Planetary Nebulae as tracers of the diffuse IG stellar background: a
population synthesis theoretical approach
A. Buzzoni1, M. Arnaboldi2
1INAF, Oss. Astronomico di Bologna, Italy
2INAF, Obs. of Turin, Pino Torinese, Italy
The problem of a proper assessment of
the stellar contribution to the
diffuse intergalactic background is discussed from the theoretical
point of view. This is done relying on original population synthesis
models to estimate the expected Planetary Nebula (PN) event rate per
unit luminosity of the parent stellar population. Our models account
for different evolutionary scenarios and star formation histories as
observed in the local galaxy sample (from E to Im morphological types).
In a complete PN sample we find that 1 PN/106 L_sun is a
safe (IMF-independent) lower limit to the traced global bolometric
luminosity of the parent stellar population. The apparent relative lack
of PNe in elliptical galaxies is also briefly reviewed in our
contribution, leading to a possible new interpretative scenario in the
framework of the most recent advances of stellar astrophysics in the
post-horizontal branch evolution.