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تسجيل مستخدم جديدGASP. XX. From the loose spatially-resolved to the tight global SFR-Mass relation in local spiral galaxies
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Exploiting the sample of 30 local star-forming, undisturbed late-type galaxies in different environments drawn from the GAs Stripping Phenomena in galaxies with MUSE (GASP), we investigate the spatially resolved Star Formation Rate-Mass ({Sigma}SFR-{Sigma}_star) relation. Our analysis includes also the galaxy outskirts (up to >4 effective radii, re), a regime poorly explored by other Integral Field Spectrograph surveys. Our observational strategy allows us to detect H{alpha} out to more than 2.7re for 75% of the sample. Considering all galaxies together, the correlation between the {Sigma}SFR and {Sigma}_star is quite broad, with a scatter of 0.3 dex. It gets steeper and shifts to higher {Sigma}_star values when external spaxels are excluded and moving from less to more massive galaxies. The broadness of the overall relation suggests galaxy-by-galaxy variations. Indeed, each object is characterized by a distinct {Sigma}SFR-{Sigma}_star relation and in some cases the correlation is very loose. The scatter of the relation mainly arises from the existence of bright off-center star-forming knots whose {Sigma}SFR-{Sigma}_star relation is systematically broader than that of the diffuse component. The {Sigma}SFR-{Sigma}tot gas (total gas surface density) relation is as broad as the {Sigma}SFR-{Sigma}_star relation, indicating that the surface gas density is not a primary driver of the relation. Even though a large galaxy-by-galaxy variation exists, mean {Sigma}SFR and {Sigma}_star values vary of at most 0.7 dex across galaxies. We investigate the relationship between the local and global SFR-M_star relation, finding that the latter is driven by the existence of the size-mass relation.
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