Christopher P. Ahn
A5004196096- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Adaptive optics and wavefront sensing
- Japanese History and Culture
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
University of Utah
2012-2019
ABSTRACT The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from Baryon Oscillation Spectroscopic (BOSS). This ninth release (DR9) of SDSS project includes 535,995 new galaxy spectra (median z ∼ 0.52), 102,100 quasar 2.32), and 90,897 stellar spectra, along with presented in previous releases. These were obtained BOSS spectrograph taken between 2009 December 2011 July. In addition, parameters pipeline, which determines radial velocities, surface temperatures,...
The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in clustering matter over a larger volume than combined efforts all previous spectroscopic surveys large-scale structure. BOSS uses 1.5 million luminous galaxies as faint i = 19.9 10,000 deg2 BAO redshifts z < 0.7. Observations neutral hydrogen Lyα forest more 150,000 quasar spectra (g 22) will constrain redshift range 2.15 3.5. Early results from include first detection...
The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the Tenth Public Data Release (DR10) from its current incarnation, SDSS-III. data release includes first spectroscopic Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with Baryon Oscillation Spectroscopic (BOSS) taken through 2012 July. APOGEE instrument is a near-infrared R ∼ 22,500 300 fiber spectrograph covering 1.514–1.696 μm. survey studying chemical abundances and radial...
We present a detailed study of the nuclear star clusters (NSCs) and massive black holes (BHs) four nearest low-mass early-type galaxies: M32, NGC205, NGC5012, NGC5206. measure dynamical masses both BHs NSCs in these galaxies using Gemini/NIFS or VLT/SINFONI stellar kinematics, Hubble Space Telescope (HST) imaging, Jeans Anisotropic Models. detect NGC5102, NGC5206, while we find only an upper limit. These BH mass estimates are consistent with previous measurements M32 those NGC5102 NGC5206...
Abstract We examine the internal properties of most massive ultracompact dwarf galaxy (UCD), M59-UCD3, by combining adaptive-optics-assisted near-IR integral field spectroscopy from Gemini/NIFS and Hubble Space Telescope ( HST ) imaging. use multiband imaging to create a mass model that suggests accounts for presence multiple stellar populations structural components. combine these models with kinematics measurements find best-fit mass-to-light ratio M / L black hole (BH) using Jeans...
The origin of ultracompact dwarfs (UCDs), a class compact stellar systems discovered two decades ago, still remains matter debate. Recent discoveries central supermassive black holes in UCDs likely inherited from their massive progenitor galaxies provide support for the tidal stripping hypothesis. At same time, on statistical grounds, some might be representatives high luminosity tail globular cluster function. Here we present detection $3.3^{+1.4}_{-1.2}\times10^6\,M_{\odot}$ hole ($1σ$...
We present the detection of supermassive black holes (BHs) in two Virgo ultracompact dwarf galaxies (UCDs), VUCD3 and M59cO. use adaptive optics assisted data from Gemini/NIFS instrument to derive radial velocity dispersion profiles for both objects. Mass models UCDs are created using multi-band Hubble Space Telescope (HST) imaging, including modeling mild color gradients seen then find a best-fit stellar mass-to-light ratio ($M/L$) BH mass by combining kinematic deprojected profile Jeans...
Abstract We improve the dynamical black hole (BH) mass estimates in three nearby low-mass early-type galaxies: NGC 205, 5102, and 5206. use new Hubble Space Telescope ( HST )/STIS spectroscopy to fit star formation histories of nuclei these galaxies, measurements create local color–mass-to-light ratio M/L ) relations. then models from imaging combined with adaptive optics kinematics, we Jeans constrain their BH masses. The masses central BHs 5102 5206 are both below one million solar...
Abstract The recent discovery of massive black holes (BHs) in the centers high-mass ultra-compact dwarf galaxies (UCDs) suggests that at least some are stripped nuclear star clusters galaxies. We present first study investigates whether such BHs, and therefore nuclei, also exist low-mass ( M < 10 7 ⊙ ) UCDs. constrain BH masses two UCDs located Centaurus A (UCD 320 UCD 330) using Jeans modeling resolved stellar kinematics from adaptive optics data obtained with SINFONI integral field...
Reviewed by: Literature, Modernity, and the Practice of Resistance: Japanese Taiwanese Fiction, 1960–1990 by Margaret Hillenbrand Sylvia Li-chun Lin (bio) Christopher Ahn Hillenbrand. 1960–1990. Edited Glen Dudbridge Frank Pieke. Chinese Studies, vol. 11. Leiden: E. J. Brill Academic Publishers, 2007. 370 pp. Hardcover $151.00, ISBN 978-90-04-15478-0. This is an ambitious project in which author proposes to study recent contemporary East Asian literature through intraregional episteme that...
BigBOSS is a Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with wide-area galaxy quasar redshift survey over 14,000 square degrees. It has been conditionally accepted by NOAO in response call for major new instrumentation high-impact science program 4-m Mayall telescope at Kitt Peak. The instrument robotically-actuated, fiber-fed spectrograph capable taking 5000 simultaneous spectra wavelength range from 340 nm 1060 nm,...