CO J = 2-1 LINE EMISSION IN CLUSTER GALAXIES AT z ∼ 1: FUELING STAR FORMATION IN DENSE ENVIRONMENTS

We present observations of CO J = 2-1 line emission in infrared-luminous cluster galaxies at z ~ 1 using the IRAM Plateau de Bure Interferometer. We calculate 3[sigma] upper limits to the CO J = 2-1 line luminosities, L super(1) sub(CO) < 6.08 x 10 super(9) and < 6.63 x 10 super(9) K km s super(-1) pc super(2). The optical spectrum of this object suggests that it is likely an obscured AGN, and the measured CO line luminosity is L' sub(CO) = (1.94 + or - 0.35) x 10 super(10) K km s-1 pc super(2), which leads to an estimated cold molecular gas mass M sub(H) sub(2) = (1.55 + or - 0.28) x 10 super(10) M sub([middot in circle]). A significant reservoir of molecular gas in a z ~ 1 galaxy located away from the cluster center demonstrates that the fuel can exist to drive an increase in star formation and AGN activity at the outskirts of high-redshift clusters.