Kuenley Chiu

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We have compiled L (3.4–4.1 μm) and M ′ (4.6–4.8 μm) photometry of 63 single and binary M, L, and T dwarfs obtained at the United Kingdom Infrared Telescope using the Mauna Kea Observatory (MKO) filter set. This compilation includes new L measurements of 8 L dwarfs and 13 T dwarfs and new M ′ measurements of 7 L dwarfs, 5 T dwarfs, and the M1 dwarf Gl 229A.(More)
We present the final spectroscopic QSO catalogue from the 2dF-SDSS LRG (luminous red galaxy) and QSO (2SLAQ) survey. This is a deep, 18 < g < 21.85 (extinction corrected), sample aimed at probing in detail the faint end of the broad line active galactic nuclei luminosity distribution at z 2.6. The candidate QSOs were selected from SDSS photometry and(More)
We present cosmological results from the statistics of lensed quasars in the Sloan Digital Sky Survey (SDSS) Quasar Lens Search. By taking proper account of the selection function, we compute the expected number of quasars lensed by early-type galaxies and their image separation distribution assuming a flat universe, which is then compared with 7 lenses(More)
We measure the ages, stellar masses, and star formation histories of z ∼ 6 galaxies, observed within 1Gyr of the Big Bang. We use imaging from the Hubble Space Telescope (HST) and the Spitzer Space Telescope from the public “Great Observatories Origins Deep Survey” (GOODS), coupled with ground-based near-infrared imaging, to measure their spectral energy(More)
We analyse recently acquired near-infrared Hubble Space Telescope imaging of the Great Observatories Origins Deep Survey (GOODS)-South field to search for star-forming galaxies at z ≈ 7.0. By comparing Wide Field Camera 3 (WFC3) 0.98μm Y-band images with Advanced Camera for Surveys (ACS) z-band (0.85μm) images, we identify objects with colours consistent(More)
We have searched for star-forming galaxies at z≈ 7–10 by applying the Lyman-break technique to newly released Y-, Jand H-band images (1.1, 1.25 and 1.6 μm) from Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. By comparing these images of the Hubble Ultra Deep Field with the Advanced Camera for Surveys (ACS) z′-band (0.85 μm) images, we identify(More)
We have resolved the newly discovered T dwarf SDSS J153417.05+161546.1 into a 0.11 binary using the Keck sodium laser guide star adaptive optics system. With an integrated-light near-IR spectral type of T3.5±0.5, this binary provides a new benchmark for studying the distinctive J-band brightening previously noted among early and mid-T dwarfs, using two(More)
We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46,420 quasars from the SDSS Data Release 3 (∼4188 deg2), we select a subsample of 22,683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic(More)
We study the recently discovered gravitational lens SDSS J1004+4112, the first quasar lensed by a cluster of galaxies. It consists of four images with a maximum separation of 14.62. The system was selected from the photometric data of the Sloan Digital Sky Survey (SDSS), and has been confirmed as a lensed quasar at z = 1.734 on the basis of deep imaging and(More)
Gravitational lensing is a powerful tool for the study of the distribution of dark matter in the Universe. The cold-dark-matter model of the formation of large-scale structures (that is, clusters of galaxies and even larger assemblies) predicts the existence of quasars gravitationally lensed by concentrations of dark matter so massive that the quasar images(More)