Six years of XMM-Newton observations of NGC 1313 X-1 and X-2

Abstract

We present a systematic analysis of the X-ray spectra of NGC 1313 X-1 and NGC 1313 X-2, using six years of XMM-Newton observations (17 observations). We fitted the continuum with a Comptonization model plus a multicolor blackbody disc, that describes the effects of an accretion disc plus an optically thick corona. We checked the consistency of this spectral model on the basis of the variability patterns of its spectral parameters. We found that the two sources show different spectral states. We tentatively interpret the observed behaviour of NGC 1313 X-1 within the framework of super-Eddington accretion and that of NGC 1313 X-2 within the framework of near Eddington accretion. We also attempted to determine the chemical abundances in the local environment of NGC 1313 X-1 and X-2, analyzing the RGS spectra of the longest observation available (122 ksec). The results appear to indicate solar metallicity for the local environment of NGC 1313 X-1 and sub-solar metallicity for NGC 1313 X-2.

5 pages, 6 figures. Accepted for publication in the Astronomische Nachrichten (Astronomical Notes), to appear in the proceedings of the conference "Ultra-Luminous X-ray sources and Middle Weight Black Holes" (Madrid, May 24-26, 2010)

References in corpus (9)

• XMM-Newton observations of the brightest Ultraluminous X-ray sources
• A 62 Day X-Ray Periodicity and an X-Ray Flare from the Ultraluminous X-Ray Source in M82
• Spectral State Transitions of the Ultraluminous X-ray Sources X-1 and X-2 in NGC 1313
• On the weakness of disc models in bright ULXs
• A survey of the Wolf-Rayet population of the barred, spiral galaxy NGC 1313
• X-ray spectral variability in the ultraluminous X-ray source Holmberg IX X-1
• Confirmation of the 62 Day X-Ray Periodicity from M82
• Discovery of a 115 Day Orbital Period in the Ultraluminous X-ray Source NGC 5408 X-1
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Cited by in corpus (4)

• X-ray spectral states and metallicity in the ultraluminous X-ray sources NGC 1313 X-1 and X-2
• X-ray spectroscopy in the microcalorimeter era 4: Optical depth effects on the soft X-rays studied with CLOUDY
• Investigating the nature of the ultraluminous X-ray sources in the galaxy NGC 925
• The largest bright ULX population in a galaxy: X-ray variability and Luminosity Function in the Cartwheel ring Galaxy