def METHOD_NAME(self, pos, r_catch):
    dist = np.fabs(np.array(self.system.part.all().pos) - pos)
    # check smaller distances via PBC
    dist = np.where(
        dist > 0.5 * self.system.box_l, self.system.box_l - dist, dist)
    dist = np.sum(dist**2, axis=1)
    return np.where(dist < r_catch**2)[0]