• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.85.1-85.1
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• 2014

K-GMT Science Group (KGSG) is actively promoting community-wide science operations for the GMT era in 2020's. These include K-GMT Science Program, K-GMT Science White Paper Initiative, K-GMT Summer School, and science operation of IGRINS. We will introduce the current status and the plan for 2014 of the various KGSG activities and invite the participation of the community members.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.223.2-223.2
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• 2012

Grating spectrograph observation in near-infrared bands requires wavelength calibrations. We first need to extract order-strips from the echellogram data using flat images, and then to correct the spatial distortions and wavelength scales of the order strips using calibration arc lamps or the telluric OH emission lines. For very high resolution spectrograph using echelle, however, the arc lamps do not have enough emission lines in the order-strips, so we usually use the OH lines for accurate wavelength calibrations in wavelengths shorter than 2.3 microns. In this poster, we present wavelength calibration methods for longer wavelength bands using the telluric absorption lines in early-type stellar spectra and the telluric atmospheric transmission models. This technique will be applied to the data reduction pipeline for the IGRINS.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.29.4-30
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• 2018

Welcome to Gemini! In this overview, I'll describe the governance, operations, and capabilities of the Gemini telescopes. I'll also describe Gemini's vision and plans for the future. Gemini is very adaptable and has multiple ways to apply for time, multiple ways to collect your data, and multiple instrument capabilities ready for your observations. Gemini also runs a wide-reaching program to develop and improve our instrumentation capabilities. We run an upgrade program for our existing instruments that includes an annual public call for proposals, a visitor instrument program that brings instruments like IGRINS to our telescopes for short to semi-permanent runs, and a facility program that provides entirely new instruments like GHOST and SCORPIO to Gemini for full public use. Through these programs, you can interact with Gemini in a number of ways to support your scientific needs in the most efficient way possible.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.80.2-80.2
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• 2021

Galactic young massive clusters are the ideal laboratories to study massive stellar evolution. Unfortunately, such objects are rare. Of particular interest are so-called Red Supergiant Clusters (RSGCs) that are currently only found toward the Scutum-Crux Galactic arm. Confirming their nature as RSGC is often not straight-fortward as distinguishing RSGs from AGB stars is still difficult even with high spectral resolution spectra. Here we report that broad band colors using 2MASS JHK and GAIA G band data can be useful in reducing the AGB contamination, thus providing selection criteria that effectively reveal the known RSGCs with negligible false positives. On the other hand, we suggest that RSGC4, one of the proposed RSGC candidates, may not be a cluster of RSGs as their colors are not compatible with our selection criteria. We discuss the nature of these stars together with our IGRINS spectroscopic observations. We also employ the same selection criteria to search for RSGC candidates in other parts of the plane, resulting in no prominent candidates.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.54.2-54.2
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• 2017

We present the results of high-resolution optical (R ~ 30,000) and near-infrared (R ~ 45,000) spectroscopic monitoring observations of a new FU Orionis-like young stellar object, 2MASS J06593158-0405277. FU Orionis objects (FUors) are well-studied examples of episodic accretion because of their outburst phenomenon. Recently, 2MASS J06593158-0405277 exhibited an outburst and was identified as an FUor. It provides an important opportunity to investigate the whole FUors phenomenon from its pre-outburst to its post-outburst phase. We observed 2MASS J06593158-0405277 with the Bohyunsan Optical Echelle Spectrograph (BOES) of the Bohyunsan Optical Astronomy Observatory (BOAO) and the Immersion GRating INfrared Spectrograph (IGRINS) of Harlan J. Smith Telescope (HJST) at the McDonald observatory since December 24, 2014. We detected a number of lines and present here our analysis for time variations of those spectral lines.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.38.2-38.2
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• 2017

We present the observational study toward the multiple outflows around $LkH{\alpha}$ 234 star formation region. The high-resolution, near-IR spectral mapping using the Immersion Grating Infrared Spectrograph (IGRINS) allowed us to distinguish at least four separate outflows with the molecular hydrogen ($H_2$) and forbidden iron ([Fe II]) emission lines. The outflow associated with the radio continuum source VLA 3B is detected in both H2 and [Fe II] emission, while the outflows driven by MM 1, VLA 2 sources were only detected in $H_2$, indicating the different physical conditions of outflows. We confirm the axis of VLA 3B jet, the position angle of ${\sim}240^{\circ}$. We firstly identified the redshifted, near-IR H2 outflow associated with VLA 2, which is coincident with the previous detections of $H_2O$ masers. From the $H_2$ line ratios, we interpret the gas properties of the shock excited blue- and redshifted components, and UV excited surrounding photodissociation region. We also discuss the origin of the high-velocity (|VLSR| > $150km\;s^{-1}$) $H_2$ emission.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.65.3-66
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• 2018

We present the results of high-resolution optical (R ~ 30,000) and near-infrared (R ~ 45,000) spectroscopic monitoring observations of a new FU Orionis-like young stellar object, 2MASS J06593158-0405277. FU Orionis objects (FUors) are well-studied examples of episodic accretion because of their outburst phenomenon. Recently, 2MASS J06593158-0405277 exhibited an outburst and was identified as a FUor. It provides an important opportunity to investigate the whole FUors phenomenon from its pre-outburst to its post-outburst phase. We monitored 2MASS J06593158-0405277 with the BOES and the IGRINS since Dec 25, 2014 (UT). We detected several wind and disk features and present here our analysis for time variations of those spectral lines.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.66.4-66.4
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• 2019

NGC 6822 is a dwarf irregular galaxy whose metal abundance is lower than of the Large Magellanic Cloud. Hubble V is the brightest HII complex where molecular clouds surround the core cluster of OB stars. Because of its proximity (d = 500 kpc), we can resolve the star-forming regions on parsec scales (1 arcsec = 2.4 pc). Using the high-resolution (R = 45,000) near-infrared spectrograph, IGRINS, we observed molecular hydrogen emission lines from photo-dissociation regions (PDRs) and $Br{\gamma}$ emission line from ionized regions. In this presentation, we compare our data PDR models in order to derive the density distribution of the molecular clouds on parsec scales and to estimate the total mass of the clouds.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.43.5-44
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• 2018

한국천문연구원은 미국 텍사스대학교(UT)와 협력하여 2009년부터 2013년까지 IGRINS 분광기를 개발하였다. IGRINS는 UT의 맥도널드(McDonald) 천문대 2.7미터 망원경과 로웰(Lowell) 천문대의 4.3미터 망원경, 제미니(Gemini) 천문대 8.1미터 망원경에 장착하여 성공적으로 사용되어 왔으며, 최근 한국천문연구원이 제미니 천문대 운영에 정식으로 참여하면서 IGRINS와 유사한 관측기기를 8.1미터 망원경 전용으로 개발해 달라는 요청을 받고 개발계획을 준비하고 있다. 담금격자(immsersion grating)를 사용하는 IGRINS는 거대마젤란망원경(GMT)의 1세대 관측기기 중 하나로 선정된 적외선 고분산 분광기 GMTNIRS의 핵심 요소기술을 검증하기 위한 선행개발 기기의 의미도 갖고 있다. 한국천문연구원은 2011년 UT와 공동으로 GMTNIRS의 개념설계를 수행하였으며, 이후 개발팀에 카네기(Carnegie) 천문대가 합류하여 6.5미터 마젤란(Magellan) 망원경용으로 GMTNIRS와 유사한 담금격자 적외선 분광기를 개발하고 시험운영함으로써 GMTNIRS의 개발을 앞당기는 계획을 추진 중이다.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.43.3-43.3
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• 2017

NGC 6822 is a dwarf irregular galaxy in the Local Group and it is located in 500 kpc, further than the Large Magellanic Cloud and the Small Magellanic Cloud. Therefore, we can study star-forming processes by local condition in NGC 6822 instead of tidal force of the Galactic gravitational field. Hubble V is the brightest of several H II complexes in this galaxy. We observed Hubble V by using IGRINS attached on the 2.7 m telescope at the McDonald Observatory in Texas, US in May 2016. We performed a spectral mapping of $15^{{\prime}{\prime}}{\times} 7^{{\prime}{\prime}}$area on H and K bands, and detected emission lines of bright $Br{\gamma}\;{\lambda}2.1661{\mu}m$ and weak He I ${\lambda}2.0587{\mu}m$. Molecular hydrogen lines of 1-0S(1) ${\lambda}2.1218{\mu}m$, 2-1 S(1) ${\lambda}2.2477{\mu}m$, and 1-0 S(0) ${\lambda}2.2227{\mu}m$ was also detected. These emission lines show the structure of an ionized core and excited surface of clouds by far-ultraviolet photons, photodissociation region (PDR). We present three-dimensional maps of emission line distributions through multi slit scanning data and compare these results with the previous study. This presentation shows the physical structure of the star-forming regions and we discuss a PDR model and an evolution of Hubble V complex.