* Astronomy

Title: XMM-Newton EPIC and OM observation of Nova Centauri 1986 (V842 Cen)
Authors: G. J. M. Luna (IAFE/Conicet), M. P. Diaz (IAG), N. S. Brickhouse (CfA), M. Moraes (IAG)

We report the results from the temporal and spectral analysis of an XMM-Newton observation of Nova Centauri 1986 (V842 Cen). We detect a period at 3.51±0.4 h in the EPIC data and at 4.0±0.8 h in the OM data. The X-ray spectrum is consistent with the emission from an absorbed thin thermal plasma with a temperature distribution given by an isobaric cooling flow. The maximum temperature of the cooling flow model is kT_{max}=43_{-12}^{+23} keV. Such a high temperature can be reached in a shocked region and, given the periodicity detected, most likely arises in a magnetically-channelled accretion flow characteristic of intermediate polars. The pulsed fraction of the 3.51 h modulation decreases with energy as observed in the X-ray light curves of magnetic CVs, possibly due either to occultation of the accretion column by the white dwarf body or phase-dependent to absorption. We do not find the 57 s white dwarf spin period, with a pulse amplitude of 4 mmag, reported by Woudt et al. (2009) either in the Optical Monitor (OM) data, which are sensitive to pulse amplitudes \gtrsim 0.03 magnitudes, or the EPIC data, sensitive to pulse fractions p \gtrsim 14 ±2%.

Read more (174kb, PDF)