• 대한원격탐사학회지
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• 제38권6_1호
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• pp.1423-1444
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• 2022

본 연구에서는 대기 및 지표면 인자들에 대한 중적외 파장역의 복사휘도의 민감도를 복사전달모델인 MODerate resolution atmospheric TRANsmission (MODTRAN)6을 이용하여 분석하고 이를 이용하여 야간에 중적외 파장역 만을 이용한 지표면온도 산출 가능성을 평가하였다. 이를 기반으로 야간에 대해 다양한 조건을 반영한 지표면온도 산출식을 개발하고 처방 온도 자료와 현장 관측 자료를 이용하여 개발된 지표면온도 산출식의 수준을 평가하였다. 중적외 파장역을 활용한 위성 원격탐사에 주로 영향을 미치는 대기연직구조, 이산화탄소와 오존, 지표면온도의 일 변동, 지표면 방출률 그리고 위성의 관측각에 대해 민감도 실험을 실시하였다. 이때 분리대기창 기법 활용 가능성을 평가하기 위해 중적외 파장역을 투과율을 근거로 2개의 밴드로 분리한 후 민감도를 분석한 결과 밴드와 관계없이 대기연직구조에 가장 큰 영향을 받으며 지표면 방출률, 지표면온도의 일 변동, 위성의 관측각 순으로 영향을 받았다. 주요 변인 실험 모두에서 대기의 창에 해당되는 밴드 1은 민감도가 낮은 반면 오존과 수증기 흡수가 포함된 밴드 2에서는 민감도가 높아서 분리대기창 기법을 활용하여 지표면온도 산출이 가능할 것으로 판단하였다. 중적외 2개 밴드와 다양한 변인들을 이용하여 개발된 지표면온도 산출식은 복사모의 시 입력된 기준 지표면온도와 상관계수, 편의 그리고 root mean squared error (RMSE)가 각각 0.999, 0.023K과 0.437K의 수준을 보였다. 또한 26개의 현장관측 지표면온도 자료로 검증한 결과 상관계수는 0.993, 편의는 1.875K, RMSE는 2.079K을 보였다. 본 연구의 결과는 대기 및 지표면 조건이 야간의 중적외 두 밴드에 미치는 영향이 다른 특성을 이용하여 지표면온도를 산출할 수 있음을 제시한다. 따라서 향후에는 중적외 파장역 센서를 탑재한 위성자료를 이용하여 지표면온도를 산출하고 그 수준을 평가해 볼 필요가 있다.

• 천문학회보
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• 제37권1호
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• pp.64.2-64.2
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• 2012

The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) project is a next-generation infrared space telescope optimized for mid- and far-infrared observation with a cryogenically cooled 3m-class telescope. It will achieve the high resolution as well as the unprecedented sensitivity from mid to far-infrared range. The FPC (Focal Plane Camera) is a Korean-led near-infrared instrument as an international collaboration. The FPC-S and FPC-G are responsible for the scientific observation in the near-infrared and the fine guiding, respectively. The FPC-G will significantly reduce the alignement and random pointing error through the observation of guiding stars in the focal plane. We analyzed the pointing requirement from the focal plane instruments. The feasibility study was performed to achieve the requirements. Here, we present the role of SPICA/FPC as a fine guiding camera.

• Spatial Information Research
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• 제19권5호
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• pp.37-46
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• 2011

봄 가뭄탐지를 위한 위성영상 활용을 위해 중 저해상 위성영상인 Landsat TM(Thematic Mapper) 영상을 이용하여 기존의 봄철 가뭄 해석에 많이 사용되어온 정규식생지수(NDVI: Normalized Difference Vegetation Index)이외에 MSI(Moisture Stress Index), MidIR Index, II (Infrared Index) 지수들의 가뭄분석 활용가능성을 알아보고자 하였다. 이를 위해 경상북도 영천시를 대상으로 무강수일수에 따른 영상을 선정하여 DN(Digital Number)값의 특성 및 상관성을 분석하고 이와 더불어 가뭄지수와의 비교 분석을 실시하였다. 그 결과 NDVI와 MSI 및 II 지수는 높은 상관관계를 보였으나, MidIR은 낮은 상관관계를 보였으며, 가뭄지수와의 분석에서도 MSI 및 II 지수는 강한 상관관계를 보여주었다. 따라서 MSI와 II 지수를 이용한 가뭄연구를 통해 정보의 다양성 및 정확도를 높일 수 있을 것으로 판단된다.

• 천문학논총
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• 제32권1호
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• pp.83-85
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• 2017

We conducted an unbiased near- to mid-infrared imaging and spectroscopic survey of the Large Magellanic Cloud (LMC) as a part of the AKARI Mission Program "Large-area Survey of the LMC" (LSLMC, PI: T. Onaka). An area of about 10 square degrees of the LMC was observed by five photometric bands (3.2, 7, 11, 15, and $24{\mu}m$) and a low-resolution slitless prism ($2-5{\mu}m$, R ~20) equipped with AKARI /IRC. We constructed and publicly released photometric and spectroscopic catalogues of point sources in the LMC based on the survey data. The catalogues provide a large number of near-infrared spectral data, coupled with complementary broadband photometric data. Combined use of the present AKARI LSLMC catalogues with other infrared point source catalogues of the LMC possesses scientific potential that can be applied to various astronomical studies.

• 천문학회보
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• 제44권1호
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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.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1012-1012
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• 2001

The elegant early experiments of Herschel demonstrated that there is light after the visible spectrum in a region we call the near infrared (NIR). This was followed by the work which showed that the spectrum went further into what we call the mid infrared (MIR). The MIR has been used for many years as a qualitative and quantitative region to measure constituent values. The MIR region contains the fundamental vibrations which can be theoretically calculated from symmetry rules and harmonic oscillator equations. The NIR is not as straight forward because the region from 400-2500 nm does not contain any of the fundamental vibrations only combination bands and overtones. Over the past fifty years efforts to understand the NIR have largely been ignored while the quantitative aspects of the region have been utilized. This presentation will focus on the efforts to define terms for NIR, examine the calculation of combination bands and overtones and ways to interpret the spectra. The interpretation of the NIR has been aided greatly in recent years by the use of two dimensional spectroscopy which allows the correlation of bands in one spectral region with that of the NIR.

• 천문학회보
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• 제42권2호
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• pp.81.2-81.2
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• 2017

Polarized mid-infrared emission from polycyclic aromatic hydrocarbons (PAHs) can provide a crucial test of basic physics of alignment of nanoparticles and opens a potential new window into studying magnetic fields. In this talk, I will present a new model of polarized PAH emission that takes into account the effect of PAH alignment with the magnetic field due to resonance paramagnetic relaxation. I will then present our predictions for the polarization level of the strong PAH emission features from the interstellar medium. I will present the first detection of polarization of PAH emission at 11.3micron which is consistent with our theoretical prediction. Finally, I will discuss important implications of this work for tracing magnetic fields via mid-IR PAH features and for constraining the polarization of anomalous microwave emission that is useful for the quest of CMB B-modes.

• Journal of the Optical Society of Korea
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• 제17권2호
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• pp.142-147
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• 2013

In order to deduce the difficulty of fixing the Ritchey-Chretien (R-C) dual reflective optical system and enhance the stability of the secondary mirror, a compact integral structure is presented here composed of two transmitting and two reflective aspheric surfaces. The four surfaces were manufactured from a single germanium lens and integrated together. The two reflective surfaces formed by coating the inner reflecting films were assembled in one lens. It makes the installation of the two mirrors easier and the structure of the secondary mirror more stable. A design of mid-wave infrared (MWIR) compact imaging system is presented with a spectral range chosen as $3.7-4.8{\mu}m$. The effective focal length is f=90 mm. The field of view (FOV) for the lens is $4.88^{\circ}$. It has good imaging capability with Modulation Transfer Function (MTF) of all field of view more than 0.55 close to the diffraction limitation. Outdoor experiments were carried out and it is shown that the integral catadioptric optical system performs well on imaging.

• 천문학논총
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• 제27권4호
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• pp.217-218
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• 2012

Among the AKARI all-sky survey data, the $9{\mu}m$ diffuse map is crucial to study the polycyclic aromatic hydrocarbon (PAH) emission features on large spatial scales, while the $18{\mu}m$ map is useful to trace hot dust emission. To utilize these advantages, we have improved the AKARI mid-infrared (MIR) all-sky survey diffuse maps. For example, we have established special methods to remove the effects of the ionizing radiation in the South Atlantic Anomaly (SAA) and of the scattered light from the moon. Using improved diffuse map data, we study the properties of PAHs and dust in the Galactic center region associated with high-energy phenomena.

• 천문학논총
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• 제32권1호
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• pp.263-265
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• 2017

We present the mid-infrared (MIR) luminosity function (LF) of local (z < 0.3) star-forming (SF) galaxies in the North Ecliptic Pole (NEP) field. This work is based on the NEP-Wide point source catalogue and the spectroscopic redshift (z) data for ~ 1700 galaxies obtained by the optical follow-up survey with MMT/Hectospec and WIYN/Hydra. The AKARI's continuous $2-24{\mu}m$ coverage and the spectroscopic redshifts enable us to determine the spectral energy distribution (SED) in the mid-infrared and derive the luminosity functions of galaxies. Our $8{\mu}m$ LF finds good agreements with the results from SWIRE field over the wide luminosity range, while showing significant difference from the NOAO deep data in the faint end. The comparison with higher-z sample shows significant luminosity evolution from z > 0.3 to local universe. $12{\mu}m$ LF also shows a clear indication of luminosity evolution.