NEW OBSERVATIONS AND A NEW INTERPRETATION OF CO(3-2) IN IRAS F10214+4724

摘要

New observations with the IRAM interferometer of CO(3-2) from the highly luminous galaxy IRAS F10214+4724 show the source is 1.5″ x ≤0.9″; they display no evidence of any velocity gradient. This size, together with optical and IR data that show the galaxy is probably gravitationally lensed, lead to a new model for the CO distribution. In contrast to many lensed objects, we have a good estimate of the intrinsic CO and far-IR surface brightnesses, so we can derive the CO and far-IR/sub-mm magnifications. The CO is magnified 10 times and has a true radius of 400 pc, and the far-IR is magnified 13 times and has a radius of 250 pc. The true far-IR luminosity is 4-7 x 10~(12) solar luminosity, and the molecular gas mass is 2 x 10~(10) solar mass. This is nearly an order of magnitude less than previously estimated. Because the far-IR magnification is lower than the mid- and near-IR magnification, the intrinsic spectral energy distribution now peaks in the far-infrared. That is, nearly all the energy of this object is absorbed and reemitted in the far-infrared. In CO luminosity, molecular gas content, CO line width, and corrected far-IR luminosity, 10214+472 is a typical, warm, IR ultraluminous galaxy.