X-Ray Observations of an Intermediate Polar V2400 Oph

Abstract

Abstract Based on the X-ray observations from XMM-Newton and Suzaku satellites at four different epochs, we present temporal and spectral properties of an intermediate polar (IP) V2400 Oph (=RX J1712.6-2414). The X-ray variations are found to occur at the spin and synodic periods and are derived to be 929 s and 1003 s, respectively. The X-ray spectrum is strongly absorbed by a dense material with an average equivalent hydrogen column density of ∼5 × 1022 cm−2, which partially covers ∼46% of the X-ray source. Suzaku spectra in the 0.3–50 keV energy range are well explained by two temperature collisional equilibrium plasma emission models with its reflection from the cold matter. A soft X-ray emission is also seen in the X-ray spectrum of V2400 Oph and is well modeled by the blackbody with an average temperature of ∼98 eV. The partial covering absorbers and softness ratio are spin phase dependent indicating that the coverage of accretion curtains is variable. A strong emission line of fluorescent Fe Kα at 6.4 keV is also detected in the X-ray spectra. The central energy of Fe Kα appears to be redshifted and found to be modulated with the white dwarf (WD) rotation, where modulations are at minimum around the spin minimum, indicating that the redshifted line is originated from pre-shock accreting material via fluorescence. An attempt is also made to characterize the system and to understand the magnetic accretion flows using the present data of V2400 Oph.