HI in Elliptical Galaxies

Elliptical Galaxies

HI absorption in radio galaxies

Twenty-two powerful radio galaxies have been searched for HI absorption. We find the highest probability of detecting HI in absorption among narrow-line compact (or small) galaxies or galaxies with indication of richer interstellar medium (i.e. with ongoing or recent starformation). We discuss the difficulty in the interpretation of the origin of the HI absorption due to the uncertainty in the ...

HI in Early-type Galaxies

We summarise the HI properties of early-type galaxies, in particular the differences in HI morphologies observed in early-type galaxies of different luminosities. We find that in low-luminosity early-type galaxies the HI is almost always in a disk-like structure, with central surface densities high enough for star formation to occur. In a few luminous early-type galaxies the HI is also in a dis...

The HI content of elliptical and lenticular galaxies with recent star formation

As a first step toward constraining the efficiency of the star formation episodes that lead to elliptical (E) and lenticular (S0) K+A galaxies, a survey for HI within a sample of E and S0 K+A galaxies and their likely progenitors (i.e., actively star forming E and S0 galaxies) has been conducted with the NRAO Green Bank Telescope (GBT). The sample was taken from a larger parent sample drawn fro...

Modes of Elliptical Galaxies

Long lived modes of elliptical galaxies can existà la van Kampen. Specific systems may possess long lived oscillations which Landau damp on time scales longer than a Hubble time. Some physical processes such as a close encounter, tidal forces from a cluster or an orbiting satellite could preferentially excite a coherent mode. These may relate to the observed faint structure in elliptical galaxi...