ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Survey I-Survey I-Survey O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: the CO abundance model and the spatial resolution of the synthetic observations. We keep the velocity resolution fixed, to match that of the observations, because our main focus is the comparison of the simulation with the Outer Galaxy Survey. We will study the effect of varying both the spatial and the velocity resolution in a separate work. To look for possible trends related to the spatial resolution also in the observations, we divide the observed clouds into six slightly overlapping distance intervals, corresponding to the spatial resolution intervals [ x i /1.25, x i × 1.25], with x i = 0.5 × 2 i /2 pc, i = 0, ..., 5 (see Table 1 ). The number of observed clouds, N i , in the x i intervals is N 0, ...5 = 212, 584, 1936, 1816, 360, and 88. The third interval is the most populated one and has an average resolution of 1.04 pc, nearly identical to that of our fiducial model. This procedure of dividing the observed clouds into distance intervals is not exactly the same as reobserving with different resolutions clouds at a fixed distance, as in the synthetic observations. In the real observations, clouds are selected from maps containing objects with a rather large range of distances. Thus, the following comparison of the dependence on resolution of simulated and observed clouds should be considered of a qualitative nature. We first consider the dependence of the slopes of the mass and size distributions, β M and β R , respectively, on the CO abundance model and on the resolution, shown in Figures 8 and 9 . The squares show the mean spatial resolution and mean slope derived from the observations in each distance interval (the lowest-resolution bin is not shown because the power-law fit to the histograms has too large uncertainty due to the small number of clouds). The shaded areas give the 1 σ uncertainty in the estimated slope and the standard deviation of the spatial resolution values (the statistical uncertainty in the resolution, from the cloud distance uncertainty, may be even larger). Figure 8. Power-law exponents of the fits to the mass distributions vs. spatial resolution. Each plot shows a different model for the assumed relative abundance of CO, with the error bars giving the 1 σ uncertainty of the estimated slope. The square symbols are the values from the different distance intervals of the observational sample (see text), and the shaded areas show the standard deviation of the mean spatial resolution within each interval and the estimated 1 σ uncertainty of β M . The lowest-resolution interval of the observations and the lowest-resolution value of model V3 are not shown due to their excessive uncertainty. Figure 9. Power-law exponents of the fits to the size distributions vs. spatial resolution. As in the previous figure, each plot shows a different model for the assumed relative abundance of CO, with the error bars giving the 1 σ uncertainty of the estimated slope. The square symbols are the values from the different distance