Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

Gas Radial Velocity (km s -1 )
Gas Radial Velocity (km s -1 )
Gas Radial Velocity (km s -1 )
200
100
0
-100
-200
-300
200
100
0
-100
-200
-300
200
100
0
-100
-200
-300
NGC193 Central Slit: ∆v = 47 km s -1
-1.0 -0.5 0.0 0.5 1.0
Position along slit (arcsec)
-ve offset slit position
-1.0 -0.5 0.0 0.5 1.0
Position along slit (arcsec)
+ve offset slit position
-1.0 -0.5 0.0 0.5 1.0
Position along slit (arcsec)
Gas Radial Velocity (km s -1 )
Gas Radial Velocity (km s -1 )
200
100
0
-100
-200
-300
200
100
0
-100
-200
-300
NGC193 Central Slit: ∆v = 90 km s -1
-1.0 -0.5 0.0 0.5 1.0
Position along slit (arcsec)
-ve offset slit position
-1.0 -0.5 0.0 0.5 1.0
Position along slit (arcsec)
+ve offset slit position
-1.0 -0.5 0.0 0.5 1.0
Position along slit (arcsec)
Figure 4.23 The observed velocity profiles of NGC 193 for each of the three observed
slit positions: (left) offset by the velocity and slope calculated in §4.2.5 and (right)
with a velocity offset of 90 km s −1 , and the velocity field running from positive to
negative, which provides a more meaningful fit (judged by the author). The velocities
are shown shaded according to the relative signal-to-noise of each spectrum, formal
errors from the fit are also indicated (see Chapter 3). The three solid lines show
model velocity profiles for no black hole, a 1 × 10 8 M⊙ black hole and a 9 × 10 8 M⊙
(the steeper lines from models with the greatest black hole mass). See text for details
of the models. The dashed vertical lines give a rough approximation of the sphere of
influence of a black hole based on the mass estimate from the M• − σ relation and
the size of the random motions observed.
Gas Radial Velocity (km s -1 )
200
100
0
-100
-200
-300
210