Q0957+561 revised: CO emission from a disk at z = 1.4^*

¹ I. Physikalisches Institut, University of Cologne, Zülpicherstr. 77, 50937 Köln, Germany e-mail: krips@ph1.uni-koeln.de
² Institut de Radio Astronomie Millimétrique, 300 rue de la Piscine, 38406 Saint Martin d'Hères, France
³ Instituto de Estructura de la Materia (CSIC), Serrano 121, 28006 Madrid, Spain
⁴ Observatorio Astronómico Nacional (IGN), Apartado 112, 28800 Alcalá de Henares, Spain

Received: 28 June 2004
Accepted: 19 October 2004

Abstract

Based on additional interferometric observations, we reanalysed the CO(2-1) and 3 mm continuum emission of Q0957+561, a lensed QSO at a redshift of . The emission in the CO(2-1) lines reveals a gas-rich host galaxy with a peculiar double-peaked profile at one of the two lensed images. Our new interferometric CO maps of the host galaxy agree well with HST images obtained by Keeton et al. (2000) and we thus argue that the two velocity components arise from molecular gas in the disk of the host galaxy. We also present new model calculations, all in excellent agreement with recent time delay measurements and simulations.