• 천문학회보
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• 제35권1호
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• pp.55.2-55.2
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• 2010

We present a photometric and spectroscopic study of the globular clusters (GCs) in the giant elliptical galaxy NGC 4636 in the Virgo cluster. The photometry of the GCs is based on HST/WFPC2 images for the inner region and deep, wide field Washington $CT_1$ CCD images for the outer region. We investigated the color distribution, the radial number density profile, the spatial distribution, and the mean color of the bright blue GCs about the GCs in NGC 4636. We obtained spectra of the GC candidates in NGC 4636 using the Multi-Object Spectroscopy (MOS) mode of Faint Object Camera and Spectrograph (FOCAS) on the SUBARU 8.2m Telescope. We measured the velocities for 105 GCs in NGC 4636. Using the 238 GCs obtained from combining our results with data in the literature, we investigated the kinematics of the GC system of NGC 4636: the rotation, the velocity dispersion, the radial variation, and the orbit. We also investigated the distribution and the radial variation of the metallicities, ages, and alpha-elements of the GCs in NGC 4636 derived using the absorption lines. We compared the GC kinematics of NGC 4636 with those of other six gEs, finding that the kinematic properties of the GCs are diverse among gEs. We found several correlations between the kinematics of the GCs and the global parameters of their host galaxies. Finally we discuss the implication of the results for the formation models of the GC system in gEs, and suggest a mixture scenario for the origin of the GCs in gEs.

• 천문학회보
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• 제42권1호
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• pp.42.4-43
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• 2017

We investigate the long-period radial velocity (RV) variations for M giant HD 18438 and K giant HD 158996 using the high-resolution Bohyunsan Observatory Echelle Spectrograph at the 1.8m telescope of Bohyunsan Optical Astronomy Observatory in Korea. These two target stars are important because HD 18438 is the largest star and HD 158996 is the brightest star for exoplantary system candidate so we can understarnd how evolved stars affect planets by researching these stars. We calculated precise RV measurements of 38 and 24 spectra from November 2010 to January 2017 and June 2010 to January 2017, respectively. We dreived the RV variation period for 719.0 days of HD 18438, 775.6 days for HD 158996. We conclude that the RV variation of HD 158996 is caused by planetary companion which has the mass of 14.7 MJup, semi-major axis of 2.2 AU, and eccentricity of 0.27 assuming the stellar mass of $2.34M{\odot}$. On the other hand, the origin of RV variation of HD 18438 with period of 719.0 days is still uncertain. It might be caused by stellar chromospheric activity or planetary companion, so more observations and tests are required.

• 천문학회보
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• 제42권1호
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• pp.51.3-51.3
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• 2017

To investigate the connection between radio activity and AGN outflows, we present a study of ionized gas kinematics by using [O III] ${\lambda}5007$ emission line along the radio jet for six radio AGNs. These AGNs are selected based on the radioactivity (L1.4GHz ${\geq}$ 1039.8 erg s-1) as well as optical properties as type 2 AGNs. By using the high spatial resolution of the Red Channel Cross Dispersed Echellette Spectrograph at the Multiple Mirror Telescope, we investigate in detail the [O III] and stellar kinematics. We spatially resolve and probe the central AGN-photoionization sizes, which is important in understanding the structures and evolutions of galaxies. We find that the typical central AGN-photoionization sizes of our targets are in range of 1.8-3.8 kpc. We study the [O III] kinematics along the radio jets to test whether there is a link between gas outflows in the narrow-line region and radio jet emissions. Contrary to our expectation, we find no evidence that the gas outflows are directly connected to radio jet emission.

• 천문학회보
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• 제42권1호
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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.

• 천문학회보
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• 제43권1호
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• pp.68.4-69
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• 2018

GMACS is one of the instruments for the Giant Magellan Telescope (GMT) which will provide wide field, multi-object, moderate resolution spectroscopy of faint targets. KHU (Kyung Hee University) is in charge of control software of GMACS. As a first step, the Slit Mask Exchange Mechanism Prototype (SMEM-P) will be used as a preliminary example to make development process between electronics and high level software. Recently, we have developed a sample program to communicate with low level devices via EtherCAT. It is expected to be a mockup design for software and control system of GMACS. In this poster, we show the development process and test operation results of control software for SMEM-P.

• 천문학회보
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• 제43권1호
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• pp.43.2-44
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• 2018

One of the keys to interpreting the characteristics and evolution of interstellar medium in the Milky Way is to understand the distribution of hot gas ($10^5-10^6K$). Gases in this phase are difficult to observe because they are in low density and lack of easily observable tracers. Hot gases are observed mainly in the emission of the FUV ($912-1800{\AA}$), EUV ($80-912{\AA}$), and X-rays (T> $10^6K$) of which attenuation is very high. Of these, FUV emission lines originated from high-stage ions such as O VI and C IV can be the most effective tracers of hot gases. To determine the spatial distribution of O VI and C IV emissions, we have analyzed the spectra obtained from FIMS (Far-ultraviolet IMaging Spectrograph), which covers about 80 percent of the sky. The hot gas volume filling factor, which varies widely from 0.1 to 0.9 depending on the supernova explosion frequency and the evolution model, has been calculated from the O VI and C IV maps. The hot gas generation models has been verified from the global distribution of O VI and C IV emissions, and a new complementary model has been proposed in this study.

• 한국지구과학회지
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• 제30권5호
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• pp.611-621
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• 2009

Using the spectroscopic data secured with the Hamilton Echelle Spectrograph at Lick Observatory, we found the physical condition of the planetary Nebula NGC 6210. The spectral line profiles of the permitted and forbidden lines have been analyzed using IRAF and StarLink/Dipso. The hydrogen number densities ($N_H$) are 2,000-20,000 $cm^{-3}$, and the electron temperatures are 8,100-10,300 K based on the forbidden lines. The expansion velocities, derived from the Full Width at Half Maximum (FWHM) and the double peak of the line profiles, are in the range of 10 to $45\;kms^{-1}$. The expansion velocities imply a shell structure with an accelerated nebular gas. We also derived abundances from the permitted lines of CII, CIII, NII, NIII, OII, and OIII, which may have been formed through the fluorescence mechanism. NGC 6210 is likely to be evolved from a progenitor of more than $3M_{\bullet}$, which had been born near the Galactic plane.

• Journal of Astronomy and Space Sciences
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• 제21권2호
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• pp.109-120
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• 2004

2003년 9월 발사된 과학기술위성 1호의 탑재체 원자외선 분광기(FIMS)기는 우주 및 오로라 관측을 주 임무로 하고있다. 본 논문에서는 원자외선 분광기의 성공적인 천문 관측을 지원하기 위해, 탑재 컴퓨터와 원자외선 분광기와의 간단하고 신뢰성 있는 시간 동기화 기법을 소개한다. 이것은 과학기술위성 1호라는 특별한 환경 하에서 위성의 신뢰성을 줄이지 않으면서 시간 동기화를 이루도록 고안된 방법이다. 정확도가 서로 다른 두 가지 방법이 제시되었으며, 주된 방법을 사용할 수 없을 때 정확도가 낮은 방법을 사용함으로써 고장에 대처할 수 있도록 하였다. 이 기법들은 위성 시스템의 변경을 최소화하고 간단한 회로를 사용함으로써 구현에 따른 비용을 절감하고 고도의 신뢰성을 유지하도록 설계되었다.

• 한국임상수의학회지
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• 제19권2호
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• pp.191-194
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• 2002

The nursing vocalization of domestic pigs(Landrace$\times$Yorkshire) was investigated with respect to common features. All vocalizations uttered during nursings in 5 sows at 5 days after farrowing were recorded and 305 grunts were processed in a spectrograph. The sow's repeated grunting during nursing can be regarded as a contact call and a signal of the mother to start and synchronize the suckling behavior of the piglets. Analysis in the time domain revealed the gross structure of the call, whereas in the frequency domain the fine structure of single grunts was investigated. Nursing interval, duration of nursing behavior, duration of grunt, grunt rate per 10 seconds, fundamental frequency, 1 formant, 2 formant, 3 formant, 4 formant and spectrum were investigated. The results showed that mean interval between the nursing following one another was 25, 4.6 min and duration of nursing behavior was 3.2 $\pm$ 0.7 min. Average duration of grunt was 203.9 $\pm$ 63.6 ms. The formant contours could be identified. The nursing behavior might be disturbed by the grunts of alien sow.

• 음성과학
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• 제4권2호
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• pp.115-139
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• 1998

The aim of this study is to develop an the assessment program for the singing voice which is based on the physiological and acoustic methods. 22 sopranos, 6 mezzo sopranos, 4 tenors and 4 baritones participated to these experiments. The results measured by Visi-Pitch, spectrograph, and strobo-scope can be summarized as follows: (1) The maximum phonation time of singers must over 14 second higher with one deep inspiration (2) The parts classified by vocal range using Visi-Pitch: soprano between 167Hz $\sim$1,190Hz, mezzo soprano between 146Hz$\sim$956Hz, tenor between 75Hz$\sim$503Hz and baritone between 73 Hz and 385 Hz. (3) Longitudinal glottal size of singers decreases depending on the high-low pitch variation while lattitudinal glottal size increases depending on high-low pitch variation. (4) Well-trained singers show over 5 times the vibrato rate of untrained singers and regular pitch variation during measured periods. Vibrato's intensity do not over 3 dB. (5) Singer's formant indicates professional voice depending on the each parts: 3,207 Hz for soprano, 3,057 Hz for mezzo soprano, 2,754 Hz for tenor and 2,560 Hz for baritone.. (6) $F_1$ of singing voice is higher than that of speech while $F_2\;and\;F_3$ of singing voice are lower than those of speech.