Search of Extended Objects in the Southern Sky (SExOSS) using S-PLUS DR1: photometric characterization of extragalactic sources

The SExOSS (Search of Extended Objects in the Southern Sky) project is planning to study a large sample of extended sources in the southern sky. Using The Southern Photometric Local Universe Survey (S-PLUS) data taken in 12 filters (5 broad + 7 narrow bands), the first step will consist to analyze the photometric relationships shown using the broandband magnitudes, and through a deeper characterization made from narrow band filters behaviour. Such a characterization could reveal the existence of new photometric relationships involving one or more of those narrow band magnitudes available in this survey. In the present work, the first results obtained are shown, on a sample of extended sources included in the first data release (DR1) of S-PLUS. This first release corresponds to the Stripe-82 sky area previously observed by the Sloan Digital Sky Survey (SDSS). For our analysis, we considered a subsample of objects that had spectra in the SDSS to be able to perform a spectroscopic classification of their internal activity (galaxies with/without star formation, active nuclei, etc.) and then searching for links between the properties shown in the narrow band photometry. The S-PLUS DR1 has more than 3×10⁵ sources, of which about 3×10⁴ have been found to be extended and matched in the SDSS. We present here the results obtained on a subsample selected by considering threshold values for the signtal-to-noise level in both the SDSS spectra and the magnitude value in the DR1 database, on which a blind classification of internal activity was carried out.