Large Scale Complexes in Spiral Galaxies in the Spitzer Survey of Stellar Structure in Galaxies (S4G)
Abstract
Properties of nearly 3000 star-forming complexes in a sample of 45 local spiral galaxies across a range of Hubble types and arm classes have been studied using infrared data from the Spitzer Space Telescope and optical data from the Sloan Digital Sky Survey. The luminosities of the brightest complexes scale with galaxy luminosity. Luminosity functions yield power law slopes, although complexes in “beads on a string” structures are skewed towards higher mass. Many infrared beads are in dust lanes rather than optical spiral arms. The physical separations of the beaded complexes scale with their masses; the separations scaled to the galaxy size increase as the complex luminosity/galaxy luminosity ratio increases. These results are consistent with formation by a large-scale gravitational instability. The most massive complexes range from 10^5 to 10^7 Mo. In contrast, high redshift galaxies in the Ultra Deep Field have complex masses 100 times greater for a given galaxy luminosity.
- Publication:
-
American Astronomical Society Meeting Abstracts #221
- Pub Date:
- January 2013
- Bibcode:
- 2013AAS...22114604E