Brian Jackson edited subsection_Converting_Between_the_Observed__.tex  over 8 years ago

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\subsection{Converting Between the Observed and Actual Parameter Distributions}  Consider a distribution of observed values $\rho(\Gamma_{\rm obs}, P_{\rm obs}) = \dfrac{d^2N}{d\Gamma_{\rm obs}\ dP_{\rm obs}}$. The small number of devils $dN = f\ \rho(\Gamma_{\rm obs}, P_{\rm obs})\ d\Gamma_{\rm act}\ dP_{\rm act}$ contributing are those that had closest approach distances between $b$ and $b + db$ of the detector. Thus, we can convert $\rho(\Gamma_{\rm act}, P_{\rm act})$ to $\rho(\Gamma_{\rm obs}, P_{\rm obs})$ by integrating the former density over $b$ and accounting for the bias and distortion effects. To calculate the integral, we also need to re-cast the upper limit to express the maximum possible radial distance, i.e. the distance at which $P_{\rm act} = P_{\rm max}$. Using Equation \ref{eqn:b} and making the replacements $P_{\rm act} = P_{\rm max}$ and  $\Gamma_{\rm act} = \left( P_{\rm obs}/P_{\rm act} max}  \right)^{1/2} \Gamma_{\rm obs}$ from Equation \ref{eqn:P_obs_Gamma_obs}and $P_{\rm act} = P_{\rm max}$  gives $b(\Gamma_{\rm obs}, P_{\rm obs}) = \left(\Gamma_{\rm obs}/2\right) \left[ \left(P_{\rm max} - P_{\rm obs}\right)/P_{\rm max} \right]^{1/2}$. The integral to convert from $\rho({\rm act}) \equiv \rho(P_{\rm act}, \Gamma_{\rm act})$ to $\rho({\rm obs}) \equiv \rho(\Gamma_{\rm obs}, P_{\rm obs})$ is then \begin{equation}  \label{eqn:convert_from_actual_to_observed_density}