Spectroastrometric signals of the H₂ and Brγ lines of IRS 9A. The H₂ emission line appears to originate from the large-scale structure of IRS 9A while the Brγ line is formed at the core of IRS 9A. The spectroastrometric signal of the line displayed is weighted with w_f. The mean ratio F_{λ(continuum)}/F_λ(line) is of ~0.9 and ~0.5 for the H₂ and the Brγ line, respectively. The 2D spectral lines are also displayed in colors.