Provided that 
0.1, the mass flux can readily
be provided by
general infall of gas from the body of the surrounding galaxy:
ordinary stellar mass loss processes yield ~ 10-11
M
yr-1 per solar
mass at the present epoch (and more in a young galaxy); and this
material would accumulate in the center, unless it were expelled by a
supernova-driven or intergalactic wind. Recent evidence for large
amounts of gas in some elliptical galaxies (e.g.,
NGC 4278) suggest that
this possibility is not restricted to spirals
[14,
15].