Rauw, G. ; Blomme, R. ; Waldron, W. L. ; Naze, Y. ; Harries, T. J. ; Chapman, J. M. ; Corcoran, M. F. ; Detal, A. ; Gosset, E. ; Pittard, J. M. ; Pollock, A. M. T. ; Runacres, M. C. ; Sana, H. ; Stevens, I. R. ; Van Loo, S. ; Vreux, J. M.

published in NASA STI/Recon Technical Report N, 2 (2001)

Abstract: We report preliminary results of an XMM-Newton observation of the 04 V star 9 Sgr (= HD 164794). 9 Sgr is one of a few single OB stars that display a non-thermal radio emission attributed to synchrotron emission by relativistic electrons. Inverse Compton scattering of photospheric UV photons by these relativistic electrons is a priori expected to generate a non-thermal power-law tail in the X-ray spectrum. Our EPIC and RGS spectra of 9 Sgr suggest a more complex situation than expected from this 'simple' theoretical picture. Furthermore, soft-band EPIC images of the region around 9 Sgr reveal a number of point sources inside the Lagoon Nebula (M8). Most of these sources have optical counterparts inside the very young open cluster NGC 6530 and several X-ray sources are associated with low and intermediate mass pre-main sequence stars. Finally, we also detect (probably) diffuse X-ray emission from the Hourglass Region that might reveal a hot bubble blown by the stellar wind of Herschel 36, the ionizing star of the HG region.

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