Distribution of the X-ray peak luminosity of Swift sources matching a galaxy from GLADE. Only sources with at least two quality rules and reasonable quality flags are selected. The blue bars show the subset of off-center sources, i.e., sources whose error circle does not match the galaxy center. The dark gray bars show a subset of these sources, made of good XRB candidates (candidates with ℙ(XRB) > 2ℙ(c) for every other class c).