Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2003
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003mnras.346..704a&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Volume 346, Issue 3, pp. 704-718.
Astronomy and Astrophysics
Astronomy
26
H Ii Regions, Ism: Individual: Ngc 3372, X-Rays: Ism, X-Rays: Stars
Scientific paper
We use new XMM-Newton observations to perform a detailed X-ray analysis of the Carina nebula region in the 0.3-12 keV energy range. Our source detection yields 80 discrete X-ray sources, from which about 20 per cent seem not to have optical counterparts. To get an idea of the energy spectrum of these sources, we construct an X-ray colour-colour diagram using the energy bands 0.3-2, 2-4.5 and 4.5-12 keV. We analyse the spectra of the most intense X-ray sources associated with early-type stars, including the luminous blue variable η Carina and WR25. We show that the X-ray emission from these sources is well fitted by multitemperature model spectra. We detect surprisingly intense X-ray emission at energies above 4 keV for some of the observed early-type stars, especially from CPD-59 2629 (Tr16-22) which presents particularly hard X-ray emission. We detect intense soft X-ray emission, below <2 keV, in HDE 303311, which presents an X-ray excess of about 100 times higher than has been observed in other O5V stars. We use these data to construct the Lx/Lbol relation for the 0.3-12 and 3.0-12 keV energy ranges, for all the observed O-type stars, plus η Carina and WR25. Most of the bright stars seem to agree with low metallicity spectral models. The Lx/Lbol ratio for O-type stars in the 0.3-12 keV range is well fitted by a constant ~6.07.54.8× 10-7, in fair agreement with the canonical expression Lx/Lbol~ 2 × 10-7 formerly estimated for the 0.3-2.4 keV energy band. In contrast, the Lx/Lbol relation for the 3.0-12 keV range presents a strong deviation from the canonical relation, with a high dispersion of about four orders of magnitude. We also detect intrinsic X-ray time variability in seven sources, over the time-scale of about 50 h covered by the observations. This includes an X-ray flare of about 2-h duration detected in DETWC Tr16 J104429.2-594143, a source probably not physically associated with the Carina nebula. We discuss the different underlying physical mechanisms that can be responsible for the X-ray emission from early-type stars.
Albacete Colombo Juan Facundo
Méndez Mariano
Morrell Nidia I.
No associations
LandOfFree
XMM-Newton X-ray observations of the Carina nebula does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with XMM-Newton X-ray observations of the Carina nebula, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and XMM-Newton X-ray observations of the Carina nebula will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-883771