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tokens: source at its given velocity (within 15 km s −1 ), position (within 5 arcmin), and derived a velocity width and size within our cuts used in Section 2.2 . We recovered every injected source at high velocities, where Galactic emission is the weakest, and nearly every source at low velocities and Leo T velocities (97% and 82%, respectively), the latter of which is lower because Leo T’s velocity is often within the region of average Galactic emission >1 K which we purposely ignored. Nevertheless, we can confidently say that SoFiA would successfully detect Leo T at its actual distance in the vast majority of our search area. We next wanted to determine how accurate our detection limit of Leo T-like objects was, based on our observed flux distribution. To do this, we performed the same procedure as before with two alterations; we scaled the peak flux of the injected source to a larger distance (from 0.5 to 1 Mpc), and we reduced the size of the injected source to better correspond to a more distant galaxy. At high velocities, the detection fraction dropped to its lowest value of 86% at 1 Mpc, but the difference at low and Leo T velocities is much more drastic, as shown in the first three rows of Table 3 (with Mass = 1 Leo T). Note, however, that a typical local group galaxy that is 1 Mpc away has a velocity closer to our high-velocity case than either of the lower-velocity cases. In other words, the region of distance-velocity space where our detection fraction is lowest also probably contains the smallest number of dwarf galaxies. We also tried reducing the injected sources’ size, which results in a ∼10% drop in the detection fraction at lower velocities compared to the same test without changing the size, meaning the dominant reason for the overall drop is the reduction in flux caused by increasing distance. In the bottom three rows of Table 3 we inject sources with successively larger multiples of Leo T’s mass to determine how complete we are out to 1 Mpc. We note that we would detect ≈50% of galaxies at lower velocities with only 2 times Leo T’s mass, and ≈66% of those with 3 times Leo T’s mass. 6 6 At 4 times Leo T’s mass we naturally recover the same detection fractions as the first row of Table 3 , because multiplying the mass of the third row by 4 is equivalent to halving the third row’s distance in terms of H i flux. Table 3 Detection Fraction of Sources Injected at or beyond a Distance of 500 Note. The H i mass of Leo T is . The last row of 10 times Leo T’s mass is an exception to the previous rows in that the size and w 50 cuts we apply are the dominant cause for reduction in recovered sources in regions significantly contaminated by Galactic emission at low velocities. Without the size and w 50 cuts, the detection fractions are all >92%. The higher level of background noise at low latitude causes SoFiA to chop off the outer regions of the object in its size calculation. Therefore our size cut may lead us to miss some dwarf galaxies