1945 20160701171655.0 10.1051/0004-6361:20021230 DOI ASTROimport-102 Rauw, G. 2002 An XMM-Newton observation of the Lagoon Nebula and the very young open cluster NGC 6530 We report the results of an XMM-Newton observation of the Lagoon Nebula (M 8). Our EPIC images of this region reveal a cluster of point sources, most of which have optical counterparts inside the very young open cluster NGC 6530. The bulk of these X-ray sources are probably associated with low and intermediate mass pre-main sequence stars. One of the sources experienced a flare-like increase of its X-ray flux making it the second brightest source in M 8 after the O4 star 9 Sgr. The X-ray spectra of most of the brightest sources can be fitted with thermal plasma models with temperatures of kT ~ a few keV. Only a few of the X-ray selected PMS candidates are known to display Ha emission and were previously classified as classical T Tauri stars. This suggests that most of the X-ray emitting PMS stars in NGC 6530 are weak-line T Tauri stars. In addition to 9 Sgr, our EPIC field of view contains also a few early-type stars. The X-ray emission from HD 164816 is found to be typical for an O9.5 III-IV star. At least one of the known Herbig Be stars in NGC 6530 (LkHa 115) exhibits a relatively strong X-ray emission, while most of the main sequence stars of spectral type B1 and later are not detected. 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 Hourglass Region. Based on observations with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member states and the USA (NASA). Nazé, Y. Gosset, E. Stevens, I. R. Blomme, R. Corcoran, M. F. Pittard, J. M. Runacres, M. C. Astronomy and Astrophysics 395 2002 499-513 http://esoads.eso.org/abs/2002A%26A...395..499R published in REFERD