Measured correlated flux spectra (solid black line and error bars) for AFGL 2136, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra (solid black line and error bars) for AFGL 4176, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra (solid black line and error bars) for G305.20+0.21, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra (solid black line and error bars) for IRAS 13481-6124, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra (solid black line and error bars) for IRAS 17216-3801, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra (solid black line and error bars) for M8E-IR, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra for M17 SW IRS1, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation.

Measured correlated flux spectra (solid black line and error bars) for M17 UC1, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra (solid black line and error bars) for Mon R2 IRS2, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra for Mon R2 IRS3 A, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points.

Measured correlated flux spectra (solid black line and error bars) for Mon R2 IRS3 B, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra for MWC 300, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation.

Measured correlated flux spectra (solid black line and error bars) for NGC 2264 IRS1, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra for R CrA, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation.

Measured correlated flux spectra (solid black line and error bars) for R Mon, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra (solid black line and error bars) for S255 IRS3, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation. The dashed blue line shows a continuum fit to the red points, and the solid blue line shows the best fit to the absorption spectrum (see Sect. 4.3).

Measured correlated flux spectra for V921 Sco, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation.

Measured correlated flux spectra for V1028 Cen, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation.

Measured correlated flux spectra for VY Mon, in order of increasing projected baseline. The caption shows the projected baseline and position angle of each observation.