The distribution of local star formation activity as a function of
  galaxy stellar mass, environment and morphology
  We present a detailed inventory of star formation in the local Universe,
dissecting the cosmic star formation budget as a function of key variables that
influence the star formation rate (SFR) of galaxies: stellar mass, local
environment and morphology. We use a large homogeneous dataset from the SDSS to
first study how the star-formation budget in galaxies with stellar masses
greater than $\log (\textrm{M}_{*}/\textrm{M}_{\odot}) = 10$ splits as a
function of each parameter separately. We then explore how the budget behaves
as a simultaneous function of these three parameters. We show that the bulk of
the star formation at $z<0.075$ ($\sim$65 per cent) takes place in spiral
galaxies, that reside in the field, and have stellar masses between $10 < \log
(\textrm{M}_{*}/\textrm{M}_{\odot}) < 10.9$. The ratio of the cosmic star
formation budget hosted by galaxies in the field, groups and clusters is
21:3:1. Morphological ellipticals are minority contributors to local star
formation. They make a measurable contribution to the star formation budget
only at intermediate to high stellar masses, $10.3< \log
(\textrm{M}_{*}/\textrm{M}_{\odot}) < 11.2 $ (where they begin to dominate by
number), and typically in the field, where they contribute up to $\sim$13 per
cent of the total star-formation budget. This inventory of local star formation
serves as a $z\sim0$ baseline which, when combined with similar work at high
redshift, will enable us to understand the changes in SFR that have occurred
over cosmic time and offers a strong constraint on models of galaxy formation.
