A multiband catalog of infrared-excess sources in the Vela–Carina Region: VVVX, DECaPS, and GLIMPSE

Large multiwavelength surveys of the Galactic midplane enable the identification of sources exhibiting infrared excess, a signature of circumstellar material; however, this task is hindered by high extinction and severe source crowding. We aim to construct a homogeneous catalog of infrared-excess candidates in a ∼ 7.0 deg 2 field of the Vela–Carina region and to characterize the nature of their excess emission through spectral energy distribution (SED) analysis. We combine optical photometry from the Dark Energy Camera Plane Survey (DECaPS), near-infrared (NIR) photometry from the VISTA Variables in the Vía Láctea eXtended survey (VVVX), and mid-infrared (MIR) photometry from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) using hierarchical positional cross-matching. Infrared-excess candidates are selected based on photometric quality criteria and MIR color diagnostics. Their SEDs are analyzed with the Virtual Observatory SED Analyzer (VOSA) using grids of theoretical stellar atmosphere models. Photogeometric distance estimates were adopted for the physical characterization of the sources, while variability information from Gaia Data Release 3 (Gaia DR3) and the Near-Earth Object Wide-field Infrared Survey Explorer Reactivation mission (NEOWISE) was used as a complementary diagnostic. From the matched VVVX–GLIMPSE–DECaPS catalog of 249 719 sources, we identify 1 512 objects exhibiting MIR excess, of which 191 have complete 12-band photometry with S/N > 10 , enabling detailed SED analysis. For sources with available estimates, the adopted photogeometric distances are statistically consistent with the corresponding geometric distances for nearly the entire sample. The SED analysis independently supports the MIR-excess nature of the majority of the selected sources, indicating infrared emission beyond that expected from stellar photospheres alone. Approximately 15% of the sources are flagged as variable by Gaia , while NEOWISE light curves reveal MIR variability at the level of a few tenths of a magnitude. Comparisons with previously published young stellar object (YSO) and variability-selected catalogs show varying degrees of overlap, with particularly limited overlap with variability-selected samples, indicating that MIR-excess selection provides a complementary route to identifying candidate YSOs in the Vela–Carina region. The resulting catalog provides a well-defined sample of MIR-excess sources with homogeneous multiband photometry, SED characterization, distance information, and variability diagnostics, and constitutes a robust foundation for future spectroscopic and time-domain studies.