Uncovering Planetary Nebulae in Early Type Galaxies using the Rutgers Fabry-Perot

Abstract

We report on observations of four early-type galaxies performed with the Rutgers Fabry-Perot in order to search for Planetary Nebulae (PNe) in these systems. The aim is to use the PNe as kinematic tracers of the galaxy potential. We describe our data reduction and analysis procedure and show that the proper calibration of our detection statistic is crucial in getting down to our limiting magnitude of $m_{5007} = 26.1$. In the case of the two Leo galaxies we find moderately sized samples: 54 PNe in NGC 3379 and 50 PNe in NGC 3384; NGC 4636 (2 PNe) and NGC 1549 (6 PNe) are included for completeness. We present our samples in tabular form, as well as the spectrum for each PN. We constructed simple non-parametric spherical mass models for NGC 3379 using a Monte Carlo Markov Chain method to explore the space of likely mass models. We find a remarkably constant mass-to-light ratio within five half-light radii with an overall $B$ band mass-to-light ratio $\sim 5$. A simple mass-to-light estimate for NGC 3384 yields $Υ_B \sim 11$, but is likely an overestimate.