CO in the ALMA Radio-source Catalogue (ARC)

These galaxies plausibly have "normal" or even starbursty hosts. Overall, reservoirs of 10^7^<~MH_2_<~10^10^M_{sun}_ are seen at z<0.3, and 10^10^<~MH_2_<~10^12^M_{sun}_ at z>1. Taking into account the completeness correction of the sample, we created the corresponding H_2_ mass functions at 0.005<z<0.3 and 1<z<2.5.

The local mass function reveals that the number density of low-z RGs with detectable molecular gas reservoirs is only a little lower (a factor of ~4) than that of pure (or little star-forming) type 1 and 2 AGN in simulations. At 1<z<2.5, there is a significant decrease in the number density of high-z RGs due to the rarity of bright radio galaxies. An estimate for the missing faint RGs would, nonetheless, bring populations close again.

Finally, we find that the volume density of molecular gas locked up in the brightest 1/5000-1/7000 RGs is similar in the examined z bins. This result likely indicates that the inflow rate on one hand and the star-formation depletion rate plus the jet-driven expulsion rate on the other hand counteract each other in the most luminous RGs of each epoch.