Some Fabry-Perot Images of Spiral Galaxies

• The first series of images refers to NGC 1672, a barred spiral. We present a gray scale V-band image to show the overall morphology, followed by an intensity map in H-alpha which shows how the H II regions are distributed, followed by the velocity map.

• Gray Scale V-band Image of NGC 1672:

  

• H-alpha Intensity Image of NGC 1672. Note how the most intense regions of H-alpha emission are near the ends of the bar (and in the nucleus).

  

• Velocity Field of NGC 1672. Different colors refer to different velocities as the galaxy is rotating. Note that the core also shows strong rotation.

  

• The following image is an H-alpha intensity map of the spiral galaxy NGC 1292. The Bright Red spots are prominent H II regions and the blue represents more diffuse emission. Virtually every place in the disk of this galaxy emits H-alpha radiation.

  

• This next image is an H-alpha intensity map of the spiral galaxy NGC 1406. Again, several prominent H II regions can be seen near the center, while more diffuse emission is seen in the outer regions.

• This next image is the two dimensional velocity field, obtained in the manner described above. The picture is coded so that blue represents the part of the galaxy that is coming toward us, as the disk rotates around a central point, and the red represents that part of the disk which is rotating away from us. The total rotation amplitude is about 150 km/s. Noticed the detached red area, that represents a still higher velocity H-alpha complex which may represent tidal debris or a small, companion galaxy.

  

• The graph represents points along a vector that goes from the center of the galaxy out to the red edge. At each point along this vector, a velocity is determined and hence this represents a crude rotation curve. Notice that the rotation rises steeply near the center, and then flattens out at large radii. This behavior is typical for most spiral galaxies.

More Data:

• Slides of Interacting Galaxies