Gemini NIFS survey of feeding and feedback in nearby active galaxies – III. Ionized versus warm molecular gas masses and distributions

Abstract

We have used the Gemini Near-Infrared Integral Field Spectrograph (NIFS) in\nthe J and K bands to map the distribution, excitation and kinematics of the\nionized HII and warm molecular gas H$_2$, in the inner few 100 pc of 6 nearby\nactive galaxies: NGC 788, Mrk 607, NGC 3227, NGC 3516, NGC 5506, NGC 5899. {For\nmost galaxies, this is the first time that such maps have been obtained}. The\nionized and H$_2$ gas show distinct kinematics: while the H$_2$ gas is mostly\nrotating in the galaxy plane with low velocity dispersion ($\\sigma$), the\nionized gas usually shows signatures of outflows associated with higher\n$\\sigma$ values, most clearly seen in the [FeII] emission line. These two gas\nspecies also present distinct flux distributions: the H$_2$ is more uniformly\nspread over the whole galaxy plane, while the ionized gas is more concentrated\naround the nucleus and/or collimated along the ionization axis of its Active\nGalactic Nucleus (AGN), presenting a steeper gradient in the average surface\nmass density profile than the H$_2$ gas. The total HII masses cover the range\n$2\\times10^5-2\\times10^7$ M$_{\\odot}$, with surface mass densities in the range\n3-150 M$_{\\odot}$ pc$^{-2}$, while for the warm H$_2$ the values are 10$^{3-4}$\ntimes lower. We estimate that the available gas reservoir is at least $\\approx$\n100 times more massive than needed to power the AGN. If this gas form new stars\nthe star-formation rates, obtained from the Kennicutt-schmidt scalling\nrelation, are in the range 1-260$\\times$ 10$^{-3}$ M$_{\\odot}$ yr$^{-1}$. But\nthe gas will also - at least in part - be ejected in the form of the observed\notflows.\n