Detalles de publicación
PP 015040
Comparative internal kinematics of the HII regions in interacting and isolated galaxies: implications for massive star formation modes
1. Instituto de Astrofísica de Canarias 2. Dept. Astrofísica, U. La Laguna
3. CSIC, 4. Observatorio de Estocolmo, Dto. Astronomía U. Estocolmo, 5. Instituto de Investigación en Astrofísica, U. Liverpool John Moores-
We have observed 10 interacting galaxy pairs using the Fabry-Perot interferometerGH aFaS (Galaxy H Fabry-Perot system) on the 4.2m William Herschel Telescope(WHT) at the Observatorio del Roque de los Muchachos, La Palma. We present here the H alpha surface brightness, velocity and velocity dispersion maps for the 10 systems we have not previously observed using this technique, as well as the physical properties(sizes, H alpha luminosities and velocity
dispersion) of 1259 Hii regions from the full sample. We also derive the physical properties of 1054 Hii regions in a sample of 28 isolated galaxies observed with the same instrument in order to compare the two populations of HII regions. We find a population of the brightest HII regions for
which the scaling relations, for example the relation between the H alpha luminosity and the radius, are clearly distinct from the relations for the regions of lower luminosity. The regions in this bright population are more frequent in the interacting galaxies. We find that the turbulence, and also the star formation rate, are enhanced in the HII regions in the interacting galaxies. We have also extracted the H equivalent widths for the HII regions of both samples, and we have found that the distribution of HII region ages coincides for the two samples of galaxies. We suggest that the SFR enhancement
is brought about by gas flows induced by the interactions, which give rise
to gravitationally bound gas clouds which grow further by accretion from the flowing gas, producing conditions favourable to star formation.
dispersion) of 1259 Hii regions from the full sample. We also derive the physical properties of 1054 Hii regions in a sample of 28 isolated galaxies observed with the same instrument in order to compare the two populations of HII regions. We find a population of the brightest HII regions for
which the scaling relations, for example the relation between the H alpha luminosity and the radius, are clearly distinct from the relations for the regions of lower luminosity. The regions in this bright population are more frequent in the interacting galaxies. We find that the turbulence, and also the star formation rate, are enhanced in the HII regions in the interacting galaxies. We have also extracted the H equivalent widths for the HII regions of both samples, and we have found that the distribution of HII region ages coincides for the two samples of galaxies. We suggest that the SFR enhancement
is brought about by gas flows induced by the interactions, which give rise
to gravitationally bound gas clouds which grow further by accretion from the flowing gas, producing conditions favourable to star formation.