• Title/Summary/Keyword: high resolution spectra

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HIGH RESOLUTION NEAR-INFRARED SPECTRA OF NEARBY QUASAR, PG1426+015

  • Le, Huynh Anh Nguyen;Pak, Soo-Jong;Im, Myung-Shin;Ho, Luis C.
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.51.1-51.1
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    • 2012
  • We observed low-z quasar PG1426+015 (z=0.086), using the near-IR high resolution echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. Using an Adoptive Optics system, the full width at half maximum of the point spread function was about 0.3 arcsec, which can effectively separate the quasar spectra from the host galaxy spectra. We also maximize the total exposure time up to several hours per target, and develop data reduction methods to increase the signal-to-noise ratios. This poster presents the data reduction processes and sample spectra from the quasar and its host galaxy. These spectral lines will be used to study the physical mechanism of quasars, and the velocity dispersions of the stars in the bugle of the host galaxy.

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Evaluation of Hydration Effect on Human Skin by $^1H$ MRS at 14.1T

  • Choi Chi-Bong;Hong Sung-Tak;Choe Bo-Young;Woo Dong-Chul;Yoon Seong-Ik;Cho Ji-Hyun;Lee Chul-Hyun;Cheong Chae-Joon;Park Sang-Yong;Oh Chil-Hwan
    • Journal of the Korean Magnetic Resonance Society
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    • v.10 no.1
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    • pp.105-114
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    • 2006
  • Purpose: We achieved high resolution MR imaging and spectra of human skin in vitro with using a 14.1 T MRI/MRS system, and evaluated the hydration effect of various cosmetic products by measuring the skin's. moisture concentration. Materials and Methods: We used the Bruker 14.1 T MRI/MRS system with a vertical standard bore that was equipped with a DMX spectrometer gradient system (200 G/cm at a maximum 40 A), RF resonators (2, 5 and 10 mm) and Para Vision software. Spin echo and fast spin echo pulse sequences were employed for obtaining the high resolution MR images. The 3D-localized point resolved spectroscopy (PRESS) method was used to acquire the MR spectra. Results: The high resolution MR images and spectra of human skin in vitro were successfully obtained on a 14.1 T system. The water concentration of human skin after applying a moisturizer was higher than that before applying a moisturizer. Conclusions: The present study demonstrated that the high-resolution MR images and spectra of human skin from a high field NMR instrument could be applicable to evaluating the hydration state of the stratum corneum.

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IGRINS Spectral Library

  • Park, Sunkyung;Lee, Jeong-Eun;Kang, Wonseok;Lee, Sang-Gak;Chun, Moo-Young;Kim, Kang-Min;Jeong, Ueejeong;Yuk, In-Soo;Jaffe, Daniel T.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.71.2-71.2
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    • 2015
  • We present the high-resolution near-infrared spectra of standard stars observed with Immersion Grating Infrared Spectrograph (IGRINS). IGRINS covers the full spectral range of H and K bands simultaneously with a high spectral resolution (R=40,000), revealing many previously undetected and/or unknown lines. In this work, we present preliminary results of spectroscopic diagnostics for stellar physical parameters. Our ultimate goal is to provide a library of near-infrared spectra of standard stars, which covers all spectral types and luminosity classes, with a high-resolution and high signal to noise ratio ($SNR{\geq}200$).

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Impact of Interstellar Na on the Estimation of Na Abundance from Low-resolution Stellar Spectra.

  • Park, Hyejin;Lee, Young Sun
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.68.4-68.4
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    • 2019
  • It is inferred that many stars in the Galactic halo or bulge were once members of globular clusters (GCs), which are now dissolved. To distinguish the GC-originated stars, which can provide valuable information on the origin of the bulge and halo, from the in situ field stars, the Na abundance plays an important role. However, the interstellar Na in certain directions can unnecessarily enhance the estimate of the Na abundance from stellar spectra due to blended Na D lines unless the spectral resolution is very high, which allows to resolve the lines from the interstellar Na. In this study, we present a means of correcting the Na abundance affected by the interstellar Na in the low-resolution of the Sloan Digital Sky Survey stellar spectra.

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Variable Temperature High-Resolution 19F MAS Solid-State NMR Characterization of Fluorocarbon Rubbers

  • Park, Tae-Joon;Choi, Sung-Sub;Kim, Ji-Sun;Kim, Yong-Ae
    • Bulletin of the Korean Chemical Society
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    • v.32 no.7
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    • pp.2345-2350
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    • 2011
  • Variable temperature high-resolution $^{19}F$ magic angle spinning (MAS) solid-state NMR spectroscopy was used to characterize fluorocarbon (FKM) rubbers. The high-resolution spectra of copolymers made from two monomers, vinylidene fluoride and hexafluoropropene, and terpolymers composed of vinylidene fluoride, hexafluoropropene, and tetrafluoroethylene, were obtained using MAS speeds of up to 18 kHz combined with high temperatures of up to 200 $^{\circ}C$ at a magnetic field strength of 9.4 Tesla. From these high resolution solid-state NMR spectra, we were able to assign the spectral peaks and differentiate the copolymer FKM from the terpolymer FKM. We also determined quantitatively the monomer compositions of each FKM rubber.

Calibration of Stellar Isochrones for G- and K-type Dwarfs based on High-Resolution Spectra

  • Lim, Yeseul;An, Deokkeun
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.56.3-57
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    • 2016
  • We present a recent progress on calibration of stellar isochrones based on a set of high-resolution spectra for 170 G- and K-type dwarfs in the solar neighborhood. We compare observed magnitudes of these stars in a number of broad passbands [UB(B_T)V(V_T)RIJHK] with model magnitudes generated using ATLAS9 synthetic library at the previously derived set of spectroscopic parameters. We find systematic offsets in colors from these passbands, which are mainly revealed as a function of effective temperature of stars. In order to remove these systematic color mismatches, we derive correction functions and apply them to the model spectra.

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Near-Infrared Spectra of Super Star Clusters in M82

  • Nguyen, Kim Ngan N.;Pak, Soo-Jong;Im, Myung-Shin;Ho, Luis C.
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.61.2-61.2
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    • 2012
  • We observed selected super cluster regions in M82 with 5'5 arcsec field-of-view using near-IR high resolution echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. The slit width of 0.15 arcsec makes the high resolution (R ${\approx}$ 20,000) spectra in the H and K bands. In this poster, we present sample spectra of [FeII] lines and ro-vibration lines of $H_2$ which trace ionic shocks in the intercloud regions and molecular shocks. The line widths of $Br{\gamma}$ line are also measured to derive the velocity dispersion within the super star clusters.

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SIMULTANEOUS OBSERVATIONS OF HIGH RESOLUTION SPECTRA OVER A SUNSPOT UMBRA

  • Yun, Hong-Sik;Beebe, Herbert A.;Baggett, Wayne
    • Journal of The Korean Astronomical Society
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    • v.13 no.1
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    • pp.1-8
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    • 1980
  • Simultaneous observations of high resolution spectra of CaII H, K, ${\lambda}8542\;and\;{\lambda}8498$ have been made over a sunspot umbra (SPO 5007) by means of Sacramento Peak Observatory's HIRKHAD program with the Echelle spectrograph at the Vacuum Tower Telescope. The observed spectra scanned by SPO's fast microphotometer have been reduced for later theoretical interpretations. The reduced profiles, sampled over a region which is thought to be coolest over the spot, are presented in units of absolute intensity. The core intensity ratios of $I(K_3)/I(H_3);and\;I({\lambda}8498)/I({\lambda}8542)$ arc found to be 1.3 and 1.14, respectively.

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SEARCH FOR AN OI EMISSION AT $1304{\AA}$ IN JOVIAN AUROAL SPECTRA

  • Kim, Sang-J.;Kim, Yong-H.
    • Publications of The Korean Astronomical Society
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    • v.10 no.1
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    • pp.127-134
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    • 1995
  • Recent discovery of an Io-related feature in Jupiter's auroral regions prompted us to search for an or multiplet at $1304{\AA}$ in IUE aurora spectra. In three independent IUE spectra taken on January 18, 1981, we found an emission structure at $1304{\AA}$, with a signal-to-noise of about three. If the structure is due to the OI emission, then it is a direct evidence of oxygen ion precipitation, which may originate from Io and Io torus. The emission rates of the $H_2$ band systems and the or multiplet are about 50 kR and 150 R, respectively. We have constructed high resolution model spectra with the estimated emission rates of $H_2$, OI and SI for the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope. The model spectra clearly show the or and SI mulitplets separated from crowded $H_2$ Lyman and Werner band lines, and therefore it is promising to detect the OI and SI multiplets with the GHRS. Given the possibility that the lo-related feature may be caused by ion precipitations from the Io flux tube, it is likely that the OI emission may be detected in the footprint area of the IO flux tube.

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High resolution spectroscopic study of the peculiar globular cluster M22 (NGC 6656)

  • Kim, Hyeong-Jun;Lee, Jae-Woo
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.65.1-65.1
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    • 2017
  • We present the high-resolution spectroscopic study of the red-giant branch (RGB) stars in the peculiar globular cluster M22 (NGC 6656). We obtained high-resolution spectra of 55 RGB stars using the CTIO 4-m telescope and the HYDRA multi-object spectrograph. By employing an improved LTE analysis method, we measured accurate elemental abundances. In this talk, we will discuss the differences in the chemical composition between the two stellar populations in the context of the formation of M22.

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