TY  - GEN
KW  - secular evolution 
KW  -  spiral structure
ID  - heidok11132
N1  - id: DOI: 10.1111/j.1365-2966.2010.16931.x
Y1  - 2010///
TI  - Spiral Arms and their Effects on Secular Evolution and Star Formation in Disk Galaxies
AV  - public
N2  - We investigate how spiral structure affects the observational properties of disk galaxies both in terms of dynamical secular evolution and of star formation. We derived the first observational estimate of the torque-induced instantaneous angular momentum flow, resulting from non-axisymmetric features in the stellar distribution for a sample of 24 galaxies. The strongest torques were found among barred galaxies. In the inner regions, the average torques are strong enough to redistribute angular momentum on a timescale of ~4 Gyr with an outward angular momentum flow. In examining the role of spiral arms in star formation we found that they do not dominate, even in grand-design spiral galaxies as there is a comparable amount of interarm star formation. Further, we found that the arms show no enhancement in the efficiency of star formation in terms of molecular gas. We searched algorithmically for angular offsets between star formation tracers and found that there was no systematic spatial ordering of these tracers, as would be predictable by a shock triggering model of spiral structure. It seems spiral structure is most likely transient or at least more complex than the simplest models predict. These results point to a spiral structure that plays a lesser role in shaping a galaxy?s observable properties as was previously thought. The strength of gravitational torques depends more strongly on bars than on spiral structure, and spiral arms are not regions of enhanced star formation efficiency. At best they act to reorganize the interstellar medium and concentrate the gas.
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/11132/
A1  - Foyle, Kelly
ER  -