2025MNRAS.543..326U

We analyse 77 Fermi sources and their potential low-energy counterparts previously proposed in the literature. These sources were classified as active galactic nuclei (AGNs), mainly blazars, based on optical spectroscopy. The main goals of this work are to examine these associations, classify the blazars based on their multiwavelength spectral energy distributions (SEDs), and identify potential masquerading BL Lac objects. Through SED analysis, we assess whether the multiwavelength emission follows the characteristic double-peaked curve of blazars. Additionally, we propose the region of origin of the emission at different wavelengths, investigate the correlation between $\gamma$-ray and lower energy emission, and classify objects as low-, intermediate-, high-, or extreme high-synchrotron peaked (LSP, ISP, HSP, E-HSP) blazars. We search for masquerading BL Lacs, a class of flat-spectrum radio quasars where broad emission lines are swamped by non-thermal jet emission. The multiwavelength analysis revealed that the 64 radio-loud sources in our sample exhibit an SED with a double-peaked structure, typically ascribed to jet activity. Based on the synchrotron peak, 46 are HSP, 11 are ISP, and seven are LSP. We also found 9-18 masquerading BL Lac candidates ($\approx$15-30 per cent of the radio-loud sample). For the 13 radio-quiet unassociated gamma-ray sources, the SEDs do not exhibit the double-peaked structure typical of jetted AGNs. Further analysis ruled out star formation as the origin of the observed $\gamma$-ray emission, making its reconciliation with lower energy emission challenging. We explored alternative counterparts, identifying low-energy matches for seven sources, with no plausible counterparts found for the others.