Discovery of 17 New GeV Blazar Candidates through Spatial Cross-Matching between Roma-BZCAT and 4FGL-Xiang-DR2

Abstract: Using 16 years of Fermi-LAT data and resources from the NASA/IPAC Extragalactic Database (NED), we constructed two high-precision catalogs: the updated 4FGL-Xiang-DR2 (DR2) and a supplementary version of the fifth edition of Roma-BZCAT (5BZCAT_err), both featuring refined positional uncertainties. We performed a spatial cross-identification between the two catalogs and developed a systematic three-step analytical pipeline: (1) efficient retrieval of positional uncertainties and multi-wavelength fluxes from 5BZCAT_err, (2) calculation of spatial association probabilities with DR2, and (3) statistical modeling of multi-band fluxes, using the Box--Cox transformation and a truncated normal distribution. Through this process, we identified 17 new blazar candidates. Fermi-LAT analysis reveals that, except for J1043.7+5323, which exhibits significant flux variability above 100 MeV, the remaining sources display stable fluxes, without apparent spatial extension or spectral curvature. Multi-wavelength flux modeling shows that 15 of the 17 sources fall within the 2$\sigma$ confidence interval of the distribution model, demonstrating strong statistical consistency with known blazar samples. As Fermi-LAT data continues to accumulate, the remaining two sources are expected to converge toward the high-confidence region, providing further support for the common-source hypothesis.