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Arxiv: Physical properties of strong 1 < z < 3 Balmer and Paschen lines emitters observed with JWST Published: 4/15/2024 1:47:00 PM Updated: 4/16/2024 5:03:38 PM

Paper abstract: The ultraviolet continuum traces young stars while the near-infrared unveilsolder stellar populations and dust-obscured regions. Balmer emission linesprovide insights on gas properties and young stellar objects but are highlyaffected by dust attenuation. The near-infrared Paschen lines suffer less dustattenuation and can be used to measure star formation rates (SFRs) instar-forming regions obscured by dust clouds. We select 13 sources betweenredshifts 1 and 3 observed with HST, JWST/NIRCam and NIRSpec based on theavailability of at least one Balmer and one Paschen line with S/N > 5. With anewly-developed version of CIGALE, we fit their hydrogen line equivalent widths(EWs) and photometric data. We assess the impacts of the removal ofspectroscopic data by comparing the quality of the fits of thespectro-photometric data to those with photometric data only. We compare thesingle (BC03) vs binary (BPASS) stellar populations models in the fittingprocess of spectro-photometric data. We derive the differential attenuation andexplore different attenuation recipes by fitting spectro-photometric data withBC03. For each stellar model and for each input dataset (with and without EWs),we quantify the deviation on the SFRs and stellar masses from the "standard"choice. On average, the SFRs are overestimated and the stellar masses areunderestimated when EWs are not included as input data. We find a majorcontribution of the H{\alpha} emission line to the broadband photometricmeasurements of our sources, and a trend of increasing contribution withspecific SFR. Using the BPASS models has a significant impact on the derivedSFRs and stellar masses. We show that a flexible attenuation recipe providesmore accurate estimates of the dust attenuation parameters, especially thedifferential attenuation which agrees with the original value of Charlot & Fall(2000).