ar X iv : a st ro - p h / 98 03 16 9 v 1 1 5 M ar 1 99 8 MOLECULAR - GAS SUPERWIND FROM THE FACE - ON WOLF - RAYET GALAXY MRK 1259

We report results of CO (J = 1-0) mapping observations of the Wolf-Rayet starburst galaxy Mrk 1259 which has optical evidence for the superwind seen from a nearly pole-on view. The CO emission is detected in the central 4 kpc region. The nuclear CO spectrum shows a blue-shifted (∆V ≃ −27 km s) broad (FWHM ≃ 114 km s) component as well as the narrow one (FWHM ≃ 68 km s). The off-nuclear CO spectra also show the single-peaked broad component (FWHM ≃ 100 km s). The single-peaked CO profiles of both the nuclear and off-nuclear regions may be explained if we introduce a CO gas disk with a velocity dispersion of ∼ 100 km s. If this gas disk would be extended up to a few kpc in radius, we may explain the wide line widths of the off-nuclear CO emission. Alternatively, we may attribute the off-nuclear CO emission to the gas associated with the superwind. However, if all the CO gas moves along the biconical surface of the superwind, the CO spectra would show double-peaked profiles. Hence, the single-peaked CO profiles of the off-nuclear regions may be explained by an idea that the morphology and/or velocity field of the molecular-gas superwind are more complex as suggested by hydrodynamical simulations. Subject headings: galaxies: individual (Mrk 1259) galaxies: starburst ISM: molecules