Detection of Molecular Gas in Void Galaxies : Implications for Star
  Formation in Isolated Environments
  We present the detection of molecular gas from galaxies located in nearby
voids using the CO line emission as a tracer. The observations were done using
the 45m Nobeyama Radio Telescope. Void galaxies lie in the most under dense
parts of our universe and a significant fraction of them are gas rich, late
type spiral galaxies. Although isolated, they have ongoing star formation but
appear to be slowly evolving compared to galaxies in denser environments. Not
much is known about their star formation properties or cold gas content. In
this study we searched for molecular gas in five void galaxies. The galaxies
were selected based on their relatively high IRAS fluxes or Ha line
luminosities, both of which signify ongoing star formation. All five galaxies
appear to be isolated and two lie within the Bootes void. We detected CO line
emission from four of the five galaxies in our sample and the molecular gas
masses lie between 10^8 to 10^9 Msolar. We did follow-up Ha imaging
observations of three detected galaxies using the Himalayan Chandra Telescope
and determined their star formation rates (SFRs). The SFR varies from 0.2 to 1
Msolar/yr, which is similar to that observed in local galaxies. Our study
indicates that although void galaxies reside in under dense regions, their
disks contain molecular gas and have star formation rates similar to galaxies
in denser environments.
