Understand
We use new and updated gas and dust-corrected SFR surface densities to revisit the integrated star formation law for local "quiescent" spiral, dwarf, and low-surface-brightness galaxies.
- Using UV-based SFRs with individual IR-based dust corrections, we find that "normal" spiral galaxies alone define a tight $\Sigma_{(\textrm{HI}+\textrm{H}_{2})}$-$\Sigma_{\textrm{SFR}}$ relation described by a $n=1.41^{+0.07}_{-0.07}$ power law with a dispersion of $0.28^{+0.02}_{-0.02}$ (errors reflect fitting and statistical uncertainties).
- The SFR surface densities are only weakly correlated with HI surface densities alone, but exhibit a stronger and roughly linear correlation with H$_{2}$ surface densities, similar to what is seen in spatially-resolved measurements of disks.
- However, many dwarf galaxies lie below the star formation law defined by spirals, suggesting a low-density threshold in the integrated star formation law.