Morphology rather than environment drives the SFR-Mass relation in the
  local universe
  Exploiting a sample of 680 star-forming galaxies from the Padova-Millennium
GalaxyGroup Catalog (PM2GC) (Calvi et al. 2011) in the range 0.038<z<0.104, we
present a detailed analysis of the Star Formation Rate (SFR)-stellar mass
(M_star) and specific SFR(SSFR)-M_star relations as a function of environment.
We adopt three different parameterizations of environment, to probe different
scales. We consider separately 1) galaxies in groups, binary and single
systems, defined in terms of a Friends-of-Friends algorithm, 2) galaxies
located at different projected local densities, 3) galaxies in haloes of
different mass. Overall, above logM_ast/M_sun>10.25 and SSFR>10^{-12} yr^{-1},
the SFR-M_ast and SSFR-M_ast relations do not depend on environment, when the
global environment is used, while when the halo mass is considered, high mass
haloes might have a systematically lower (S)SFR-M_ast relation. Finally, when
local densities are exploited, at any given mass galaxies in less dense
environments have systematically higher values of SFR. All the relations are
characterized by a large scatter ({\sigma}~0.6), which is dueto the coexistence
of galaxies of different morphological types. Indeed, at any given mass,
late-types are characterized by systematically higher values of SFR and SSFR
than S0s and ellipticals. Galaxies of the same morphology show similar trends
in all the environments, but their incidence strongly depends on environment
and on the environmental parametrization adopted, with late-types generally
becoming less common in denser environments, contrasted by the increase of
ellipticals and/or S0s. Our results suggest that in the local universe
morphology and local interactions, probed by the local density
parameterization, have dominant roles in driving the characteristics of the
SFR-M_ast relation.
