaging survey of AKARI Deep Field South (ADF-S) using the Korea Microlensing Telescope Network (KMTNet), to find optical counterparts of dusty star-forming galaxies. The ADF-S is a deep far-infrared imaging survey region with AKARI covering around 12 deg2, where the deep optical imaging data are not yet available. By utilizing the wide-field capability of the KMTNet telescopes (∼4 deg2), we obtain optical images in B, R and I bands for three regions. The target depth of images in B, R and I bands is 24 mag (AB) at 5, which enables us to detect most dusty star-forming galaxies discovered by AKARI in the ADF-S. Those optical datasets will be helpful to constrain optical spectral energy distributions as well as to identify rare types of dusty star-forming galaxies such as dustobscured galaxy, sub-millimeter galaxy at high redshift.

A large-scale neutral hydrogen (H i) ring serendipitously found in the Leo I galaxy group is 200 kpc in diameter with MHi ~ 1:67 X 109M⊙, unique in size in the Local Universe. It is still under debate where this Hi ring originated - whether it has formed out of the gas remaining after the formation of a galaxy group (primordial origin) or been stripped during galaxy-galaxy interactions (tidal origin). We are investigating the optical and Hi gas properties of the dwarf galaxies located within the gas ring in order to probe its formation mechanism. In this work, we present the photometric properties of the dwarfs inside the ring using the CFHT MegaCam u*, g', r' and i'-band data. We discuss the origin of the gas ring based on the stellar age and metal abundance of dwarf galaxies contained within it.