Radial gas metallicity and stellar profile. Top: metallicity gradient in Malin 1. The brown hexagons show the extended disk regions of Malin 1 discussed in Sect. 3.3. The observed metallicities shown here are based on the Marino et al. (2013) N2 calibrator. The dot-dashed magenta line is the best-fit model of Malin 1, with a circular velocity of 380 km s⁻¹ and a spin parameter of 0.58, obtained after a refitting following Boissier et al. (2016). Bottom: optical surface brightness profile of Malin 1 in the g- (solid black line) and i-band (dot-dashed black line) from Boissier et al. (2016). The secondary axis on the right shows the g − i color profile from Boissier et al. (2016) as the dotted red line. The stellar profiles are shown only until the radial range for which we have a metallicity estimate. The vertical dashed blue line is the i-band surface brightness break radius from Junais et al. (2020).