SFR surface density vs. gas surface density. The diamonds mark the region in the disk of Malin 1 based on the radial averaged Σ_SFR we estimated as in Fig. 5. The Σ_gas for Malin 1 is from the eight H I data points of Lelli et al. (2010), after correcting for helium by a factor of 1.4. The color bar indicates the radius throughout the disk of Malin 1. The open black circles are normal spiral galaxies from de los Reyes & Kennicutt (2019, the Σ_gas from de los Reyes & Kennicutt 2019 uses the total atomic and molecular gas mass). The dashed black line and the shaded gray region show the de los Reyes & Kennicutt (2019) best-fit relation and 1σ scatter. The black squares show the LSB galaxies from Wyder et al. (2009) in Malin 1. They are marked as the open green star based on the UV Σ_SFR estimate from Wyder et al. (2009).