Locus of the column density of neutral hydrogen (N _H) and temperature (T) that best reproduce the fluxes of Brγ and the Pfund 19 (Table 3). The red solid line is for Brγ while the blue solid line represents the ratio of the Pfund 19 over the Brγ. The dashed lines are the 3σ uncertainties plotted only from one side. The ratios of the other Pfund lines are not plotted because they are very similar to that for Pfund 19.