Kyuseok Oh
Yonsei University
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Featured researches published by Kyuseok Oh.
Astrophysical Journal Supplement Series | 2012
Seulhee Oh; Kyuseok Oh; Sukyoung K. Yi
Galactic bars are often suspected to be channels of gas inflow to the galactic center and to trigger central star formation and active galactic nucleus (AGN) activity. However, the current status on this issue based on empirical studies is unsettling, especially regarding AGNs. We investigate this question based on the Sloan Digital Sky Survey Data Release 7. From the nearby (0.01 < z < 0.05) bright (M r < –19) database, we have constructed a sample of 6658 relatively face-on late-type galaxies through visual inspection. We found 36% of them to have a bar. Bars are found to be more common in galaxies with earlier morphology. This makes sample selection critical. Parameter-based selections would miss a large fraction of barred galaxies of early morphology. Bar effects on star formation or AGNs are difficult to understand properly because multiple factors (bar frequency, stellar mass, black hole mass, gas contents, etc.) seem to contribute to them in intricate manners. In the hope of breaking these degeneracies, we inspect bar effects for fixed galaxy properties. Bar effects on central star formation seem higher in redder galaxies. Bar effects on AGNs on the other hand are higher in bluer and less massive galaxies. These effects seem more pronounced with increasing bar length. We discuss possible implications in terms of gas contents, bar strength, bar evolution, fueling timescale, and the dynamical role of supermassive black hole.
European Radiology | 1998
Kyuseok Oh; Joo Hee Kim; S. H. Kook
Abstract. The aim of our study was to evaluate radiologic findings of the tuberculosis involving breast. We evaluated the radiologic features of 17 patients (18 lesions) with tuberculous disease involving the breast. The radiologic examinations, including mammography (16 patients), ultrasonography (12 patients), and Gd-DTPA-enhanced dynamic MRI (6 patients), were analyzed. Mammographic findings included mass (12 of 17 lesions), calcification (3 of 17 lesions), asymmetric density with spiculated margin (5 of 17 lesions), and axillary lymph node enlargement (8 of 17 lesions). On ultrasonography, a smooth bordered mass (7 of 13 lesions) with thin boundary (7 of 13 lesions) and heterogeneous, intermediate internal echoes (9 of 13 lesions) were most commonly demonstrated. On Gd-DTPA-enhanced dynamic MRI, 3 lesions showed significant enhancement at the first minute after injection (3 of 7 lesions). The maximun enhancing amount was greater than 500 normalized units, and the enhancing pattern was smooth or irregular ring appearance. Breast involvement with tuberculosis is rare but should be considered in the differential diagnosis of a woman living in an endemic area or when extramammary foci of tuberculosis are present. A multimodality imaging approach with clinical evaluation will help to establish the diagnosis of tuberculosis involving breast.
Monthly Notices of the Royal Astronomical Society | 2015
Lia F. Sartori; Kevin Schawinski; Ezequiel Treister; Benny Trakhtenbrot; Michael Koss; Maryam Shirazi; Kyuseok Oh
We investigated AGN activity in low-mass galaxies, an important regime that can shed light onto BH formation and evolution, and their interaction with their host galaxies. We identified 336 AGN candidates from a parent sample of
Monthly Notices of the Royal Astronomical Society | 2015
Simon Berney; Michael Koss; Benny Trakhtenbrot; C. Ricci; Isabella Lamperti; Kevin Schawinski; M. Baloković; D. Michael Crenshaw; T. C. Fischer; Neil Gehrels; Fiona A. Harrison; Yasuhiro Hashimoto; Kohei Ichikawa; R. F. Mushotzky; Kyuseok Oh; Daniel Stern; Ezequiel Treister; Yoshihiro Ueda; Sylvain Veilleux; Lisa M. Winter
\sim 48,000
The Astrophysical Journal | 2012
Stacy H. Teng; Kevin Schawinski; C. Megan Urry; Dan W. Darg; Sugata Kaviraj; Kyuseok Oh; Erin Wells Bonning; Carolin N. Cardamone; William C. Keel; Chris Lintott; Brooke Simmons; Ezequiel Treister
nearby low-mass galaxies (
Astrophysical Journal Supplement Series | 2015
Kyuseok Oh; Sukyoung K. Yi; Kevin Schawinski; M. Koss; Benny Trakhtenbrot; Kurt T. Soto
M_{\rm \star} \leq 10^{9.5}M_\odot
The Astrophysical Journal | 2017
M. Koss; Benny Trakhtenbrot; C. Ricci; Isabella Lamperti; Kyuseok Oh; Simon Berney; Kevin Schawinski; M. Baloković; Linda Baronchelli; D. Michael Crenshaw; T. C. Fischer; Neil Gehrels; Fiona A. Harrison; Yasuhiro Hashimoto; Drew Hogg; Kohei Ichikawa; Nicola Masetti; R. F. Mushotzky; Lia F. Sartori; Daniel Stern; Ezequiel Treister; Yoshihiro Ueda; Sylvain Veilleux; Lisa M. Winter
,
Nature | 2017
C. Ricci; Benny Trakhtenbrot; M. Koss; Yoshihiro Ueda; Kevin Schawinski; Kyuseok Oh; Isabella Lamperti; R. F. Mushotzky; Ezequiel Treister; Luis C. Ho; Anna K. Weigel; F. E. Bauer; Stephane Paltani; Andrew C. Fabian; Yanxia Xie; Neil Gehrels
z < 0.1
Monthly Notices of the Royal Astronomical Society | 2016
O. Ivy Wong; M. Koss; Kevin Schawinski; A. D. Kapińska; Isabella Lamperti; Kyuseok Oh; C. Ricci; Simon Berney; Benny Trakhtenbrot
) in the SDSS. We selected the AGN using the classical BPT diagram, a similar optical emission line diagnostic based on the HeII
Monthly Notices of the Royal Astronomical Society | 2017
Benny Trakhtenbrot; C. Ricci; M. Koss; Kevin Schawinski; R. F. Mushotzky; Yoshihiro Ueda; Sylvain Veilleux; Isabella Lamperti; Kyuseok Oh; Ezequiel Treister; Daniel Stern; Fiona A. Harrison; M. Baloković; Neil Gehrels
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