Model of the SED of NGC 7293 (continuous line) considering both free-free (dashed line) and thermal dust emission (dotted line). Ancillary radio measurements, obtained with different instruments, are shown as open squares (reference numbers given in Table 1: 2, 3, 6, 7, 16, 17, 18, 19, 23, 29 and 52), WMAP 7-year data as open triangles, aperture photometry from IRIS as filled triangles, and Planck data are shown as red squares. IRIS data at 12 m and 25 m, which are contaminated by emission lines, are also shown in the plot for completeness, but were not considered in the fitting procedure (see text).