Molecular Gas Superwind from the Face-On Wolf-Rayet Galaxy Markarian 1259

We report results of $^{12}$CO ($J=1$-0) mapping observations of theWolf-Rayet starburst galaxy Mrk 1259 which has optical evidence for thesuperwind seen from a nearly pole-on view. The CO emission is detected in thecentral 4 kpc region. The nuclear CO spectrum shows a blue-shifted ($\Delta V\simeq -27$ km s$^{-1}$) broad (FWHM $\simeq$ 114 km s$^{-1}$) component aswell as the narrow one (FWHM $\simeq 68$ km s$^{-1}$). The off-nuclear COspectra also show the single-peaked broad component (FWHM $\simeq$ 100 kms$^{-1}$). The single-peaked CO profiles of both the nuclear and off-nuclearregions may be explained if we introduce a CO gas disk with a velocitydispersion of $\sim 100$ km s$^{-1}$. If this gas disk would be extended up toa few kpc in radius, we may explain the wide line widths of the off-nuclear COemission. Alternatively, we may attribute the off-nuclear CO emission to thegas associated with the superwind. However, if all the CO gas moves along thebiconical surface of the superwind, the CO spectra would show double-peakedprofiles. Hence, the single-peaked CO profiles of the off-nuclear regions maybe explained by an idea that the morphology and/or velocity field of themolecular-gas superwind are more complex as suggested by hydrodynamicalsimulations.