16891

Massive galaxies at high-z are known to co-evolve with their circumgalactic medium (CGM) comma generally detected in Ly-alpha. The most extreme environments are Enormous Ly-alpha Nebulae (ELANe) comma found in the cores of proto- clusters. We propose to use the VLA to observe CO(1-0) in two spectacular ELANe from an ALMA survey at zvirgul2. Q1416+2649 shows gas across 100 kpc with an extremely broad FWHM(virgul1000km-s) comma while Q2123-0050 shows companions with widely varying CO-CI line ratios and cold gas in the CGM. The CO(1-0) observations will give the most reliable estimates of the mass of the cold gas and trace the most extended molecular reservoirs. Together with the CO(4-3) comma CORCHETE_OPENCICORCHETE_CLOSE comma and Lya comma the crucial CO(1-0) data will allows us to probe the physical conditions of the multi- phase gas in the various regions of these nebulae. We will compare this to similar studies done on the enigmatic Spiderweb and MAMMOTH-I nebulae. This will start to give us a handle on the statistical properties of the various molecular tracers in ELANe comma and allow us to study massive galaxies.