Planetary Nebulae as Tracers of the Intergalactic Stellar Background: a Population Synthesis Theoretical Approach

Abstract

We wish to assess the relationship between the population of planetary nebulae (PNe) and a given parent stellar population from a theoretical point of view. Our results rely on original population synthesis models used to estimate the expected luminosity-specific PN density accounting for different evolutionary scenarios and star formation histories, as observed in galaxies in the near Universe. For a complete PN sample, we find that 1 PN/1.5E06 L(sun) a safe (IMF-independent) lower limit to the traced global bolometric luminosity of the parent stellar population. A tentative application to Virgo cluster data allows us to place a lower limit at ~7% for the global B luminosity of the cluster provided by "loose" intergalactic stars.