Outflows in active galactic nucleus/starburst-composite ultraluminous infrared galaxies

Galactic superwinds occur in almost all infrared-luminous galaxies with star formation rates (SFRs) above 10 M-circle dot yr(-1), as shown by studies of the Na I D interstellar absorption line. We demonstrate that this result also applies to ultraluminous infrared galaxies (ULIRGs) that host an active galactic nucleus (AGN) embedded in a strong starburst (SFR >= 100 M-circle dot yr(-1)) by studying a sample of 26 Seyfert ULIRGs in Na I D. The infrared luminosity of these galaxies is powered jointly by the AGN and starburst. We find that there are hints of the influence of the AGN on outflows in Seyfert 2/starburst composites, but the evidence is not yet statistically conclusive. The evidence we find is lower wind detection rates (i.e., wind opening angles) in Seyfert 2 ULIRGs than in galaxies of comparable L-IR, higher velocities than in galaxies of comparable SFR, and correlations between the neutral gas and the ionized gas in the extended narrow-line region. Although the AGN probably contributes to the outflows in Seyfert 2 ULIRGs, its momentum and energy injection is equal to or less than that of the starburst. Similarly, the outflow mechanical luminosity ( energy outflow rate) per unit radiative luminosity is the same for starburst and Seyfert 2 ULIRGs. In the nuclei of Seyfert 1 ULIRGs, we observe small-scale outflows that are powered solely by the AGN. However, in Mrk 231, we observe both a high-velocity, small-scale and low-velocity, extended outflow. The latter may be powered by a starburst or radio jet. These large-scale, lower velocity outflows certainly exist in other Seyfert 1 ULIRGs, but they are washed out by the light of the nucleus.