Seoul National University Camera II (SNUCAM-II): The New SED Camera for the Lee Sang Gak Telescope (LSGT)

We present the characteristics and the performance of the new CCD camera system, SNUCAM-II (Seoul National University CAMera system II) that was installed on the Lee Sang Gak Telescope (LSGT) at the Siding Spring Observatory in 2016. SNUCAM-II consists of a deep depletion chip covering a wide wavelength from 0.3 {\mu}m to 1.1 {\mu}m with high sensitivity (QE at > 80% over 0.4 to 0.9 {\mu}m). It is equipped with the SDSS ugriz filters and 13 medium band width (50 nm) filters, enabling us to study spectral energy distributions (SEDs) of diverse objects from extragalactic sources to solar system objects. On LSGT, SNUCAM-II offers 15.7 {\times} 15.7 arcmin field-of-view (FOV) at a pixel scale of 0.92 arcsec and a limiting magnitude of g = 19.91 AB mag and z=18.20 AB mag at 5{\sigma} with 180 sec exposure time for point source detection.Comment: 8 pages, 9 figures, 4 tables, published in 2017 June issue of JKA

A Y-band look of the sky with 1-m class telescopes

Y -band is a broad passband that is centered at ~ 1 micron. It is becoming a new, popular window for extragalactic study especially for observation of red objects thanks to recent CCD technology developments. In order to better understand the general characteristics of objects in Y -band, and to investigate the promise of Y -band observations with small telescopes, we carried out imaging observation of several extragalactic fields, brown dwarfs and high redshift quasars with Y -band filter at the Mt. Lemmon Optical Astronomy Observatory and the Maidanak observatory. From our observations, we constrain the bright end of the galaxy and the stellar number counts in Y -band. Also, we test the usefulness of high redshift quasar (z > 6) selection via i-z-Y color-color diagram, to demonstrate that the i-z-Y color-color diagram is effective for the selection of high redshift quasars even with a conventional optical CCD camera installed at a 1-m class telescope.Comment: 12 pages, 6 figures, accepted for publication in JKA

The Spatial Dimension Of Take-Offs And Sustainability: The Case Of East Asian Countries

This study examines the relationship between the size of a country and its “take-off” for economic development. We find that most countries which experienced economic upheavals in the past decades are relatively small in terms of area. Specifically, take-offs appear to be quicker for smaller landmasses with larger potential workforce and higher population density, controlled for financial markets maturity, corporate governance, economic openness, and human capital development. We also find that take-offs are not sustainable by nature as most countries in East Asia that which experience take-offs are currently facing slow-downs of their economies. Through this finding, we predict that China may experience a slow-down at around 36% and may reach to the 50-60% of income level of the U.S.