Detection of CO(1-0) emission and optical imaging of the Seyfert galaxy/QSO Markarian 231

The detection of CO(J = 1-0) emission and optical imaging of the luminous infrared galaxy Markarian 231 are reported. The galaxy is extremely rich in molecular gas with MT(H2) approximately equal to 1.4 x 10 to the 10th solar masses, approximately 5 times the molecular gas content of the Galaxy. Markarian 231 is the most luminous object in the local universe (z approximately equal to or less than 0.1), with a far-infrared luminosity (lambda = 40-400 microns) of 2.1 x 10 to the 12th solar luminosities. THe CO detection yields a L(FIR)/M(H2) ratio of 150. A deep optical CCD image shows two striking tidal tails with total extent of about 75 kpc. The CCD image strongly suggests that Markarian 231 is an advanced merger system. If the molecular gas is highly concentrated in the nuclear region it may fuel an intense starburst and possibly feed the accretion onto an embedded QSO. The trigger for the intense activity observed in Markarian 231 appears to be the collision of two gas-rich spiral galaxies.