First Results from the Diffuse X-ray Spectrometer (DXS)
Session 8 -- General ISM, Dust
Display presentation, Monday, 9:20-6:30, Pauley Room

## [8.07] First Results from the Diffuse X-ray Spectrometer (DXS)

W.T.Sanders, R.J.Edgar, M.Juda, W.L.Kraushaar, D.McCammon (U.Wisconsin--Madison)

The Diffuse X-ray Spectrometer (DXS) was flown as an attached Shuttle payload on the STS-54 Space Shuttle Endeavour mission in January 1993. DXS consists of two large-area Bragg crystal X-ray spectrometers that cover the 44 - 83 \AA\ wavelength range, and is designed to measure the spectrum of the low energy ($0.15 < E < 0.28\ {\rm keV}$) diffuse X-ray background with roughly 10 eV energy resolution and $15^\circ$ angular resolution. These diffuse X-rays are thought to be generated by a very hot ($10^6$ K) component of the interstellar medium that occupies a large fraction of the interstellar volume near the Sun.

We present spectra of the soft X-ray background in the energy range $0.15 < E < 0.28\ {\rm keV}$. We obtained spectra from 10 independent $15^\circ \times 15^\circ$ regions of the sky along a great circle $150^\circ$ long, which runs about $10^\circ$ north of the galactic plane through the third quadrant of the galaxy. The spectra show emission lines, the first direct evidence that the soft X-ray background arises in hot interstellar gas. The spectra of these regions are not all the same.

This work was supported by NASA contract NAS 5-26078.