Erratum for: A&A, 696, A148 (2025), https://doi.org/10.1051/0004-6361/202554180

The analytic computation of the column densities for the model clumps in the photon-dominated region (PDR) modeling in Sect. 5.3 used an incorrect clump mass-to-column conversion, dividing by the clump radius instead of the square of the clump radius. Consequently, Figs. 9 and B.1, which normalize the intensities by the gas column density and indicate the parameter range of the observed column densities, were wrong. The corrected figures (Figs. 1 and 2 here) show the correct steeper contours of constant column density in the density-mass parameter space.

With the correct column densities a limitation of the observed data to CO, [C I], [C II], and the total gas column results in a solution space between low-mass clumps with densities of about 10⁵ cm⁻³ and ten times thinner clumps of about one solar mass. However, our main conclusion is confirmed: that when including the information from ¹³CO 2-1 and C¹⁸O 2-1, all models are ruled out. The specific intensities of those two lines are only met for low-mass, low-density or high-mass, high-density clumps. Both are incompatible with the observational data of CO and [C I]. The correct normalization still shows no parameter space that matches all observed intensities, even within a factor of ten.

© The Authors 2025

All Figures

Fig. 1 Integrated line intensities predicted by the KOSMA-τ PDR model relative to the column density of the model clumps for a UV radiation field of 1χ0. The panels from left to right show CO 2-1, 13CO 2-1, C18O 2-1, [C I] 1-0, and [C II]. The white, gray, and black lines indicate the minimum, mean, and maximum of the observed ratio. For [C II] we only have an upper limit. The red and orange contours indicate the lowest and highest column density in the region obtained from the dust observations.

In the text

	Fig. 2 Same as Fig. 1 but for a UV radiation field of 10χ0.
In the text