model the Fermi bubbles. compiled a subset of the flux-filtered sample with additional spatial screening criteria to reduce any residual emission from sources other than the LB and Galactic hot halo. To achieve this, they removed observations within 0.5$\arcdeg$ of potential bright X-ray sources (see Table 1 in for the types of sources) or within 10$\arcdeg$ of the Galactic plane, and sight lines near the Fermi bubbles ($|l| \leq\ 22\arcdeg$, $|b| \leq\ 55\arcdeg$). This resulted in a subsample of 649 observations from the flux-filtered sample.

The *XMM-Newton* data used in this study are the same as those used in , but including the sight lines near the Fermi bubbles. We start with the flux-filtered sample and still exclude sight lines near bright X-ray sources or within 10$\arcdeg$ of the Galactic plane. These screening criteria result in a total of 683 *XMM-Newton* measurements distributed across the sky, with 34 measurements passing near or through the bubbles’ gamma-ray edge.

*Suzaku* Observations and Data Reduction {#subsection.suz_chap_fb}
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We compiled an initial *Suzaku* target list of all observations that were publicly available as of 2015 January and near the Fermi bubbles. This included any observations with Galactic coordinates $|l| \leq\ 25\arcdeg$ and $10\arcdeg \leq 