Young‐Jong Sohn

Near-infrared and K' images were used to investigate the stellar contents of the asymptotic giant branch (AGB) population in the nearby dwarf elliptical galaxy NGC 147. The obtained and color–magnitude diagrams contain stars of AGB and red giant branch populations, where the former consists of a group of bright blue stars, a dominant population of M giant and a red C star population. We identified 91 AGB C stars in NGC 147 with the mean absolute magnitude and colors of , and . The estimated numb

V, R, and I CCD images are used to investigate the photometric properties and spatial distribution of supergiants in the nearby interacting galaxy NGC 672. Not counting stars imbedded in H II regions, our sample consists of 237 objects. The (V - R, V - I) two-color diagram indicates that the majority of these stars have spectral types between A - K. Statistical tests show that the outer region of NGC 672 contains a redder population of supergiants than the inner region. Comparisons with theoreti

Departments of Anesthesiology and Clinical Pharmacology, University of Groningen, Groningen, The Netherlands, and Departments of Anesthesia and Pharmacology, University of California San Francisco, San Francisco, CA 94143

Using wide-field J, H, and Ks images obtained with the WIRCam near-infrared camera on the Canada–France–Hawaii Telescope, we investigated the spatial density configuration of stars within the tidal radius of metal-poor globular cluster NGC 6626, which is known to be located near the bulge region and have a thick-disk orbit motion. In order to trace the stellar density around a target cluster, we sorted the cluster's member stars using a mask-filtering algorithm and weighted the stars on the colo

We determined values of distance modulus to nearby dwarf galaxy NGC 185 from the Tip of Red-Giant Branch (TRGB) method. Apparent magnitudes of the TRGB are estimated from the near-infrared $JHK$ luminosity functions (LFs) of the resolved giant branch stars. Theoretical absolute magnitudes of the TRGB in near-infrared bands have been extracted from the Yonsei-Yale isochrones. The observed apparent and theoretical absolute magnitudes of the TRGB provide values of distance modulus to NGC 185 as $(m

The five space density distribution D(z) wish distance perpendicular to the Galactic plane were combined. The scale heights and the local densities at z = 0 of the thin disk, thick disk, and the halo components were estimated from the nonlinear least square fits of exponential law. The scale heights of the thin disk, thick disk, and the halo components were estimated to be <TEX>$260{\pm}90$</TEX> pc, <TEX>$660{\pm}220$</TEX> pc, and <TEX>$3.6{\pm}1.4$</TEX> kpc, respectively. The density ratio o

Abstract We report the multiband photometry of asteroids observed over 14 nights from 2015 December to 2017 December using the Korea Microlensing Telescope Network telescopes with the taxonomic classification of those objects. The data set contains the photometry of 6793 asteroids in the Sloan Digital Sky Survey griz bands. Following the method of DeMeo &amp; Carry, we define classification criteria on the 2D color plane to assign nine taxonomic types (A, B, C, K, L&amp;D, O, S, V, and X) for th

The <TEX>$JHK_S$</TEX> magnitudes of the red giant branch tip (TRGB) and the distance moduli of the nearby dwarf irregular galaxy IC 1613 have been determined from the near-infrared luminosity functions (LFs) of the resolved stars in the galaxy. Applying a Savitzky-Golay filtering, we derived the second derivatives of the LFs, and estimated the apparent magnitudes of the TRGB as <TEX>$m_J\;=\;19.1$</TEX>, <TEX>$m_H\;=\;18.4$</TEX>, and <TEX>$m_{Ks}\;=\;18.0$</TEX>. The mean values of the theoret

We report the distance modulus of nearby dwarf irregular galaxy NGC 6822 estimated from the so-called Tip of Red-giant Branch (TRGB) method. To detect the apparent magnitudes of the TRGB we use the color-magnitude diagrams (CMDs) and luminosity functions (LFs) in the near-infrared $JHK$ bands. Foreground stars, main-sequence stars, and supergiant stars have been classified on the $(g-K,g)$ plane and removed on the near-infrared CMDs, from which only RGB and AGB stars are remained on the CMDs and

We report the distance modulus of nearby dwarf irregular galaxy NGC 6822 estimated from the so-called Tip of Red-giant Branch (TRGB) method. To detect the apparent magnitudes of the TRGB we use the color-magnitude diagrams (CMDs) and luminosity functions (LFs) in the near-infrared JHK bands. Foreground stars, main-sequence stars, and supergiant stars have been classified on the (g - K, g) plane and removed on the near-infrared CMDs, from which only RGB and AGB stars are remained on the CMDs and

To derive the metallicities of M3 and M5, we used the shape of red giant branch, horizontal branch magnitude, and red giant branch bump on the (V - I) - V color magnitude diagrams. [Fe/H] values ranging -1.46 -1.69 for M3, and -1.00 -1.49 for M5 are estimated. This result leads the morpholgies of red giant and horizontal branches on the (V-I) - v color magnitude diagrams can be good indirect metallicity indicators of galactic globular clusters.