J-PLUS: Spectroscopic validation of H

Aims. We present a dedicated automated pipeline to construct spatially resolved emission Hα+[NII] maps and to derive the spectral energy distributions (SEDs) in 12 optical filters (five broad and seven narrow and medium) of Hα emission line regions in nearby galaxies (z < 0.0165) observed by the Javalambre Photometric Local Universe Survey (J-PLUS). Methods. We used the J0660 filter of 140 Å width centered at 6600 Å to trace H α + [NII] emission, and r and i broad bands were used to estimate the stellar continuum. We created pure emission line images after the continnum subtraction, where the Hα emission line regions were detected. This method was also applied to integral field unit (IFU) spectroscopic data from PHANGS-MUSE, CALIFA, and MaNGA surveys by building synthetic narrow bands based on J-PLUS filters. The studied sample includes the cross-matched catalog of these IFU surveys with the J-PLUS third data release (DR3), amounting to two PHANGS-MUSE, 78 CALIFA, and 78 MaNGA galaxies at z < 0.0165, respectively. Results. We compared the Hα+[NII] radial profiles from J-PLUS and the IFU surveys, finding good agreement within the expected uncertainties. We also compared the SEDs from the emission line regions detected in J-PLUS images, reproducing the main spectral features present in the spectroscopic data. Finally, we compared the emission fluxes from the J-PLUS and IFU surveys accounting for scale differences, finding a difference of only 2% with a dispersion of 7% in the measurements. Conclusions. The J-PLUS data provide reliable spatially resolved Hα+[NII] emission maps for nearby galaxies. We provide the J-PLUS DR3 catalog for the 158 galaxies with IFU data, including emission maps, SEDs of star-forming clumps, and radial profiles.