[yt-users] Luminosity within r

Hi guys, I am trying to calculate the (X-ray) luminosity within a sphere of radius r:Lx = sum emissivity *dvol (within r) Suppose I have defined a new derived field XRayEmissivity, dependent on data['Density'] and data['Temperature']. How would you carry out that? I am trying to use BinnedProfile1D. However, it seems that the derived fields are computed only *after* binning, e.g.XRayEmissivity = <Density>**2 * <Temperature>^0.5 I don't want to use the averaged quantities (in each shell). I would like to compute the emissivity point by point, for each leaf block(very important for the luminosity). Is it possible? Thanks, as always! Max