The Planetary Nebula Luminosity Function: Pieces of the Puzzle

TL;DR

This paper reviews the planetary nebula luminosity function (PNLF), discussing its physical basis, features of the H-alpha PNLF, and recent findings on the number of PNe relative to stellar populations across different galaxy types.

Contribution

It provides a comprehensive review of the current understanding of the PNLF, including new insights into the alpha parameter across galaxy types and the physical processes shaping the PNLF.

Findings

The alpha parameter is similar in star-forming spirals and elliptical galaxies.

The H-alpha PNLF has features distinct from the [O III] PNLF.

Physical processes influencing the PNLF structure are discussed.

Abstract

Extragalactic surveys in the emission line of [O III] 5007 have provided us with the absolute line strengths of large, homogeneous sets of planetary nebulae. These data have been used to address a host of problems, from the measurement of the extragalactic distance scale, to the study of stellar populations. I review our current understanding of the [O III] planetary nebula luminosity function (PNLF), and discuss some of the physical processes that effect its structure. I also describe the features of the H-alpha PNLF, a function that, upon first glance, looks similar to the [O III] PNLF, but which includes a very different set of objects. Finally, I discuss recent measurements of alpha, the number of PNe found in a stellar population, normalized to that population's bolometric luminosity. I show that, contrary to expectations, the values of alpha found in actively star-forming spirals is essentially the same as those measured in late-type elliptical and lenticular systems. I discuss how this result sheds light on the physics of the planetary nebula phenomenon.