• Title, Summary, Keyword: Mid infrared spectroscopy

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A $LN_2$-cooled, Broadband cw CO Laser (액체질소 냉각형광대역 cw CO 레이저)

  • Kim, Y.P.;Choi, J.W.;Won, J.W.
    • Proceedings of the KIEE Conference
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    • pp.667-671
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    • 1989
  • The CO laser is one of powerful light source for laser magnetic resonance spectroscopy in the mid-infrared region of the spectrum because of its wideband operational characteristics. In this work, a liquid nitrogen cooled cw CO laser is developed to allow broad-band operation from 5 to 8 ${\mu}m$. The design details will be presented.

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Near-infrared studies of iron knots in Cassiopeia A supernova remnant: I. Spectral classification using principal component analysis

  • Lee, Yong-Hyun;Koo, Bon-Chul;Moon, Dae-Sik;Burton, Michael G.
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.49.1-49.1
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    • 2013
  • We have been carrying out near-infrared (NIR) spectroscopy as well as [Fe II] narrow band imaging observations of Cassiopeia A supernova remnant (SNR). In this presentation, we describe the spectral classification of the iron knots around the SNR. From eight long-slit spectroscopic observations for the iron-bright shell, we identified a total of 61 iron knots making use of a clump-finding algorithm, and performed principal component analysis in an attempt to spectrally classify the iron knots. Three major components have emerged from the analysis; (1) Iron-rich, (2) Helium-rich, and (3) Sulfur-rich groups. The Helium-rich knots have low radial velocities (${\mid}v_r{\mid}$ < 100 km/s) and radiate strong He I and [Fe II] lines, that match well with Quasi-Stationary Flocculi (QSFs) of circumstellar medium, while the Sulfur-rich knots show strong lines of oxygen burning materials with large radial velocity up to +2000 km/s, which imply that they are supernova ejecta (i.e. Fast-Moving Knots). The Iron-rich knots have intermediate characteristics; large velocity with QSF-like spectra. We suggest that the Iron-rich knots are missing "pure" iron materials ejected from the inner most region of the progenitor and now encountering the reverse shock.

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SPICA Near-Infrared Instrument, FPC and its Science

  • Jeong, Woong-Seob;Matsumoto, Toshio;Lee, Dae-Hee;Ree, Chang-Hee;Park, Young-Sik;Moon, Bong-Kon;Park, Sung-Joon;Pyo, Jeong-Hyun;Han, Won-Yong;Lee, Hyung-Mok;Im, Myung-Shin;Koo, Bon-Chul;Ishiguro, Masateru;Woo, Jong-Hak
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.1
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    • pp.76-76
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    • 2011
  • The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) project is a next-generation astronomical mission optimized for mid- and far-infrared observation with a cryogenically cooled 3m-class telescope. Due to its high angular resolution and unprecedented sensitivity, SPICA will enable us to resolve many key issues from the star-formation history of the universe to the planetary formation. As an international collaboration, KASI proposed the near-infrared instrument which is composed of two parts; (1) science observation with the capability of imaging and spectroscopy covering $0.7{\mu}m$ to $5{\mu}m$ (FPC-S) (2) fine guiding to stabilize and improve the attitude (FPC-G). Here, we present the current status of SPICA/FPC.

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Photoemission and Excitation Spectroscopy of cis-Difluoro(1,4,8,11-Tetraazacyclotetradecane) Chromium (III) Perchlorate

  • Park, Jong-Ha;Hong, Yong-Pyo;Park, Yu-Chul;Ryoo, Keon-Sang
    • Journal of Photoscience
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    • v.7 no.1
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    • pp.21-26
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    • 2000
  • The photoemission and excitation spectra of cis-[Cr(cyclam)F$_2$]ClO$_4$ (cyclam = 1,4,8,11-tetraazacy-clotetradecane) taken at 77 K are reported. The 298 K mid- and far-infrared spectra are also measured. The vibrational intervals of the electronic ground state are extracted from the far-infrared and emission spectra. The ten electronic bands due to spin-allowed and spin-forbidden transitions are assigned. The zero-phonon line In the excitation spectrum splits into two components by 169 cm$^{1}$, and the large $^2$E$_{g}$ splitting can be reproduced by the ligand field theory. According to the ligand field analysis, we can confirm that nitrogen atoms of the cyclam ligand have a strong c-donor character, and fluoride ligand also has strong $\sigma$- and $\pi$-donor properties toward chromium(III) ion.n.

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Application of mid-infrared TDLAS to various small molecule diagnostics

  • Lee, Young-Sik
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.25-25
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    • 2010
  • The spectroscopy over a region from 3 to 17 ${\mu}m$ based on the tuneable diode lasers (TDLAS) is the most powerful technique for in situ studies of the diagnostics of small molecules. The increasing interest in small molecules especially containing carbon, oxygen, hydrogen, and fluorine containing ones can be fulfilled by TDLAS at 0.0001 cm-1 resolution, because most of these compounds are infrared active. TDLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species, which can be employed for the time dependent studies in sub micro second scale. Information about gas temperature and population densities can also be derived from TDLAS measurements. Collisional energy transfer between the small molecules can be studied with TDLAS. Also, a variety of free radicals and molecular ions have been detected by TDLAS. Since plasmas with molecular feed gases are used in many applications, there are new applications in industrial field. Recently, the development of quantum cascade lasers (QCLs) offers an attractive new option for TDLAS.

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OPTICAL SPECTROSCOPY AND LIGAND FIELD PARAMETERS OF CIS-DIBROMO(1,4,8,11-TETRAAZACYCLOTETRADECANE) CHROMIUM(III) BROMIDE

  • Choi, Jong-Ha
    • Journal of Photoscience
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    • v.4 no.3
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    • pp.121-125
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    • 1997
  • The 77 K emission and excitation, and room-temperature visible spectra of cis[Cr(cyclam)Br$_2$]Br (cyclam=1,4,8,11-tetraazacyclotetradecane) are reported. The mid- and far-infrared spectra at room-temperature are also measured. The vibrational intervals of the electronic ground state are extracted from the far-infrared and emission spectra. The ten electronic bands due to spin-allowed and spin-forbidden transitions are assigned. It is found that nitrogen atoms of the cyclam ligand have strong $\sigma$-donor characters, but bromide ligand has weak $\sigma$- and $\pi$-donor properties toward chromium(III) ion. The zerophonon line in the excitation spectrum splits into two components by 172 cm$^{2-}$, and the large $^2E_g$ splitting can be reproduced by the ligand field theory.

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Near-infrared Spectroscopy of Young Stellar Objects around the Supernova Remnant G54.1+0.3

  • Kim, Hyun-Jeong;Koo, Bon-Chul;Moon, Dae-Sik;Lee, Sang-Gak
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.68.2-68.2
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    • 2010
  • We present near-infrared (NIR) spectra of 6 young stellar objects (YSOs) around the supernova remnant G54.1+0.3 obtained with TripleSpec, a slit-based NIR cross-dispersion echelle spectrograph on th 5-m Palomar Hale telescope covering the entire NIR atmospheric window of 1-2.4 micron. These YSOs, whose formation was possibly triggered by the progenitor of G54.1+0.3, show significant mid-infrared (MIR) excess and have been proposed to be late O- and early B-type YSOs based on their spectral energy distribution. Our TripleSpec observations reveal the existence of strong H and He I lines, consistent with the previous interpretation of their spectral types, while the absence of Br-gamma emission line indicates that the YSOs do not have a nearby circumstellar disk. We discuss the relation between these YSOs and G54.1+0.3 based on the TripleSpec data and previous photometric data as well.

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Introduction to AMUSES : AKARI survey with a window of opportunity

  • Kim, Ji-Hoon;Im, Myung-Shin;Lee, Hyung-Mok;Lee, Myung-Gyoon
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.76.1-76.1
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    • 2010
  • With advancement of infrared space telescopes during the past decade, infrared wavelength regime has been a focal point to study various properties of galaxies, such as stellar mass, dust contents and dust-hidden star formation with respect to evolution of galaxies. Polycyclic Aromatic Hydrocarbons (PAHs) have emerged as one of the most important features since these features dominate mid-infrared spectra of galaxies. These PAH features provide a great handle to calibrate star formation rates and diagnose ionized states of grains. However, PAH $3.3{\mu}m$ feature has not been studied as much as other PAH features since it is weaker than others and resides outside of Spitzer's capability. Still its calibration and characterization are important since it will be the only PAH feature accessible by JWST for high-z galaxies. AKARI mJy Unbiased Survey of Extragalactic Sources in 5MUSES (AMUSES) intends to take advantage of AKARI's capability of spectroscopy on 2 to 5 ${\mu}m$ to provide an unbiased library of 44 sample galaxies selected from a parent sample of 5MUSES, one of Spitzer legacy projects. For these 3.3mm flux limited sample galaxies whose redshifts range between 0 < z <1, AMUSES will calibrate PAH $3.3{\mu}m$ as a SFR while measuring ratios between PAH features and investigating Bra's potential as a SFR indicator. We present preliminary results of AMUSES.

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