Yoon Chan Taak

DISCOVERY OF A FAINT QUASAR AT z ∼ 6 AND IMPLICATIONS FOR COSMIC REIONIZATION

Recent studies suggest that faint active galactic nuclei may be responsible for the reionization of the universe. Confirmation of this scenario requires spectroscopic identification of faint quasars (

The Infrared Medium-Deep Survey. II. How to Trigger Radio AGNs? Hints from their Environments

M_{1450}>-24

The Infrared Medium-deep Survey. III. Survey of Luminous Quasars at 4.7 ≤ z ≤ 5.4

mag) at

The Infrared Medium-deep Survey. IV. The Low Eddington Ratio of A Faint Quasar at z ∼ 6: Not Every Supermassive Black Hole is Growing Fast in the Early Universe

z \gtrsim6

UNVEILING THE PROPERTIES OF FLS 1718+59: A GALAXY-GALAXY GRAVITATIONAL LENS SYSTEM

, but only a very small number of such quasars have been spectroscopically identified so far. Here, we report the discovery of a faint quasar IMS J220417.92+011144.8 at z~6 in a 12.5 deg

NEWLY DISCOVERED FOOTPRINTS OF GALAXY INTERACTION AROUND SEYFERT 2 GALAXY NGC 7743

^{2}

DISCOVERY OF A SUPERCLUSTER AT z ∼ 0.91 AND TESTING THE ΛCDM COSMOLOGICAL MODEL

region of the SA22 field of the Infrared Medium-deep Survey (IMS). The spectrum of the quasar shows a sharp break at

Medium-resolution Optical and Near-infrared Spectral Atlas of 16 2MASS-selected NIR-red Active Galactic Nuclei at z ∼ 0.3

\sim8443~\rm{\AA}

Photometric Reverberation Mapping with SQUEAN

, with emission lines redshifted to

UNVEILING THE PROPERTIES OF FLS 1718+59

z=5.944 \pm 0.002