The Cold Gas Content of Elliptical Galaxies
The 100m radiotelescope at Effelsberg has been used to observe two samples of elliptical galaxies in the 21cm line of neutral hydrogen. One sample is defined by the elliptical galaxies in the Revised-Shapely-Ames catalog (RSA) (Huchtmeier 1994, Astron.Astrophys286, p.389); the other sample is defined by all elliptical galaxies with IRAS 100 μ fluxes ≥ 500mJy north of declination -31° (Huchtmeier, Sage, Henkel 1995 Astron.Astrophys. in press). Among the detected galaxies there are 23 (RSA) and 24 (IRAS) isolated elliptical galaxies free of confusion by nearby galaxies with similar radial velocities. Global properties of these two samples of elliptical galaxies are discussed: their HI-properties, optical and IR luminosities, their optical colors, their masses of dust and of molecular hydrogen.