Key Results on the Ionized Gas Halo of NGC 5775
Abstract
We present key results from deep spectra of the diffuse ionized gas (DIG) halo of the edge-on galaxy NGC 5775. Emission has been detected up to z≈ 13 kpc above the plane in one of two vertically oriented long slits, making this the spiral galaxy with the greatest spectroscopically detected halo extent in emission. Diagnostic line ratios, measurable up to z≈ 8 kpc, indicate clear departures from pure, dilute photo-ionization scenarios. Velocities of the gas in both slits approach the systemic velocity of the galaxy at several kpc above the plane. We interpret this trend as a decrease in rotation velocity with z, with essentially no rotation at heights of several kpc. This falloff is presumably due to the gravitational potential changing with z, but will also depend on the hydrodynamic nature of the disk-halo cycling of gas and projection effects.
- Publication:
-
Gas and Galaxy Evolution
- Pub Date:
- 2001
- Bibcode:
- 2001ASPC..240..394R