• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.80.1-80.1
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• 2010

From the Akari observational data, we have cross-identified a major portion of AGB stars listed in the catalog of AGB stars presented by Suh & Kwon (2009). We have used the Akari-IRC (Infrared Camera) PSC (Point Source Catalogue; about 850,000 sources at 9 and $18\;{\mu}m$) and Akari-FIS (Far-infrared Surveyer) BSC (Bright Source Catalogue; about 440,000 sources at 65, 90, 140 and $160\;{\mu}m$) as well as the IRAS and NIR observational data to make various meaningful two-color diagrams for AGB stars. We compare them with the theoretical models with various dust shell model parameters and chemical compositions.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.77.1-77.1
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• 2010

I summarize highlights from extragalactic research activities performed with AKARI infrared space telescope. The main emphasis will be given to the works carried out by Korean astronomers. The activities span a wide range of topics, such as MIR properties of nearby galaxies in cluster environment, MIR diagnosis of star-forming galaxies at z=0 through z=2 in the North Ecliptic Pole (NEP) survey field, the Extended Groth Strip (EGS), and the First Look Survey (FLS) field, and the NIR spectroscopy of Luminous Infrared Galaxies (LIRGs) and Active Galactic Nuclei/Super-massive Black Holes at low redshift as well as near the re-ionization epoch of z~6. I describe FIR and MIR all sky data which can be used as a precious resource for extragalactic research, and other future and ongoing works with AKARI. These AKARI results will form a strong basis for future studies using other facilities, such as infrared surveys with UKIRT, FIR study of dusty universe with Herschel, and the SPICA mission.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.66.2-66.2
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• 2010

별 탄생 초기 진화 단계에 있는 원시항성들은 별 주변 물질들에 의해 둘러싸여 있고, 낮은 온도로 인해 대부분의 에너지를 원적외선 영역에서 방출한다. 그러므로, 원시항성 진화 연구에서 진화단계와 물리적 특성을 바르게 유도하기 위해서는 원적외선 관측이 필수적이다. 본 연구는 원적외선 자료의 중요성을 정량적으로 보이기 위하여 이미 c2d 스피처 레거시 팀에서 동정한 원시성 중, IRAS Point Source Catalog에는 존재하지 않지만, AKARI FIS Catalog에는 존재하는 원시성들을 뽑아내어 AKARI 원적외선 플럭스의 유무에 따른 Bolometric Luminosity와 Bolometric Temperature의 차이를 비교하였다. 뿐만 아니라 AKARI 원적외선 플럭스의 유무에 따라 연속복사전달 모델로부터 얻어지는 물리량, 특히 성간복사장의 세기가 어떻게 달라지는지 연구하였다.

• Bulletin of the Korean Space Science Society
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• 2009.04a
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• pp.40.2-40.2
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• 2009

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.41.3-41.3
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• 2019

Ices in interstellar environments are well traced mostly by their absorption features in the near- to mid-infrared spectrum. The infrared camera (IRC) aboard AKARI provides us the near-infrared spectroscopic data which cover $2.5-5.0{\mu}m$ with a spectral resolution of R ~ 120. Our AKARI spectroscopic survey of young stellar objects (YSOs), including low-luminosity protostars and background stars, revealed the absorption features of $H_2O$, $CO_2$, CO, and XCN ice components. We present near-infrared spectra of the observed targets and compare their ice abundances with those previously derived from various YSOs and the background stars behind dense molecular clouds and cores. In addition, we suggest possible science cases for SPHEREx, NASA's new near-infrared space observatory, based on the results from our AKARI IRC spectroscopic study.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.63-65
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• 2017

The zodiacal light emission is the thermal emission from the interplanetary dust and the dominant diffuse radiation in the mid- to far-infrared wavelength region. Even in the far-infrared, the contribution of the zodiacal emission is not negligible at the region near the ecliptic plane. The AKARI far-infrared all-sky survey covered 97% of the whole sky in four photometric bands with band central wavelengths of 65, 90, 140, and $160{\mu}m$. AKARI detected the small-scale structure of the zodiacal dust cloud, such as the asteroidal dust bands and the circumsolar ring, in far-infrared wavelength region. Although the most part of the zodiacal light structure in the AKARI far-infrared all-sky image can be well reproduced with the DIRBE zodiacal light model, there are discrepancies in the small-scale structures. In particular, the intensity and the ecliptic latitude of the peak position of the asteroidal dust bands cannot be reproduced precisely with the DIRBE models. The AKARI observational data during more than one year has advantages over the 10-month DIRBE data in modeling the full-sky zodiacal dust cloud. The resulting small-scale zodiacal light structure template has been used to subtract the zodiacal light from the AKARI all-sky maps.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.383-389
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• 2012

This report presents a summary of the Legacy of AKARI: A Panoramic View of the Dusty Universe meeting held between 27-29th February 2012 at Jeju Island, South Korea.

• 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.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.145-146
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• 2012

We present the results from B-, R-, I-, J- and H-band observations of the NEP-Wide survey field. The NEP-Wide survey is an AKARI survey of the North Ecliptic Pole covering ~ 5 square degrees area. Our optical/NIR imaging supports the AKARI IR imaging data by providing a crucial coverage in the optical/NIR. The optical data were obtained in 2007 using the 1.5 m telescope and SNUCAM at Maidanak Observatory, Uzbekistan. The NIR data were obtained in 2008 with FLAMINGOS on the KPNO 2.1 m telescope. We used IRAF, SExtractor, SCAMP, and SWarp for reducing the raw data, I-band fringe pattern removal, astrometry, standard photometry calibration, and source detection. Our optical-NIR data reach the depths of B ~ 23.4, R ~ 23.1, I ~ 22.3, J ~ 21.05, and H ~ 20.64 AB mag at 5-sigma. Here, we present the astrometric accuracy, galaxy number counts, completeness, and reliability, as well as redshift tracks of some normal galaxies and quasars on the B - R vs. R - I color-color diagram. The photometric data are being used for identifying optical counterparts of the IR data provided by AKARI, studying their SEDs, and selecting interesting objects for spectroscopic follow-up studies.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.151-153
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• 2017

Early-type galaxies (ETGs) are generally dominated by old low-mass stars, which are not very productive of dust, and hot interstellar plasmas, which are very destructive of dust. Thus ETGs provide harsh environments for survival of dust. It has been found that some ETGs contain a large amount of dust, and yet its supply mechanism is not understood well. We present the result of a systematic study of dust in ETGs with the AKARI mid- and far-infrared all-sky surveys. From the AKARI result and the Ks band data obtained by ground-based telescopes, we find that there is a global correlation between the dust mass and stellar luminosity. We also compare the AKARI all-sky survey result with the CO data to discuss origins of dust in ETGs.