• Title/Summary/Keyword: AKARI

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LOST TIME: WHEN GIANTS ROAMED THE EARTH

  • Rowan-Robinson, Michael
    • Publications of The Korean Astronomical Society
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    • v.32 no.1
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    • pp.1-4
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    • 2017
  • Some after-dinner thoughts on the giants of infrared space astronomy. I here describe important events in infrared astronomy starting from 1964 when I started working on my PhD. Here I describe how I became involved in IRAS, Infrared Space Observatrory (ISO), Herschel, Spitzer and AKARI, together with important events that led to these great missions.

Mid-IR Luminosity Functions of Local Galaxies in the North Ecliptic Pole Field

  • Kim, Seong Jin;Lee, Hyung Mok;Jeong, Woong-Seob
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.72.3-72.3
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    • 2015
  • We present the mid-infrared (MIR) luminosity function (LF) of local (z < 0.3) star forming (SF) galaxies based on the AKARI's NEP-Wide Survey data. We utilized a combination of the NEP-Wide point source catalogue containing a large number (114,000) of infrared (IR) sources distributed over the wide (5.4 sq. deg) field and spectroscopic redshift (z) data for 1790 selected targets obtained by optical follow-up surveys with MMT/Hectospec and WIYN/Hydra. The AKARI's continuous $2{\sim}24{\mu}m$ wavelength coverage and the spectroscopic redshifts for sample galaxies enable us to derive accurate spectral energy distributions (SEDs) in the mid-infrared. We carried out SED-fit analysis and employed 1/Vmax method to derive the mid-IR (e.g., $8{\mu}m$, $12{\mu}m$, and $15{\mu}m$ rest-frame) luminosity functions. Our results for local galaxies from the NEP region generally consistent with various previous works for other fields over wide luminosity ranges. The comparison with the results of the NEP-Deep data implies the luminosity evolution from higher redshifts towards the present epoch. We attempted to fit our derived LFs to the double power-laws and present the resulting power indices. We also examined the correlation between mid-IR luminosity and total IR luminosity.

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SYSTEMATIC STUDY OF INTERSTELLAR ICES IN NEARBY GALAXIES

  • Yamagishi, M.;Kaneda, H.;Oyabu, S.;Ishihara, D.;Onaka, T.;Shimonishi, T.;Suzuki, T.
    • Publications of The Korean Astronomical Society
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    • v.27 no.4
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    • pp.249-252
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    • 2012
  • The absorption features due to interstellar ices, especially $H_2O$ and $CO_2$ ices, provide us with crucial information on present and past interstellar environments, and thus the evolutionary histories of galaxies. Before AKARI, however, few detections of ices were reported for nearby galaxies. The AKARI's unique capability of near-infrared spectroscopy with high sensitivity enables us to systematically study ices in nearby galaxies. Thus we have explored many near-infrared spectra ($2.5-5{\mu}m$) of the 211 pointed observations, searching for the absorption features of ices. As a result, out of 122 nearby galaxies, we have significantly detected $H_2O$ ice from 36 galaxies and $CO_2$ ice from 9 galaxies. It is notable that the ices are detected not only in late-type galaxies but also in early-type galaxies. We find that $CO_2$ ice is more compactly distributed near the galactic center than $H_2O$ ice. Finally, we suggest that the gas density of a molecular cloud and UV radiation may be important factors to determine the abundance of ices.