lines by @wilson70 and @quireza06. We have taken into account that the plasma is distributed in a shell of 1.4 width and covers 20% of the area of the shell. Derived values are listed in Table 1, where we include the flux density at 1.46 GHz, the emission measure EM, the size of the structure in arcmin and pc, the rms electron density and the  mass and the ionized mass (including singly ionized He). Errors in electron densities and mases take into account an uncertainty of 20$\%$ in distance are about 50$\%$.

G353.2+0.9 and its close environs
=================================

Figure 5 reveals that the radio continuum emission in this region is concentrated in two bright clumps: the strongest one coincides with the optically bright region G353.2+0.9 (172447, –3410), while the other one is centered at (named G353.19+0.84 from hereon). A small blister linked to the O6.5V ((f)) star N36 ($\equiv$ Pis 24+3, @massey01) was detected by @bohigas04 inside G353.2+0.9. In the following subsections, we analyze the  region G353.2+0.9, the small blister linked to N36, and G353.19+0.84.

G353.2+0.9
----------

A comparison between Fig. 1 and 5 suggests that  and   emissions correlate with the radio emission. The sharp southern boundary detected both at 