2008ApJ...674..209K

We have obtained an XMM-Newton spectrum of the diffuse X-ray emission toward (ℓ,b)=(111.14°,1.11°), a line of sight with a relatively simple distribution of absorbing clouds: >9x10¹⁹/cm2 at R>170 pc, a 6x10²¹/cm2 molecular cloud at 2.5-3.3 kpc, and a total column of 1.2x10²²/cm2. We find that the analysis of the XMM-Newton spectrum in conjunction with the ROSAT All-Sky Survey (RASS) spectral energy distribution for the same direction requires three thermal components to be well fit: a ``standard'' Local Hot Bubble component with kT=0.095, a component beyond the molecular cloud with kT=0.57, and a component before the molecular cloud with kT=0.24. The strength of the O VII 0.56 keV line from the Local Hot Bubble, 1.75±0.7 photons/cm2/s/sr, is consistent with other recent measures. The 0.24 keV component has an emission measure of 0.0021±0.0006/cm6 pc and is not localized save as diffuse emission within the Galactic plane. Rough calculations show that only about a quarter of this component is due to unresolved stellar emission; it is the best candidate for a pervasive hot medium. The spatial separation of the ∼0.2 keV component from the ∼0.6 keV component suggests that the spectral decompositions of the emission from late-type spiral disks found in the literature do represent real temperature components rather than reflecting more complex temperature distributions.