the mean or median $q$ of detected massive and dwarf galaxies, finding marginal difference (Table \[tab:stats\]). However, a two-sample Kolmogorov-–Smirnov (K–S) test to the $q$ distributions of massive and dwarf galaxies gives the statistics of 0.38 with $p=0.30$, not sufficient to rule out the null hypothesis.

![The $q$ value as a function of equivalent 60[$\,\mathrm{\mu m}$]{} luminosity $L_\mathrm{60\mu m,equiv}$ for detections. The symbol scheme is the same as Figure \[fig:frc\]. The grey lines are the same as in Figure 6 of @2001ApJ...554..803Y: the solid line is $q=2.34$ and the dotted lines show the value corresponding to 5 times larger radio and FIR flux density than expected.[]{data-label="fig:lir_q"}](fig/lir_q.pdf){width="8cm"}

Figure \[fig:lir\_q\] shows the $q$ as a function of equivalent 60[$\,\mathrm{\mu m}$]{} luminosity, which is the luminosity contribution from IRAS 60[$\,\mathrm{\mu m}$]{} band to the total FIR luminosity, defined in Equation 3 of @2001ApJ...554..803Y. It provides a better view of the comparison between massive and dwarf galaxies, for detections. It is clear that the low luminosity systems, mostly dwarf galaxies, have larger $q$. If we split the detection sample at $L_\mathrm{60\mu m,equiv}=3\times10^8\,\mathrm{L_\odot}$, we find that luminous and faint galaxies have different $q$ ($2.38\pm0.07$ versus $2.64\pm0.08$; two-sample K-S test statistics 0.55 with $p=0.05$). The lack 