Detection of iron emission in the z = 5.74 QSO SDSSp J104433.04 - 012502.2

Kentaro Aoki, Takashi Murayama, Kiyomi Denda

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6 Citations (Scopus)


We obtained near-infrared spectroscopy of the z =5.74 QSO, SDSSp J104433.04-012502.2, with the Infrared Camera and Spectrograph of the Subaru Telescope. The redshift of 5.74 corresponds to a cosmological age of 1.0 Gyr for the current A-dominated cosmology. We found a similar strength of the Fe II (3000-3500 Å) emission lines in SDSSp J104433.04-012502.2 as in low-redshift QSOs. This is the highest redshift detection of iron. We subtracted a power-law continuum from the spectrum and fitted model Fe II emission and the Balmer continuum. The rest equivalent width of Fe II (3000-3500 Å) is ∼ 30 Å, which is similar to those of low-redshift QSOs measured in the same manner. The chemical-enrichment models that assume the lifetime of the progenitor of SNe Ia is longer than 1 Gyr predict that weaker Fe II emission in high-redshift (z > 3) QSOs than low-redshift ones. However, none of the observed high redshift QSOs show a systematic decrease of Fe II emission compared with low-redshift QSOs. This may be due to a shorter lifetime of SNe Ia in QSO nuclei than in the solar neighborhood. Another reason for the strong Fe II emission at z = 5.74 may be a longer cosmological age due to a smaller ωM.

Original languageEnglish
Pages (from-to)353-358
Number of pages6
JournalPublications of the Astronomical Society of Japan
Issue number3
Publication statusPublished - 2002
Externally publishedYes


  • Galaxies: active
  • Galaxies: quasars: emission lines
  • Galaxies: quasars: individual (SDSSp J104433.04-012502.2)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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