Fig. 1. ¹²CO (1-0) spectra for three positions in the dIrr galaxy Leo A. Positions 1 and 3 coincide with maxima in the H I column density, where atomic gas with low velocity dispersion was detected. Position 2 corresponds to the galaxy center, where there is a hole in the H I distribution. The upper spectrum for each position has a velocity resolution of 2.6 km s^-1 (1 MHz); the lower spectrum has been smoothed to 5.2 km s^-1 (2 MHz)

Fig. 2. A plot of log (L(CO)/M(H I)) versus oxygen abundance for all the dwarf galaxies in the literature which have CO, H I and oxygen abundance data available. A trend for low metallicity galaxies to have only upper limits is shown, with no dwarfs at metallicities less than 12 + log O/H = 7.9 detected in CO