• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.78.2-78.2
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• 2015

Powered by a supermassive black hole, active galactic nuclei (AGNs) are characterized by prominent emission lines including Blamer lines. The unification scheme of AGNs requires the existence of a thick molecular torus that may hide the broad emission line region. In this configuration, it is expected that the far UV radiation from the central engine can be Raman scattered by neutral hydrogen to reappear around Balmer lines which can be identified observationally with broad Balmer wings. Another mechanism that can form Balmer wings is considered by invoking a fast moving medium around the central engine. In this presentation, we produce Balmer wings that are formed through Raman scattering and also those expected from a fast moving emission flow. It is noted that Raman Balmer wings exhibit stronger red part whereas the opposite behavior is seen in the Balmer wings obtained from a fast moving emission flow.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.84.2-84.2
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• 2010

Radial changes of stellar population within the Galactic globular clusters have been reported in many spectroscopic and photometric studies. We present new integrated spectroscopic data for 24 Galactic globular clusters and have measured line indices within various aperture sizes. Radial gradients have been investigated for the Balmer lines and metal lines (Mgb). Our results show an increase in the strength of the Balmer lines toward the centres in some clusters including NGC7078, NGC7089, and NGC6934, in which colour gradients also have been detected previously. However, some other clusters show little trend or even an increase toward the outskirt in the Balmer lines. Metal sensitive lines generally have an anti-correlation with the Balmer lines. We discuss possible stellar populations being responsible for the radial change in line indices.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.148.2-148.2
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• 2011

Many symbiotic stars exhibit features formed through Raman scattering with hydrogent atom, which can be useful in probing the mass loss and mass transfer processes. These include Raman scattered O VI 6830, 7088, Raman scattered He II 6545, 4850, 4332, and broad wings around Balmer emission lines. In this study we investigate the basic properties of broad Balmer wings formed through Raman scattering using a Monte Carlo technique. Special attention is made on the symmetry of the wings which is expected to be broken due to asymmetric scattering cross section. In this poster, we show preliminary results.

• Journal of The Korean Astronomical Society
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• v.28 no.1
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• pp.77-87
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• 1995

An attempt has been made to analyze time series of $H_\alpha,\;H_\beta,\;and\; H_\gamma$ line profiles taken from a 3B/X6.1 flare which occurred on Oct. 27, 1991 in an active region, NOAA 6891. A total of 22 sets of $H_\alpha,\;H_\beta,\;and\; H_\gamma$ taken with a low and non-uniform time resolution of 10-40 seconds were scanned by PDS with absolute intensity calibration to derive the physical characteristics of the material in the flare chromosphere. Our . results are as follows: (1) The lower Balmer lines observed during the flare activity are broadened by Stark effect. (2) At the peak of the flare activity, the electron temperature of the Balmer line emitting region reaches up to 35000K and its geometrical thickness increases to a scale of $10^4km$, suggesting that high energy particles penetrate deep into the photospheric level.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.80-80
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• 2010

About 50% of Active Galactic Nuclei(AGNs) are found to be red and dust-obscured. They are believed to be in an early dusty stage of AGNs evolution or affected by dust torus in the direction of line of sight. However, optical spectrum is affected by dust extinction, making it difficult to study their properties, such as FWHM and luminosity. In order to reveal the mass of central Black Hole(BH) in red AGN, we establish a new BH mass estimator for typical type1 AGNs using Near InfraRed(NIR) hydrogen line($P_{\alpha}$ and $P_{\beta}$), since these lines are at longer wavelength, less affected by dust extinction than optical hydrogen lines, such as $H_{\alpha}$ and $H_{\alpha}$. To derive the new empirical formula, we use a sample of well-known 36 AGN with a wide BH mass range of $10^6-10^9\;M_{\odot}$, where $M_{BH}s$ are estimated by reverberation mapping method and single epoch method. The $P_{\alpha}/P_{\beta}$ luminosities and FWHMs are derived by analyzing IRTF NIR spectra or taken from literature values. We show that luminosities and FWHMs of these lines correlate well with those of Balmer lines. Suggesting that Paschen and Balmer broad lines are originated from same region. Finally, we present the new $M_{BH}$ formula that are based on $P_{\alpha}/P_{\beta}$ luminosity and FWHM. We hope that our result will be used for investigating red AGNs.

• Journal of Astronomy and Space Sciences
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• v.9 no.1
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• pp.97-110
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• 1992

Observed spectra of the long period eclipsing binary VV Cephei show emission features of Balmer and some ionized metal lines. These features were interpreted as the result of the extended envelope activity surrounding the secondary star. Radial velocities and equivalent widths were calculated from some metal lines.

• The Bulletin of The Korean Astronomical Society
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• v.20
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• pp.29.1-29.1
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• 1995

• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.65.2-65.2
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• 2009

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.86.4-87
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• 2017

Symbiotic stars are binary systems composed of a hot white dwarf and a mass losing giant. Many symbiotic stars are known to exhibit broad wings around Balmer emission line. We show high resolution spectra of S-type symbiotic stars, Z Andromedae and AG Draconis, obtained with the ESPaDOnS and the 3.6 m Canada-France-Hawaii Telescope, in which we find prominent broad wings around Balmer lines. We adopt Monte-Carlo technique to consider two types of wing formation mechanisms, which are Thomson scattering by free electron in H II region and Raman scattering by atomic hydrogen in H I region. We find that Thomson wings of $H{\alpha}$ and $H{\beta}$ have the same widths in the Doppler space due to the cross section independent of wavelength. In contrast, Raman $H{\alpha}$ wings are 3 times broader widths than $H{\beta}$ counterparts, which is attributed to the different cross sections and branching ratios. Our CFHT data show that $H{\alpha}$ wings of Z Andromedae and AG Draconis are broader than $H{\beta}$ wings, lending strong support to the Raman scattering origin of Balmer wings in these objects.

• Bulletin of the Korean Space Science Society
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• 2009.04a
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• pp.36.4-37
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• 2009