The Absorption Spectra of Q1107+487 and Q1442+295

Abstract

We present the first moderate resolution (≃ 40–120 km s⁻¹) spectroscopic observations of the bright (V ≤ 16.7) high-redshift QSOs Q1107+487 (z _em = 2.965) and Q1442+295 (z _em = 2.669) (Sanduleak & Pesch 1989). The relatively high signal to noise reached in the spectra along with an extensive wavelength coverage of the Lyα and the Lyβ forest allowed us to obtain, through profile fitting, column densities and Doppler parameters of the Lyman clouds towards these QSOs. The spectral coverage of regions longward of the Lya emission line of the QSOs at the expected wavelengths of CIV λλ1548,1550 at the redshifts of the Lyα forest allowed us to identify some heavy element absorption systems (hereafter HEASs) towards these QSOs. We have found no Lyman absorption system or HEAS towards these QSOs for which our data allow a deuterium measurement or to provide an interesting upper limit for the D/H ratio. The reason for this is that the Lyman lines with high column density detected towards these QSOs belong to absorption systems showing velocity structure.