Gas-rich galaxy pair unveiled in the lensed quasar 0957+561

Molecular gas in the host galaxy of the Lensed quasar 0957+561 (QSO 0957+56 1) at the redshift of 1.41 has been detected in the carbon monoxide (CO) Li ne. This detection shows the extended nature of the molecular gas distribut ion in the host galaxy and the pronounced lensing effects due to the differ entially magnified CO Luminosity at different velocities. The estimated mas s of molecular gas is about 4 x 10(9) solar masses, a molecular gas mass ty pical of a spiral galaxy Like the Milky Way. A second, weaker component of CO is interpreted as arising from a close companion galaxy that is rich in molecular gas and has remained undetected so far. Its estimated molecular g as mass is 1.4 x 10(9) solar masses, and its velocity relative to the main galaxy is 660 kilometers per second. The ability to probe the molecular gas distribution and kinematics of galaxies associated with high-redshift Lens ed quasars can be used to improve the determination of the Hubble constant H-0.