• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.232.2-232.2
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• 2012

Submillimeter Galaxies (SMGs) are high-redshift galaxies undergone extremely intense starbursts. Their UV radiation is heavily extinguished by dust and is re-radiated in the far-IR and submillimeter. They are thought to be progenitors of present-day giant elliptical galaxies and can be tracers of the highest density environment at high redshift. However, because of the low angular resolution of existing single-dish submillimeter telescopes, the progress in understanding the SMG population has been remarkably slow. In this talk, I will outline the outstanding issues in this field, and introduce our Submillimeter Array interferometric studies of SMGs. I will also discuss possible new research that will be enabled by next-generation instruments such as ALMA and LMT.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.27-27
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• 2013

Development of bolometer array and camera at millimeter and submillimeter wavelengths plays an important role for detecting submillimeter galaxies (SMGs) which appear to be very bright at the submillimeter and millimeter wavelengths. These SMGs, luminous infrared galaxies detected at mm/submm wavelengths seem to be progenitors of present-day massive galaxies and account for their considerable contributions to the light from the early universe and their expected high star formation rates (SFRs) if there is a close link between the SMG phenomena and the star formation activities and the interstellar dust in galaxies is mainly heated by the star light. In this talk, we review assembly of SMGs compiled with observations using the bolometer arrays and cameras and investigate their spectral energy distribution fits including the data at other wavelengths which trace the photometric properties and the red-shift distribution of galaxies. We find that these bright SMGs significantly contribute to the cosmic star formation rate density at red-shifts of 2-3 (about 8 %) for the spatial distribution of these galaxies.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.51.1-51.1
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• 2013

Submillimeter galaxies are the progenitors of massive galaxy formation, and therefore their interaction with the early intergalactic medium must be an important subject in the cosmology and galaxy astrophysics. However, their detailed relation between the galaxies and surrounding environments is still largely unknown. In this poster, we will present the characteristics of their surrounding environments of a large sample of mm-detected submillimeter galaxies. We will also discuss the proposal for the future observations of these galaxies and their environments using the ALMA and the GMT.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.74.3-74.3
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• 2019

SCUBA-2 North Ecliptic Pole survey, one of the ongoing JCMT large programs, is designed to obtain 850 ㎛ imaging data over ~4 deg² around the NEP based on the AKARI NEP-Wide survey. By August 2019, the program is 50 % complete in terms of observing time, increasing the submillimeter coverage by a factor of 2 with the comparable depth. The rms measured in the deepest center is 0.92 mJy/beam, slightly above the 850 ㎛ confusion limit. With 4 σ detection, the source count is 50 % complete at 9 mJy. The surface density of submillimeter galaxies at this flux limit is 200 deg^-2. Multi-wavelength identification of the 850 ㎛ sources was done through the likelihood analysis based on the far-infrared (250-500 ㎛), mid-infrared (18 ㎛), near-infrared (2-4 ㎛), and optical (i-band) source catalog. We are going to present morphologies and physical properties of 850 ㎛ selected submillimeter galaxies with the help of ancillary multi-wavelength datasets over the NEP area.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.38.1-38.1
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• 2010

We present the results of the survey for submillimeter galaxies in the MS0451 (04h 54m 10.8s, -03d 00m 57.0s) at z = 0.55 and PKS1138-262 (11h 40m 48.25s, -26d 29m 10.1s) at z = 2.16 with the 1.1mm bolometer array AzTEC at the James Clerk Maxwell Telescope. The samples were centered on a prominent large-scale structure overdensity. Submillimeter galaxies seem to be starburst galaxies at high redshift ($z\;\geq\;1$) with high starformation rates ($\sim1000M\odot\;yr^{-1}$) or active galactic nuclei (AGN). We have obtained AzTEC images using the AzTEC data reduction pipeline with the IDL language. Through a bayes' theorem, we determined the extragalaxy catalogue, containing the false-detection rate, completeness, flux deboosting correction, and the source positional uncertainty in this region. We compared the catalogue with HST, DSS, 2MASS observations.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.35.2-35.2
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• 2020

Submillimeter galaxies (SMGs) have played an important role in the understanding of galaxy evolution and cosmic star formation history at high redshift because they are known as being located at z ~ 2 and harbor a vigorous star formation. Therefore studying properties of SMGs can lead us to understand evolution of massive and actively star forming galaxies and distribution of cosmic star formation density. Recently we detected 548 SMGs near North Ecliptic Pole with JCMT/SCUBA-2 from the JCMT large program covering about 2 deg2 so far. To derive their physical parameters, we compiled a multi-wavelength photometry ranging from optical (0.3 ㎛) to submillimeter (850 ㎛) by cross-identifying counterparts at different wavelengths. In order to find counterparts, we used either VLA-1.4 GHz image and/or Spitzer/IRAC 3.6 ㎛, 4.5 ㎛ image. The number of SMGs with relatively robust counterparts is 349. In this talk, we present photometric redshifts, stellar mass, star formation rates, total infrared luminosity, and AGN fraction of these 349 SMGs derived through SED fitting analysis.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.74.3-74.3
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• 2017

Considering the statistical redshift distribution of the known submillimeter galaxy (SMG) population, most of the significant optical emission lines such as [OII]${\lambda}3727$, $H{\beta}$, [OIII]${\lambda}5007$, and $H{\alpha}$ are redshifted into near-infrared. Using the 3D-HST grism data that provides low resolution NIR spectroscopy over the several deep fields covered by the JCMT large program S2CLS, I investigated the properties of the optical emission lines for submm galaxies which could be used as a proxy for future optical/NIR identification and follow up of the SMGs.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.179-183
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• 2017

AKARI and the subsequent Herschel Space Observatory have yielded tremendous advancement in our knowledge of the infrared-submillimeter properties of active galaxies and active galactic nuclei, AGN. This short review describes some highlights. Active galaxies are found to do what they are supposed to do: build up their stellar bodies while building up their central black holes.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.39.3-39.3
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• 2019

Ram pressure stripping due to the intracluster medium (ICM) is an important environmental process, which causes star formation quenching by effectively removing cold interstellar gas from galaxies in dense environments. The evidence of diffuse atomic gas stripping has been reported in several HI imaging studies. However, it is still under debate whether molecular gas (i.e., a more direct ingredient for star formation) can be also affected and/or stripped by ram pressure. The goal of this thesis is to understand the impact of ram pressure on the molecular gas content of cluster galaxies and hence star formation activity. To achieve this, we conducted a series of detailed studies on the molecular gas properties of three Virgo spiral galaxies with clear signs of active HI gas stripping (NGC 4330, NGC 4402, and NGC 4522) based on high-resolution CO data obtained from the Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA). As a result, we find the evidence that the molecular gas disk also gets affected by ram pressure in similar ways as HI even well inside of the stellar disk. In addition, we detected extraplanar 13CO clumps in one of the sample, which is the first case ever reported in ram pressure stripped galaxies. By analyzing multi-wavelength data (e.g., Hα, UV, HI, and CO), we discuss detailed processes of how ram pressure affects star formation activities and hence evolution of cluster galaxies. We also discuss the origin of extraplanar 13CO, and how ram pressure can potentially contribute to the chemical evolution of the ICM.

• Journal of The Korean Astronomical Society
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• v.36 no.3
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• pp.149-158
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• 2003

Deep surveys at mid-infared through submillimeter wavelengths indicate that a substantial fraction of the total luminosity output from galaxies at high redshift (z > 1) emerges at wavelengths 30 - 300${\mu}m$. In addition, much of the star formation and AGN activity associated with galaxy building at these epochs appears to reside in a class of luminous infrared galaxies (LIGs), often so heavily enshrouded in dust that they appear as 'blank-fields' in deep optical/UV surveys. Here we present an update on the state of our current knowledge of the cosmic evolution of LIGs from z = 0 to z $\~$ 4 based on the most recent data obtained from ongoing ground-based redshift surveys of sources detected in ISO and SCUBA deep fields. A scenario for the origin and evolution of LIGs in the local Universe (z < 0.3), based on results from multiwavelength observations of several large complete samples of luminous IRAS galaxies, is then discussed.