We present an analysis of the H2 emission-line gas kinematics in the inner < 4 arcsec radius of six nearby spiral galaxies, based on AO-assisted integral-field observations obtained in the K-band with SINFONI/VLT. Four of the six galaxies in our samp
le display ordered H2 velocity fields, consistent with gas moving in the plane of the galaxy and rotating in the same direction as the stars. However, the gas kinematics is typically far from simple circular motion. We can classify the observed velocity fields into four different types of flows, ordered by increasing complexity: (1) circular motion in a disc (NGC3351); (2) oval motion in the galaxy plane (NGC3627 and NGC4536); (3) streaming motion superimposed on circular rotation (NGC4501); and (4) disordered streaming motions (NGC4569 and NGC4579). The H2 velocity dispersion in the galaxies is usually higher than 50 km/s in the inner 1-2 arcsec radii. The four galaxies with ordered kinematics have v/sigma < 1 at radii less than 40-80 pc. The radius at which v/sigma = 1 is independent of the type of nuclear activity. While the low values of v/sigma could be taken as an indication of a thick disc in the innermost regions of the galaxies, other lines of evidence (e.g. H2 morphologies and velocity fields) argue for a thin disc interpretation in the case of NGC3351 and NGC4536. We discuss the implications of the high values of velocity dispersion for the dynamics of the gaseous disc and suggest caution when interpreting the velocity dispersion of ionized and warm tracers as being entirely dynamical. Understanding the nature and role of the velocity dispersion in the gas dynamics, together with the full 2D information of the gas, is essential for obtaining accurate black hole masses from gas kinematics.
We aim to define a sample of intermediate-z disk galaxies harbouring central bulges, and a complementary sample of disk galaxies without measurable bulges. We intend to provide colour profiles for both samples, as well as measurements of nuclear, dis
k, and global colours, which may be used to constrain the relative ages of bulges and disks. We select a diameter-limited sample of galaxies in images from the HST/WFPC2 Groth Strip survey, which is divided into two subsamples of higher and lower inclination to assess the role of dust in the measures quantities. Mergers are visually identified and excluded. We take special care to control the pollution by ellipticals. The bulge sample is defined with a criterion based on nuclear surface brightness excess over the inward extrapolation of the exponential law fitted to the outer regions of the galaxies. We extract colour profiles on the semi-minor axis least affected by dust in the disk, and measure nuclear colours at 0.85 kpc from the centre over those profiles. Disk colours are measured on major axis profiles; global colours are obtained from 2.6-diameter apertures. We obtain a parent sample containing 248 galaxies with known redshifts, spectroscopic or photometric, spanning 0.1 < z < 1.2. The bulge subsample comprises 54 galaxies (21.8% of the total), while the subsample with no measureable bulges is 55.2% of the total (137 galaxies). The remainder (23%) is composed of mergers. We list nuclear, disk, and global colours (observed and restframe) and magnitudes (apparent and absolute), as well as galaxy colour gradients for the samples with and without bulges. We also provide images, colour maps, plots of spectral energy distributions, major-axis surface brightness profiles, and minor-axis colour profiles for both samples.
