21.02.2013 Views

Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

It is easy to see that the non-rotators with face on disks would have to be <strong>in</strong>tr<strong>in</strong>si-<br />

cally rotat<strong>in</strong>g very fast for their rotation to register over the r<strong>and</strong>om motions <strong>in</strong> these<br />

cases. From the observations of systems at greater <strong>in</strong>cl<strong>in</strong>ations we have no cause to<br />

expect any disks to be rotat<strong>in</strong>g that fast. In a similar manner we plot the values of<br />

σ100pc aga<strong>in</strong>st dust disk axis ratio, or dust lane width to length ratio <strong>in</strong> Figure 3.25.<br />

Here we see no clear trend <strong>in</strong> velocity dispersion with axis ratio.<br />

We f<strong>in</strong>d no significant systematic differences between the typical values σ100pc be-<br />

tween the two classes. Us<strong>in</strong>g the Kolmogorov-Smirnov Test to assess the two groups<br />

we f<strong>in</strong>d a probability of 0.93 that the distributions of velocity dispersions were drawn<br />

from the same underly<strong>in</strong>g distribution. Apply<strong>in</strong>g the same test to the ∆100pc param-<br />

eter gives only a 0.08 probability that these were drawn from the same distribution.<br />

This evidence suggests to us that rotators <strong>and</strong> non-rotators represent the same<br />

type of k<strong>in</strong>ematic systems, with observational effects such as <strong>in</strong>cl<strong>in</strong>ation <strong>and</strong> dust<br />

properties limit<strong>in</strong>g our ability to detect the rotation of those systems where we do<br />

not. We conclude that a model of a rotat<strong>in</strong>g gas disk with significant r<strong>and</strong>om motions<br />

is compatible with all of the observations.<br />

82

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!