Planetary nebulae (PNe) are powerful probes of their host galaxies; however, their detection outside the Milky Way is significantly more challenging. We investigate the PN population of M33 using data from the J-PLUS survey (DR3), a 12-band photometric dataset well suited for identifying Hα emitters. While only 13 of the 143 known PNe in M33 have photometry available in the J-PLUS catalog, by performing source extraction directly on the J-PLUS images we recovered photometry for over one hundred PNe, including the 13 already cataloged, thus revealing the hidden population.
Color-color diagrams allowed us to identify possible PN candidates, most consistent with emission-line sources, and even a potential halo PN when combining radial velocities from the literature with criteria previously applied to Milky Way halo PNe.
This work represents the first attempt to explore extragalactic PNe with multi-band photometric surveys such as J-PLUS, S-PLUS, and J-PAS, highlighting their strong potential for PN research in nearby galaxies.

The discovery of high ionization emission lines in both high-redshift galaxies and nearby, metal-poor dwarf galaxies has questioned the origin of He II ionizing radiation. Current stellar population synthesis models consistently fail to reproduce the necessary ionizing fluxes, pointing to a fundamental gap in our understanding of stellar feedback and its role in cosmic reionization. Classical Wolf-Rayet (WR) stars are hot, evolved massive stars with depleted hydrogen. WR stars with prominent Nitrogen emission lines in their spectra are called WN type, further sub-divided as 'early' (WNE) when showing emission from high ionization species (e.g., He II, N V). WNE stars at low metallicity are huge contributors to the HeII ionizing flux of their host galaxy. However, the presence of WNE stars in integrated environments can be diluted, making their direct spectroscopic detection challenging. In this talk, I will directly compare stellar spectral diagnostics for the resolved WNE stars in our nearest low-metallicity dwarf galaxy, the SMC, with integrated nebular diagnostics from the Local Volume Mapper integral field survey. I will discuss the implications of our unexpected findings for population synthesis models and galaxy evolution.