CO-CAVITY pilot survey: Molecular gas and star formation in void
  galaxies
  We present the first molecular gas mass survey of void galaxies. We compare
these new data together with data for the atomic gas mass and star formation
rate ($\rm SFR$) from the literature to those of galaxies in filaments and
walls in order to better understand how molecular gas and star formation are
related to the large-scale environment. We observed at the IRAM 30 m telescope
the CO(1-0) and CO(2-1) emission of 20 void galaxies selected from the Void
Galaxy Survey (VGS), with a stellar mass range from $\rm 10^{8.5}$ to $\rm
10^{10.3}M_{\odot}$. We detected 15 objects in at least one CO line. We
compared the molecular gas mass ($M_{\rm H_2}$), the star formation efficiency
($\rm SFE =SFR/M_{\rm H_2}$), the atomic gas mass, the molecular-to-atomic gas
mass ratio, and the specific star formation rate (sSFR) of the void galaxies
with two control samples of galaxies in filaments and walls, selected from
xCOLD GASS and EDGE-CALIFA, for different stellar mass bins and taking the star
formation activity into account. The results for the molecular gas mass for a
sample of 20 voids galaxies allowed us to make a statistical comparison to
galaxies in filaments and walls for the first time.
