Extraplanar Emission-Line Gas in NGC 891
Abstract
We have used spectroscopy and high-resolution imaging to study the disk-halo interaction in the edge-on spiral galaxy NGC 891, which is known to have extraplanar gas. Hα imaging of the northeast side of this galaxy reveals diffuse emission-line gas both above and below the plane, as well as new bubble-like structures on 0.5-1 kpc scales emerging from the disk. The diffuse emission is best modeled in the radial direction as a disk of constant emission measure with a sharp cutoff. Long-slit spectroscopy of the Hα line within 2.4 kpc of the galaxy's plane shows departures from the velocity structure found in a model with strict corotation. The departures from corotation range up to 40 km s^-1^, consistent with galactic fountain theory.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1994
- DOI:
- 10.1086/173798
- Bibcode:
- 1994ApJ...423..190P
- Keywords:
-
- Astronomical Models;
- Corotation;
- Emission Spectra;
- H Alpha Line;
- Spiral Galaxies;
- Bubbles;
- Gas Ionization;
- Halos;
- Interstellar Matter;
- Kinematics;
- Prominences;
- Astrophysics;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 891;
- GALAXIES: ISM;
- GALAXIES: KINEMATICS AND DYNAMICS;
- GALAXIES: SPIRAL