An XMM-Newton view of the M 17 nebula

• Published in: New astronomy Vol. 20; pp. 42 - 51
• Main Authors: Mernier, F., Rauw, G.
• Format: Journal Article Web Resource
• Language: English
• Published: Elsevier B.V 01-04-2013; Elsevier
• Subjects: Aérospatiale, astronomie & astrophysique; ISM: individual objects: M 17; Physical, chemical, mathematical & earth Sciences; Physique, chimie, mathématiques & sciences de la terre; Space science, astronomy & astrophysics; Stars: early-type; X-rays: stars; ISM: individual objects: M 17; Stars: early-type; X-rays: stars
• ISSN: 1384-1076; 1384-1092; 1384-1092
• DOI: 10.1016/j.newast.2012.09.005

► We present the analysis of an XMM observation of the M17 nebula. ► The two X-ray brighets O-stars display hard spectra (kT of 3.8 and 2.6keV) indicating a colliding wind origin. ► The strong interstellar reddening towards the O-type stars leads to huge uncertainties on their Lx/Lbol values. ► Low-mass pre-main sequence stars exhibit considerable long term (months to years) variability. ► There is little correspondence between UV and X-ray sources in the M17 field of view.
We present the analysis of an XMM-Newton observation of the M 17 nebula. The X-ray point source population consists of massive O-type stars and a population of probable low-mass pre-main sequence stars. CEN 1a,b and OI 352, the X-ray brightest O-type stars in M 17, display hard spectra (kT of 3.8 and 2.6keV) consistent with a colliding wind origin in binary/multiple systems. We show that the strong interstellar reddening towards the O-type stars of M 17 yields huge uncertainties on their LX/Lbol values. The low-mass pre-main sequence stars exhibit hard spectra resulting from a combination of high plasma temperatures and very large interstellar absorption. We find evidence for considerable long term (months to years) variability of these sources. M 17 is one of the few star formation complexes in our Galaxy producing diffuse X-ray emission. We analyze the spectrum of this emission and compare it with previous studies. Finally, we discuss the Optical Monitor UV data obtained simultaneously with the X-ray images. We find very little correspondence between the UV and X-ray sources, indicating that the majority of the UV sources are foreground stars, whilst the bulk of the X-ray sources are deeply embedded in the M 17 complex.