Detalles de publicación
PP 07008
Evolution of structure in late-type spiral galaxies: I. Ionized gas kinematics in NGC628
(1)Instituto de Astrofísca de Canarias (2)Consejo Superior de Investigaciones
Científicas (3) Dept. de Física Teórica y del Cosmos, U.Granada (4) Dept. Astronomía, U.Montreal
We study two-dimensional Fabry-Perot interferometric observations of the nearby face-on late-type spiral galaxy, NGC 628, in order to analyse the ionized gas
component of its insterstellar medium. Covering the galaxy out to a radius a little over 12 kpc, with a spatial sampling of 1.6 arcsec, we investigate the
large-scale dynamics as well as the feedback from individual HII regions into their surrounding medium. W study the role of gravitational perturbations along with that of external triggers which can disturb the kinematics and morphology of NGC628. We verify the presence of an inner rapidly rotating disc component, which we interpret as cause by slow secular evolution of the large scale structure: the spiral arms and oval distorsion of the disc. Combining our observations with auxiliary data we find evidence that gas is falling in from the outer parts of the galaxy towards the central regions, where a nuclear ring has formed at the radius of the Inner Lindblad Resonance of an m = perturbation,
which could help to build a pseudo-bulge in NGC 628. We go on to calculate radial profiles of the emission line velocity dispersion which we use to study the role of feedback from individual H II regions. The mean velocity dispersion for the ionized gas ( excluding pixels which belong to individual identifiable HII regions), does not vary greatly out to 12 kpc, though it does show a steady
decline, from 20 to 14 km/s in the outer parts. The current paper demonstrates a number of tools which we have developed for building a solid framework for studying the evolution of structure in spiral galaxies using two dimensional
kinematic observations.
component of its insterstellar medium. Covering the galaxy out to a radius a little over 12 kpc, with a spatial sampling of 1.6 arcsec, we investigate the
large-scale dynamics as well as the feedback from individual HII regions into their surrounding medium. W study the role of gravitational perturbations along with that of external triggers which can disturb the kinematics and morphology of NGC628. We verify the presence of an inner rapidly rotating disc component, which we interpret as cause by slow secular evolution of the large scale structure: the spiral arms and oval distorsion of the disc. Combining our observations with auxiliary data we find evidence that gas is falling in from the outer parts of the galaxy towards the central regions, where a nuclear ring has formed at the radius of the Inner Lindblad Resonance of an m = perturbation,
which could help to build a pseudo-bulge in NGC 628. We go on to calculate radial profiles of the emission line velocity dispersion which we use to study the role of feedback from individual H II regions. The mean velocity dispersion for the ionized gas ( excluding pixels which belong to individual identifiable HII regions), does not vary greatly out to 12 kpc, though it does show a steady
decline, from 20 to 14 km/s in the outer parts. The current paper demonstrates a number of tools which we have developed for building a solid framework for studying the evolution of structure in spiral galaxies using two dimensional
kinematic observations.