Age Dating of a High-Redshift QSO B1422+231 at [CLC][ITAL]z[/ITAL][/CLC] = 3.62and Its Cosmological Implications

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Abstract
The observed Fe II (UV+optical)/Mg II λλ2796, 2804 flux ratio from a gravitationally lensed quasar B1422+231 at z=3.62 is interpreted in terms of detailed modeling of photoionization and chemical enrichment in the broad-line region (BLR) of the host galaxy. The delayed iron enrichment by Type Ia supernovae is used as a cosmic clock. Our standard model, which matches the Fe II/Mg II ratio, requires the age of 1.5 Gyr for B1422+231 with a lower bound of 1.3 Gyr, which exceeds the expansion age of the Einstein-de Sitter Ω0=1 universe at a redshift of 3.62 for any value of the Hubble constant in the currently accepted range, H0=60-80 km s-1 Mpc-1. This problem of an age discrepancy at z=3.62 can be unraveled in a low-density Ω00.2 universe, either with or without a cosmological constant, depending on the allowable redshift range of galaxy formation. However, whether the cosmological constant is a required option in modern cosmology awaits a thorough understanding of line transfer processes in the BLRs.
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