| |
 |
| Paper: |
Amplitudes of Spiral Perturbations |
| Volume: |
480, Structure and Dynamics of Disk Galaxies |
| Page: |
117 |
| Authors: |
Grosbol, P.; Patsis, P. A. |
| Abstract: |
It has proven very difficult to estimate the amplitudes of spiral
perturbations in disk galaxies from observations due to the variation of
mass-to-light ratio and extinction across spiral arms. Deep, near-infrared
images of grand-design spiral galaxies obtained with HAWK-I/VLT were used to
analyze the azimuthal amplitude and shape of arms, which, even in the K-band
may,
be significantly biased by the presence of young stellar populations. Several
techniques were applied to evaluate the relative importance of young stars
across the arms, such as surface brightness of the disk with light from
clusters subtracted, number density of clusters detected, and texture of the
disk. The modulation of the texture measurement,
which correlates with the number
density of faint clusters, yields amplitudes of the spiral perturbation in the
range 0.1–0.2. This estimate gives a better estimate of the mass perturbation
in the spiral arms, since it is dominated by old clusters. |
|
|
|
|
|
