A XMM-Newton observation of Nova LMC 1995, a bright supersoft X-ray source

Abstract

Nova LMC 1995, previously detected during 1995-1998 with ROSAT, was observed again as a luminous supersoft X-ray source with XMM-Newton in December of 2000. This nova offers the possibility to observe the spectrum of a hot white dwarf, burning hydrogen in a shell and not obscured by a wind or by nebular emission like in other supersoft X-ray sources. Notwithstanding uncertainties in the calibration of the EPIC instruments at E<0.5 keV, using atmospheric models in Local Thermonuclear Equilibrium we derived T(eff)=400,000-450,000 K, L(bol)=2.3 x 110(-14) 0(37) erg cm(-2) s(-1) and we verified that the C abundance is not significantly enhanced. The RGS spectra do not show emission lines of a wind or nebula, but the white dwarf absorption lines cannot be resolved. The upper limit to the flux in the 0.6-10 keV range is 10(-14) erg cm(-2) s(-1). There is no rapid or large variability in the light curve, but we find a peak at 5.25 hours in the power spectrum.