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 _ { \ast } ) relation .
Our analysis includes also the galaxy outskirts ( up to > 4 effective radii , r _ { e } ) , a regime poorly explored by other Integral Field Spectrograph surveys .
Our observational strategy allows us to detect H \alpha out to more than 2.7 r _ { e } for 75 % of the sample .
Considering all galaxies together , the correlation between the \Sigma _ { SFR } and \Sigma _ { \ast } is quite broad , with a scatter of 0.3 dex .
It gets steeper and shifts to higher \Sigma _ { \ast } 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 _ { \ast } 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 _ { \ast } 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 _ { \ast } 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 _ { \ast } values vary of at most 0.7 dex across galaxies .
We investigate the relationship between the local and global SFR-M _ { \ast } relation , finding that the latter is driven by the existence of the size-mass relation .