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Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

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as an alternative fit by eye provides a more satisfactory description of the very central<br />

k<strong>in</strong>ematics. In the observed velocity profile a central velocity gradient is observed<br />

which seems as if it may correspond to gas rotat<strong>in</strong>g <strong>in</strong> the potential generated by<br />

a 1 × 10 8 M⊙ < M• < 9 × 10 8 M⊙ black hole. Further from the nucleus the gas<br />

appears to have a flat velocity profile, possibly <strong>in</strong>dicat<strong>in</strong>g that the rotation of this gas<br />

is not along this axis. Two dimensional mapp<strong>in</strong>g of the velocity field would make it<br />

possible to determ<strong>in</strong>e if this gas was <strong>in</strong> a k<strong>in</strong>ematic system related to the secondary<br />

dust component. There is a possible sign of a jet-disk <strong>in</strong>teraction <strong>in</strong> the velocity field<br />

of this galaxy which is described <strong>in</strong> §4.43 below.<br />

NGC 315: This elliptical galaxy has a nuclear dust disk. The STIS slits were<br />

aligned parallel to the galaxy major axis, which is almost co<strong>in</strong>cident with the dust<br />

disk axis. The weighted mean observation - model residuals are plotted <strong>in</strong> Figure 4.2<br />

<strong>and</strong> gives a m<strong>in</strong>imum at an offset of −137 km s −1 , equivalent to a galaxy recessional<br />

velocity of 4956 km s −1 . The model velocity profiles for these observations are shown<br />

<strong>in</strong> Figure 4.24. It is not clear that the modeled velocity profiles match any of the<br />

observed k<strong>in</strong>ematics <strong>in</strong> the nuclear region.<br />

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