Probing the intermediate-age globular clusters in NGS 5128 from ultraviolet observations (2009)
Rey, Soo-Chang, Sohn, Sangmo T., Beasley, Michael A, Lee, Young-Wook, Rich, R. Michael, Yoon, Suk-Jin, ...
We explore the age distribution of the globular cluster (GC) system of the nearby elliptical galaxy NGC 5128 using ultraviolet (UV) photometry from GALEX observations, with UV–optical colors used...
Probing the Intermediate-Age Globular Clusters in NGC 5128 from Ultraviolet Observations (2009)
Rey, Soo-Chang, Sohn, Sangmo T., Beasley, Michael A., Lee, Young-Wook, Rich, R. Michael, Yoon, Suk-Jin, ...
We explore the age distribution of the globular cluster (GC) system of the nearby elliptical galaxy NGC 5128 using ultraviolet (UV) photometry from Galaxy Evolution Explorer (GALEX) observations,...
Choi, Yumi, Goto, Tomotsugu, Yoon, Suk-Jin
Strong Balmer absorption lines and the lack of Ha and [OII] emission lines signify that E+As are post-starburst systems. Recent studies suggest that E+As may undergo the transition from the `blue...
Compact stellar systems in the Fornax cluster: a UV perspective (2008)
Mieske, Steffen, Hilker, Michael, Bomans, Dominik J., Rey, Soo-Chang, Kim, Suk, Yoon, Suk-Jin, ...
In recent years, increasing evidence for chemical complexity and multiple stellar populations in massive globular clusters (GCs) has emerged, including extreme horizontal branches (EHBs) and UV...
Yoon, Suk-Jin, Joo, Seok-Joo, Ree, Chang H., Han, Sang-Il, Kim, Do-Gyun, Lee, Young-Wook
Despite the efforts of the past decade, the origin of the bimodal horizontal-branch (HB) found in some globular clusters (GCs) remains a conundrum. Inspired by the discovery of multiple stellar...
Ree, Chang H., Lee, Young-Wook, Yi, Sukyoung K., Yoon, Suk-Jin, Rich, R. Michael, Deharveng, Jean-Michel, ...
We present the GALEX UV photometry of the elliptical galaxies in Abell clusters at moderate redshifts (z < 0.2) for the study of the look-back time evolution of the UV upturn phenomenon. The...
GALEX Ultraviolet Photometry of Globular Clusters in M31: Three Year Results and a Catalog (2007)
Rey, Soo-Chang, Rich, R. Michael, Sohn, Sangmo T., Yoon, Suk-Jin, Chung, Chul, Yi, Sukyoung K., ...
We present ultraviolet (UV) photometry of M31 globular clusters (GCs) found in 23 Galaxy Evolution Explorer (GALEX) images covering the entirety of M31. We detect 485 and 273 GCs (and GC candidates)...
GALEX Ultraviolet Photometry of Globular Clusters in M31: Three Year Results and a Catalog (2006)
Rey, Soo-Chang, Rich, R. Michael, Sohn, Sangmo T., Yoon, Suk-Jin, Chung, Chul, Yi, Sukyoung K., ...
We present ultraviolet (UV) photometry of M31 globular clusters (GCs) found in 23 Galaxy Evolution Explorer (GALEX) images covering the entirety of M31. We detect 485 and 273 GCs (and GC candidates)...
UV Upturn in Elliptical Galaxies: Theory (2006)
Yi, Sukyoung K., Yoon, Suk-Jin
The UV upturn is the rising flux with decreasing wavelength between the Lyman limit and 2500\AA found virtually in all bright spheroidal galaxies. It has been a mystery ever since it was first...
Explaining the Color Distributions of Globular Cluster Systems in Elliptical Galaxies (2006)
Yoon, Suk-Jin, Yi, Sukyoung Ken, Lee, Young-Wook
The colors of globular clusters in most of large elliptical galaxies are bimodal. This is generally taken as evidence for the presence of two cluster subpopulations that have different geneses....
Lee, Young-Wook, Joo, Seok-Joo, Han, Sang-Il, Chung, Chul, Ree, Chang H., Sohn, Young-Jong, ...
Recent observations for the color-magnitude diagrams (CMDs) of the massive globular cluster Omega Centauri have shown that it has a striking double main sequence (MS), with a minority population of...
An Aligned Stream of Low-Metallicity Clusters in the Halo of the Milky Way (2002)
Yoon, Suk-Jin, Lee, Young-Wook
One of the long-standing problems in modern astronomy is the curious division of Galactic globular clusters, the "Oosterhoff dichotomy," according to the properties of their RR Lyrae stars. Here, we...
Omega Centauri as a Disrupted Dwarf Galaxy: Evidence from Multiple Stellar Populations (2001)
Lee, Young-Wook, Rey, Soo-Chang, Ree, Chang H., Joo, Jong-Myung, Sohn, Young-Jong, Yoon, Suk-Jin, ...
Our recent CCD photometry (Lee et al. 1999) has shown, for the first time, that omega Cen has several distinct stellar populations, which is reminiscent of the Sagittarius dwarf galaxy. Here we...
Ree, Chang H., Yoon, Suk-Jin, Rey, Soo-Chang, Lee, Young-Wook
We have constructed synthetic color-magnitude diagrams (CMDs) for omega Cen and other massive globular clusters with apparently peculiar CMD morphology. Our population models, which adopt the most...
CCD Photometry of the Classic Second Parameter Globular Clusters M3 and M13 (2001)
Rey, Soo-Chang, Yoon, Suk-Jin, Lee, Young-Wook, Chaboyer, Brian, Sarajedini, Ata
We present high-precision V, B-V color-magnitude diagrams (CMDs) for the classic second parameter globular clusters M3 and M13 from wide-field deep CCD photometry. The data for the two clusters were...
A New Distance Estimator and Spatial Distribution of GRBS Observed by BATSE (2001)
Chang, Heon-Young, Yoon, Suk-Jin, Choi, Chul-Sung
We propose a redshift estimator for the long ($T_{90} > 20$) gamma-ray bursts (GRBs) observed by the BATSE. It is based on an empirical relation between the redshift and the power-law index of power...
Horizontal-Branch Morphology as an Age Indicator (2001)
Lee, Young-Wook, Yoon, Suk-Jin, Rey, Soo-Chang, Chaboyer, Brian
We present our recent revision of model constructions for the horizontal-branch (HB) morphology of globular clusters, which suggests the HB morphology is more sensitive to age compared to our earlier...
Age Estimation of Extragalactic Globular Cluster Systems Using H beta Index (2001)
Lee, Hyun-chul, Yoon, Suk-Jin, Lee, Young-Wook
After taking into account, for the first time, the detailed systematic variation of horizontal-branch (HB) morphology with age and metallicity, our population synthesis models show that the...
Lee, Hyun-chul, Yoon, Suk-Jin, Lee, Young-Wook
The strength of the H$\beta$ index has been computed for the integrated spectra of model globular clusters from the evolutionary population synthesis. These models take into account, for the first...
Horizontal-Branch Stars as an Age Indicator (1999)
Lee, Young-Wook, Yoon, Suk-Jin, Lee, Hyun-chul, Woo, Jong-Hak
Surface temperature distribution of horizontal-branch (HB) stars is very sensitive to age in old stellar systems, which makes it an attractive age indicator. In this paper, we present the recent...