New near-infrared spectroscopy of the high-redshift quasar, B1422+231 at z=3.62

Citation
T. Murayama et al., New near-infrared spectroscopy of the high-redshift quasar, B1422+231 at z=3.62, ASTRONOM J, 117(4), 1999, pp. 1645-1650
Citations number
26
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMICAL JOURNAL
ISSN journal
00046256 → ACNP
Volume
117
Issue
4
Year of publication
1999
Pages
1645 - 1650
Database
ISI
SICI code
0004-6256(199904)117:4<1645:NNSOTH>2.0.ZU;2-4
Abstract
We present new near-infrared (rest-frame UV-to-optical) spectra of the high -redshift, gravitationally lensed quasar B1422 + 231 (z = 3.62). Diagnostic emission lines of Fe II, O III lambda 5007, and H beta, commonly used to d etermine the excitation, ionization, and chemical abundances of radio-quiet and radio-loud quasars, were detected. Our new data show that the ratio Fe I (UV)/H beta = 18.1 + 4.6 and Fe II: (optical)/H beta = 2.3 +/- 0.6 are h igher than those reported by Kawara et al. by factors of 1.6 and 3.3, respe ctively, although the ratio [O III] lambda 5007/H beta = 0.19 + 0.02 is nea rly the same between the two measurements. The discrepancy of the line flux ratios between the measurements is likely due to improved data and fitting procedures rather that to intrinsic variability. While approximately half of the high-z quasars observed to date have much more extreme Fe II (optica l)/H beta ratios, the line ratio measured for B1422 + 231 are consistent wi th the observed range of Fe rr (optical) ratios of low-z quasars.