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Elliptical Galaxies.

The nearest and most prominent radio elliptical galaxy is NGC 5128 (Cen A). HI, OH, and H₂CO absorption features have been detected near the systemic velocity of the galaxy (550 kms^-1). The HI absorption line extends from about 500 to 700 kms^-1, whereas the HI emission is much broader, extending rather symmetrically over $\sim$500 kms^-1 (Gardner & Whiteoak 1976, and references therein). High-resolution VLA observations by van der Hulst, Golisch & Haschick (1983) show three rather narrow absorption features, one at the systemic velocity of CenA and the other two at +26 and +46 kms^-1. The red-shifted components possibly arise from clouds falling into the nucleus where they fuel the central engine; this has also been observed in several other radio elliptical galaxies (see van Gorkom et al. 1990).

Several narrow absorption features, both at the systemic velocity and at red-shifted velocities, have been observed against the nucleus of the early-type galaxy NGC 1052 (van Gorkom et al. 1986).

Other radio elliptical galaxies detected in HI absorption are NGC 315, NGC 1275, NGC 3894, NGC 5363, 3C236, and 4C31.06, bringing the number of detections up to eight (van Gorkom et al. 1989, and references therein).