THE CHEMICAL PROPERTIES OF LOW-REDSHIFT QSOs

Journal Article · Sun Jan 20 04:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/763/1/58· OSTI ID:22167182

Shin, Jaejin; Woo, Jong-Hak ^[1]; Nagao, Tohru ^[2]; Kim, Sang Chul ^[3]

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1. Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)
2. The Hakubi Center for Advanced Research, Kyoto University, Yoshida-Ushinomiya-cho, Sakyo-ku, Kyoto 606-8302 (Japan)
3. Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

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.

• OSTI ID: 22167182
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 763; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
BLACK HOLES
CARBON IONS
CHEMICAL PROPERTIES
COMPARATIVE EVALUATIONS
CORRELATIONS
ELEMENT ABUNDANCE
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
LUMINOSITY
METALS
PHOTON EMISSION
QUASARS
RED SHIFT
SILICON IONS
TELESCOPES
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA