select the DR9 QSOs in HeRS and HeLMS to be within the Stripe 82 region ($-1.25^{\circ} <$ Dec $< 1.25^{\circ}$) and assume the angular completeness is uniform. In Table 1, we list the number of selected SDSS DR7 and DR9 QSOs found in the HeRS, HeLMS, Boötes, Lockman-SWIRE and [*XMM*]{}-LSS regions. Note that the number of DR9 QSOs in the HeRS and HeLMS Stripe 82 regions undergoes a final selection in Section 3.2.

![image](hers_outline_dr7_9_qso.eps){height="3.3in" width="3.45in"} ![image](helms_outline_dr7_9_qso.eps){height="3.3in" width="3.35in"}

The cross-correlation between QSO and CIB
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Cross-correlation estimator
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The cross-correlation of the two fields of interest $\rho_1$ (representing the quasar number density field) and $\rho_2$ (representing the CIB) is $$\xi=\left< \delta_1 \delta_2 \right>=\frac{1}{\overline{\rho}_1 \overline{\rho}_2} \left<(\rho_1 - \overline{\rho}_1)(\rho_2 - \overline{\rho}_2)\right>,$$ where $\overline{\rho}_1$ is the mean number density of QSOs and $\overline{\rho}_2$ is the mean value of the CIB. The SPIRE maps, $\rho^\prime_2$, can be used to estimate $\rho_2$ but have been mean-subtracted, i.e. the maps have a mean of zero $\overline{\rho^\prime_2}=0$. The two quantities are thus related $\rho_2=\rho^\prime_2+C$, where $C$ is the unknown DC level of the map. To proceed we assume a value for $C$ and add this to the map[^9] and will show that the choice of $C$ only affects 