Energy Spectra of the Soft X-Ray Diffuse Emission in Fourteen Fields Observed with Suzaku

Abstract

The soft diffuse X-ray emission of twelve fields observed with Suzaku are presented together with two additional fields from previous analyses. All have galactic longitudes 65$^\circ $$\lt$$\ell$$\lt$ 295$^\circ $ to avoid contributions from the very bright diffuse source that extends at least 30$^\circ $ from the Galactic center. The surface brightnesses of the Suzaku nine fields for which apparently uncontaminated ROSAT All Sky Survey (RASS) were available were statistically consistent with the RASS values, with an upper limit for differences of 17 $\times$ 10$^{-6}$cs$^{-1}$arcmin$^{-2}$ in R45-band. The OVII and OVIII intensities are well correlated to each other, and OVII emission shows an intensity floor at $\sim$2 photonss$^{-1}$cm$^{-2}$str$^{-1}$ (LU). The high-latitude OVIII emission shows a tight correlation with excess of OVII emission above the floor, with (OVIII intensity) $=$ 0.5 $\times$ [(OVII intensity) $-$ 2LU], suggesting that temperatures averaged over different line-of-sight show a narrow distribution around $\sim$0.2 keV. We consider that the offset intensity of OVII arises from the Heliospheric solar wind charge exchange and perhaps from the local hot bubble, and that the excess OVII (2–7LU) is emission from more distant parts of the Galaxy. The total bolometric luminosity of this galactic emission is estimated to be 4 $\times$ 10$^{39}$ergs$^{-1}$, and its characteristic temperature may be related to the virial temperature of the Galaxy.

Studying the Interstellar Medium and the Inner Region of NPS/Loop 1 With Shadow Observations Toward Mbm36

“…Ne overabundance, together with Fe overabundance, was also reported by Yoshino et al (2009). In our analysis, however, we could not constrain the Fe abundance and we have been forced to set it at Fe/O=1 solar.…”

“…This excess emission can be explained as an overabundance of Ne and/or Fe (Yoshino et al 2009) or as the presence of an additional warmer thermal component. Both cases have been reported in the literature.…”

Apparent high metallicity in 3–4 keV galaxy clusters: the inverse iron-bias in action in the case of the merging cluster Abell 2028

“…We checked the observation for contamination by solar wind charge exchange. The ACE SWEPAM 1 proton flux was less than 4 × 10 8 protons s −1 cm −2 which is typical of the quiescent Sun (e.g., Snowden et al 2004;Fujimoto et al 2007;Yoshino et al 2009), and the light curve accumulated in a 0.5−2 keV energy band (after soft proton flares removal) did not show any variability. The spectra of the out-of-field-of-view events of CCD 4 and 5 of MOS1 and CCD 5 of MOS 2 showed an anomalously high flux in the soft band (see ) so they were therefore excluded from our analysis.…”

On the Hot Gas Content of the Milky Way Halo

“…Yoshino et al (2009) studied the soft, diffuse X-ray emission in 12 fields observed with the Suzaku X-ray Telescope. The Galactic longitudes and latitudes are similar to those XMM fields, i.e., high latitudes and away from the direction of the Galactic center, except two fields at b = 10…”