We report the results of a photometric and spectroscopic survey for planetary nebulae ( PNe ) over the entire body of the Local Group spiral galaxy M33 .
We use our sample of 152 PNe to show that the bright end of the galaxy ’ s [ O III ] \lambda 5007 planetary nebula luminosity function ( PNLF ) has the same sharp cutoff seen in other galaxies .
The apparent magnitude of this cutoff , along with the DIRBE/IRAS foreground extinction estimate of E ( B - V ) = 0.041 , implies a distance modulus for the galaxy of ( m - M ) _ { 0 } = 24.86 ^ { +0.07 } _ { -0.11 } ( 0.94 ^ { +0.03 } _ { -0.05 } Mpc ) .
Although this value is \sim 15 \% larger than the galaxy ’ s Cepheid distance , the discrepancy likely arises from differing assumptions about the system ’ s internal extinction .
Our photometry , which extends more than 3 mag down the PNLF , also reveals that the faint-end of M33 ’ s PN luminosity function is non-monotonic , with an inflection point \sim 2 mag below the PNLF ’ s bright limit .
We argue that this feature is due to the galaxy ’ s large population of high core-mass planetaries , and that its amplitude may eventually be a useful diagnostic for studies of stellar populations .

Fiber-coupled spectroscopy of 140 of the PN candidates confirms that M33 ’ s PN population rotates along with the old disk , with a small asymmetric drift of \sim 10 km s ^ { -1 } .
Remarkably , the population ’ s line-of-sight velocity dispersion varies little over \sim 4 optical disk scale lengths , with \sigma _ { rad } \sim 20 km s ^ { -1 } .
We show that this is due to a combination of factors , including a decline in the radial component of the velocity ellipsoid at small galactocentric radii , and a gradient in the ratio of the vertical to radial velocity dispersion .
We use our data to derive the dynamical scale length of M33 ’ s disk , and the disk ’ s mass-to-light ratio .
Our most likely solution suggests that the surface mass density of M33 ’ s disk decreases exponentially , but with a scale length that is \sim 2.3 times larger than that of the system ’ s IR luminosity .
The large scale length also implies that the disk ’ s V -band mass-to-light ratio changes from M / L _ { V } \sim 0.3 in the galaxy ’ s inner regions to M / L _ { V } \sim 2.0 at \sim 9 kpc .
Models in which the dark matter is distributed in the plane of the galaxy are excluded by our data .