This plot shows the dense-gas star-formation relationships (star formation rate versus the mass of dense-gas) for all samples observed in HCN J=4-3 line emission, including the MALATANG survey data used in this work.
The straight lines are linear fits (in logarithmic scale) from different works, which are all close to unity. This result implies that, over a broad dynamical range of galactic properties, the high transition dense-gas molecular-line is good tracers of on-going star formation activity in galaxies.