CHILES XII: The H  <scp>i</scp> evolution of Luminous Compact Blue Galaxies between 0 &amp;lt; <i>z</i> &amp;lt; 0.48

ABSTRACT We study the evolution of Luminous Compact Blue Galaxies (LCBGs) by making use of H i emission line data provided by the full 856 h COSMOS H i Large Extragalactic Survey (CHILES), which spans a redshift range of $0\le z \le 0.48$ within the COSMOS field. We report the results on a cubelet stacking analysis, which we use to estimate the average H i mass evolution of LCBGs in the field up to $z=0.48$. For the stacks that do not show a detection, we report an upper limit estimate of the average H i mass. We also report on two directly detected LCBGs. We find the average H i mass in LCBGs at redshifts $z=0.26$, $z=0.35$, and $z=0.45$ respectively to be $\langle M_{\rm H\,{{\small I}}}\rangle \lt 4.89\times 10^9$ M$_\odot$, $\langle M_{\rm H\,{{\small I}}}\rangle =(2.49\pm 0.75)\times 10^9$ M$_\odot$, and $\langle M_{\rm H\,{{\small I}}}\rangle =(6.44\pm 2.71)\times 10^9$ M$_\odot$. We see no strong evidence for evolution in the average H i mass over this redshift range, consistent with other recent studies of the evolution of the H i in galaxies at $z\lt 0.5$. On average, LCBGs appear to retain substantial gas reservoirs, with gas fractions staying constant and remaining broadly consistent with those of the larger star-forming population. LCBG gas depletion time-scales are nearly an order of magnitude shorter than in normal star-forming galaxies across the studied redshift range, aligning with the period during which their number density drops sharply.