LAT view of SNRs Kes 78, G032.4+00.1, and the PeVatron candidate PWN G32.64+0.53

G032.8-00.1 (or Kes 78) and G032.4+00.1 are two adjacent in the sky, apart by 0.4 deg, supernova remnants (SNRs). While both SNRs have been extensively studied in radio and X-ray wavelengths, their $\gamma$-ray characteristics remain underexplored. The latest 4FGL-DR4 catalog indicates a GeV $\gamma$-ray excess in this region, though its origin is not yet determined. Utilizing $\sim16.2$ years of Fermi-LAT data, we conduct a comprehensive investigation of the $\gamma$-ray emission from this area, presenting the first detailed morphological and spectral analysis of the $\gamma$-ray emission associated with these two SNRs. Our findings suggest that these remnants are the most plausible sources for the observed excess, which displays two distinct maxima spatially coincident with the SNRs. We detect $\gamma$-ray emission from both SNRs at energies $>1$ GeV with a significance level of approximately 9$\sigma$. The spectral analysis together with the apparent interaction of the remnants with nearby molecular gas supports a hadronic origin for the $\gamma$-ray emission from both remnants. This conclusion is further substantiated by the multiwavelength spectral energy distribution (SED) modeling conducted in this study. This discovery positions G032.4+00.1 within the closed group of confirmed $\gamma$-ray SNRs exhibiting a non-thermal spectral component in the X-ray band. Additionally, the first statistically significant detection at the $4.5\sigma$ level in the 10-100~GeV energy band was achieved for the nearby pulsar wind nebula PWN G32.64+0.53, associated with pulsar PSR J1849-0001.