• 천문학회보
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• 제44권2호
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• pp.48.1-48.1
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• 2019

We found a diffuse Hα feature with a large size of ~2' around a Herbig star, MWC 1080. It shows a strong correlation with the elongated outflow cavity centered on the star. To investigate the diffuse Hα source and the molecular cavity in detail, we carried out the high-resolution NIR spectroscopy using IGRINS. We detected six hydrogen Brackett line series, seven H2 lines, and an [Fe II] forbidden line. With the obtained spatial, kinematic, and line ratio results, we discuss the characteristics of the central MWC 1080A, the NE outflow cavity, and the SE molecular cloud regions separately. Most of the bright Brγ sources around MWC 1080A were found to be reflection nebulae, but a point-like Brγ source close to another young star, MWC 1080E, was identified as a distinct source due to MWC 1080E itself. The narrow components of the H2 lines observed around MWC 1080A were found to trace PDRs located on the wall of the main outflow cavity. Based on the shock-excited H2 and [Fe II] lines detected just inside a bow-shock shape Hα feature, we suggest that it represents the actual shock at the head of the NE outflow from MWC 1080A. Also, we newly detected the shock-excited H2 and [Fe II] lines with highly blueshifted velocities in the SE molecular cloud region. They could be related to unrevealed outflows from other young stars existing around MWC 1080A.

• 천문학회보
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• 제34권1호
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• pp.60.2-60.2
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• 2009

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권1호
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• pp.33.5-34
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• 2009

• 천문학회보
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• 제39권2호
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• pp.91.1-91.1
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• 2014

IGRINS (the Immersion GRating INfrared Spectrometer) is a high resolution wide-band infrared spectrograph developed by the Korea Astronomy and Space Science Institute (KASI) and the University of Texas at Austin (UT). This spectrograph has H-band and K-band science cameras, both of which use Teledyne's $2.5{\mu}m$ cutoff $2k{\times}2k$ HgCdTe HAWAII-2RG CMOS science grade detectors. Teledyne's cryogenic SIDECAR ASIC boards and JADE2 USB interface cards were installed to control these detectors. We performed lab experiments and test observations to optimize and evaluate the detector systems of science cameras. In this presentation, we describe a process to optimize bias voltages and way to reduce pattern noise with reference pixel subtraction schemes. We also present measurements of the following properties under optimized settings of bias voltages at cryogenic temperature (70K): read noise, Fowler noise, dark current, and reference-level stability, full well depth, linearity and conversion gain.

• 천문학회보
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• 제42권1호
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• pp.54.1-54.1
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• 2017

The UKIRT Wide-field Infrared survey for Fe+(UWIFE) is an unbiased survey of the first Galactic quadrant, with narrow-band filter centered on $1.644{\mu}m$. This survey covers $7^{\circ}$ < l < $62^{\circ}$ and |b| < $1.5^{\circ}$, where active interaction of stars and interstellar medium is expected. With median seeing of 0.8 arcsec, 5 - sigma detection limit of 18.7 mag and surface brightness limit of $8.1{\times}10^{-20}W\;m^{-2}arcsec^{-2}$, this survey gives an opportunity to statistically study Galactic [Fe II] - emitting sources for the first time. In order to identify Ionized Fe Objects (IFOs) in survey area systematically, we conducted visual inspection and automatic detection simultaneously. Total of ~300 extended IFOs are identified, most of them are found out to be part of supernova remnants (SNRs), young stellar objects, HII regions and planetary nebulae. The majority of IFOs are new discoveries which reveal shocked structures in high-extinction region. Spatial distribution of IFOs suggest that they trace Galactic structure. As a part of spectroscopic follow-up, we observed SNR candidate IFO J183740.829-061452.41 with IGRINS (Immersion Grating Infrared Spectrograph, Yuk+2010), mounted on 2.7m Harlan Smith telescope. This unknown arc-like, 6'-long IFO is coincident with inner part of radio continuum loop G25.8+0.2, which has been known as HII region. However, interior of this radio shell is filled with diffuse soft X-ray emission, and possible association of hard X-ray pulsar / pulsar wind nebula makes the nature of the IFO unclear. The H and K-band 2D spectrum shows shock-ionized [Fe II] filaments, which is apart from photoionized HII filaments. In this presentation we present basic statistics of newly identified IFOs, as well as the follow-up study of IFO J183740.829-061452.41.

• 천문학회보
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• 제39권2호
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• pp.90-90
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is the first astronomical spectrograph that uses a silicon immersion grating as its dispersive element. IGRINS fully covers the H and K band atmospheric transmission windows in a single exposure. It is a compact high-resolution cross-dispersion spectrometer whose resolving power R is 40,000. An individual volume phase holographic grating serves as a secondary dispersing element for each of the H and K spectrograph arms. On the 2.7m Harlan J. Smith telescope at the McDonald Observatory, the slit size is $1^{{\prime}{\prime}}{\times}15^{{\prime}{\prime}}$. IGRINS has a plate scale of 0.27" pixel-1 on a $2048{\times}2048$ pixel Teledyne Scientific & Imaging HAWAII-2RG detector with a SIDECAR ASIC cryogenic controller. The instrument includes four subsystems; a calibration unit, an input relay optics module, a slit-viewing camera, and nearly identical H and K spectrograph modules. The use of a silicon immersion grating and a compact white pupil design allows the spectrograph collimated beam size to be 25mm, which permits the entire cryogenic system to be contained in a moderately sized ($0.96m{\times}0.6m{\times}0.38m$) rectangular Dewar. The fabrication and assembly of the optical and mechanical components were completed in 2013. From January to July of this year, we completed the system optical alignment and carried out commissioning observations on three runs to improve the efficiency of the instrument software and hardware. We describe the major design characteristics of the instrument including the system requirements and the technical strategy to meet them. We also present the instrumental performance test results derived from the commissioning runs at the McDonald Observatory.

• 천문학회보
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• 제34권2호
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• pp.63.2-63.2
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• 2009

• 천문학회보
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• 제36권2호
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• pp.153.1-153.1
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• 2011

For the stars cooler than the Sun, it is difficult to determine the stellar parameters and chemical abundances because of the strong molecular lines in the optical region. Therefore the NIR high-resolution spectra, such as those obtained by IGRINS would be a solution to determine the stellar parameters for late-type stars, such as M dwarfs. As using the NIR high-resolution spectra, we are expecting that it would be more reliable to compare observed spectra with synthetic spectra for the stellar parameters. In order to confirm the method by using high-resolution spectra in NIR band, it should be cross-checked against the stellar parameters from optical high-resolution spectra. We have derived the stellar parameters of M dwarfs using the synthetic spectra in the long wavelength region of the optical spectra (over 8000 $\bar{A}$), which is relatively less contaminated by molecular lines as well as telluric lines.

• 천문학회보
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• 제41권1호
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• pp.59.2-59.2
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• 2016

보현산천문대가 준공되면서, 1.8 m 망원경이 연구자들에게 공개된지 20년이 되었다. 당시 보현산 천문대의 연구자들은 1.8 m 망원경을 도약망원경이라 부르면서, 우리나라 천문학의 비약적인 발전의 토대가 되기를 희망하였다. 보현산천문대 10주년 기념 담양 워크샵에서 BOES의 성과를 발표한 이후 10년 동안, 천문연구원 광학천문기술 그룹에서는 BOES 편광분광기와 IGRINS를 개발 완료하였으며, GMTNIRS의 개념설계와 GCLEF의 기본설계가 진행되었다. 여기에서는 그동안 개발된 고분산 천체분광기 프로젝트의 성과를 정리하고, 앞으로의 계획을 논의한다.

• 천문학회보
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• 제41권1호
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• pp.58.1-58.1
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• 2016

K-GMT Science Program, operated by Center for Large Telescopes (CfLAT) in Korea Astronomy and Space Science Institute (KASI), aims to promote the scientific researches by providing the access to the observational facilities such as 4-8m class telescopes and specialized instruments. In 2016, we plan to make various instruments with MMT and Gemini Observatory as well as IGRINS with 2.7m HJS Telescope in McDonald Observatory available to Korean Astronomical Community. We will present the current status and future prospect as well as some early results made from the K-GMT Science Program in past years.