The cold interstellar medium in elliptical galaxies - Observations ofHI and radio continuum emission.
Abstract
About 10% of nearby elliptical galaxies contain H I, with typical values of M(H I) ≡ 5×108M_sun; and M(H I)/LB ≡ 0.03 M_sun;/L_sun;. The H I content is unrelated to the stellar content, suggesting that the H I in early-type galaxies has an external origin and is not produced by mass loss. The H I and stellar kinematics show that the rotation curves of E and S0 galaxies are approximately flat. Large mass-to-light ratios are found for some systems. Comparison with mass models derived from X-ray emission suggests that these may in some cases overestimate the mass. The presence of H I is shown to enhance the likelihood that an E/S0 galaxy has a nuclear radio continuum source, in agreement with models which suggest that the central engine is fuelled by cold gas. Current data suggest that the gas-to-dust ratio for the cold interstellar medium in ellipticals has a value similar to that found in the solar neighborhood.
- Publication:
-
Structure and Dynamics of Elliptical Galaxies
- Pub Date:
- 1987
- DOI:
- 10.1007/978-94-009-3971-4_12
- Bibcode:
- 1987IAUS..127..145K
- Keywords:
-
- Elliptical Galaxies;
- H I Regions;
- Interstellar Matter;
- Radio Emission;
- Continuous Radiation;
- Cosmic Dust;
- Galactic Mass;
- Kinematics;
- Mass Distribution;
- Mass To Light Ratios;
- Astrophysics