Comparison between the spectrum of the companion and observed spectra of early M dwarfs. The blue shaded area is the flux density of the companion in the GPI H-band, in Jansky. The spectrum is the weighted average of the spectra extracted from the 76 GPI datacubes and the area encompass the uncertainties (derived from the uncertainty on the flux of the host star). The solid lines are three spectra from the CARMENES stellar spectral library, for various T_eff and log g values (evaluated in Hintz et al. 2019) and the dotted grey line is an additional spectrum of an M1 object.