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Ionized Gas Outflows in Infrared-bright Dust-obscured Galaxies Selected with<i>WISE</i>and SDSS
Toba, Yoshiki,Bae, Hyun-Jin,Nagao, Tohru,Woo, Jong-Hak,Wang, Wei-Hao,Wagner, Alexander Y.,Sun, Ai-Lei,Chang, Yu-Yen American Astronomical Society 2017 The Astrophysical journal Vol.850 No.2
<P>We present the ionized gas properties of infrared (IR)-bright dust-obscured galaxies (DOGs) that show an extreme optical/IR color, (i - [22])(AB) > 7.0, selected with the Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE). For 36 IR-bright DOGs that show [O III]lambda 5007 emission in the SDSS spectra, we performed a detailed spectral analysis to investigate their ionized gas properties. In particular, we measured the velocity offset (the velocity with respect to the systemic velocity measured from the stellar absorption lines) and the velocity dispersion of the [O III] line. We found that the derived velocity offset and dispersion of most IR-bright DOGs are larger than those of Seyfert 2 galaxies (Sy2s) at z < 0.3, meaning that the IR-bright DOGs show relatively strong outflows compared to Sy2s. This can be explained by the difference in IR luminosity contributed from active galactic nuclei, LIR (AGN), because we found that (i) L(IR ()AGN) correlates with the velocity offset and dispersion of [O III] and (ii) our IR-bright DOG sample has larger L-IR (AGN) than Sy2s. Nevertheless, the fact that about 75% IR-bright DOGs have a large (> 300 km s(-1)) velocity dispersion, which is a larger fraction compared to other AGN populations, suggests that IR-bright DOGs are good laboratories to investigate AGN feedback. The velocity offset and dispersion of [O III] and [Ne III]lambda 3869 are larger than those of [O II]lambda 3727, which indicates that the highly ionized gas tends to show stronger outflows.</P>
THE CHEMICAL PROPERTIES OF LOW-REDSHIFT QSOs
Shin, Jaejin,Woo, Jong-Hak,Nagao, Tohru,Kim, Sang Chul IOP Publishing 2013 The Astrophysical journal Vol.763 No.1
<P>We investigate the chemical properties of low-z QSOs, using archival UV spectra obtained with the Hubble Space Telescope and International Ultraviolet Explorer for a sample of 70 Palomar-Green QSOs at z < 0.5. By utilizing the flux ratios of UV emission lines (i.e., N V/C IV, (Si IV+O IV])/C IV, and N V/He II) as metallicity indicators, we compare broad-line region (BLR) gas metallicity with active galactic nucleus (AGN) properties, i.e., black hole (BH) mass, luminosity, and Eddington ratio. We find that BLR metallicity correlates with Eddington ratio while the dependency on BH mass is much weaker. Although these trends of low-z AGNs appear to be different from those of high-z QSOs, the difference between low-z and high-z samples is partly caused by the limited dynamical range of the samples. We find that metal enrichment at the center of galaxies is closely connected to the accretion activity of BHs and that the scatter of metallicity correlations with BH mass increases over cosmic time.</P>
ERRATUM : 'LYMANα EMITTERS BEYOND REDSHIFT 5: THE DAWN OF GALAXY FORMATION' (JKAS, 36, 123, [2003])
Taniguchi, Yoshiaki,Shioya, Yasuhiro,Ajiki, Masaru,Fujita, Shinobu S.,Nagao, Tohru,Murayama, Takashi The Korean Astronomical Society 2003 Journal of The Korean Astronomical Society Vol.36 No.4
The first sentence in the second paragraph of INTRODUCTION, 'The first discovery of a galaxy beyond z=5 was reported by Weymann et al. (1998); HDF 4-470.3 at z=5.60.' should be read as 'The first discovery of a galaxy beyond z=5 was reported by Dey et al. (1998); 0140+326 RD1 at z=5.34'. The authors sincerely regret this error.
LYMANα EMITTERS BEYOND REDSHIFT 5: THE DAWN OF GALAXY FORMATION
TANIGUCHI YOSHIAKI,SHIOYA YASUHIRO,AJIKI MASARU,FUJITA SHINOBU S.,NAGAO TOHRU,MURAYAMA TAKASHI The Korean Astronomical Society 2003 Journal of The Korean Astronomical Society Vol.36 No.3
The 8m class telescopes in the ground-based optical astronomy together with help from the ultra-sharp eye of the Hubble Space Telescope have enabled us to observe forming galaxies beyond red shift z = 5. In particular, more than twenty Ly$\alpha$-emitting galaxies have already been found at z > 5. These findings provide us with useful hints to investigate how galaxies formed and then evolved in the early universe. Further, detailed analysis of Ly$\alpha$ emission line profiles are useful in exploring the nature of the intergalactic medium because the trailing edge of cosmic reionization could be close to z $\~$ 6 -7, at which forming galaxies have been found recently. We also discuss the importance of superwinds from forming galaxies at high redshift, which has an intimate relationship between galaxies and the intergalactic medium. We then give a review of early cosmic star formation history based on recent progress in searching for Ly$\alpha$-emitting young galaxies beyond red shift 5.