title: Gas-rich galaxy pair unveiled in the lensed quasar 0957+561
abstract: Molecular gas in the host galaxy of the lensed quasar 0957+561 (QSO 0957+561) at the redshift of 1.41 has been detected in the carbon monoxide (CO) line. This detection shows the extended nature of the molecular gas distribution in the host galaxy and the pronounced lensing effects due to the differentially magnified CO luminosity at different velocities. The estimated mass of molecular gas is about 4 x 10(9) solar masses, a molecular gas mass typical 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 gas 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 lensed quasars can be used to improve the determination of the Hubble constant H(0).
authors.affiliation: Observatorio Astronomico Nacional (IGN), Apartado 1143, E-28800 Alcala de Henares, Spain. Institut de Radio Astronomie Millimetrique, F-38460 Saint Martin d'Heres, France. Instituto de Fisica de Cantabria (CSIC-UC), Facultad de Ci.
authors.initials: P
authors.lastname: Planesas
authors.initials: J
authors.lastname: Martin-Pintado
authors.initials: R
authors.lastname: Neri
authors.initials: L
authors.lastname: Colina