XMM-Newton Observation of the Intermediate Polar XY Ari
Abstract
XY Ari is a rare Intermediate Polar which shows deep X-ray eclipses and has no optical counterpart due to the high visual extinction. We present results from a detailed analysis of an unpublished archival observation using XMM-Newton EPIC-pn and MOS data covering to more than five orbital periods in a quiescent state of XY Ari. The X-ray orbital modulation and spin pulse variations were investigated in 0.2-10 keV energy band and also in different energy bands (i.e. 0.3-1.5, 1.6-3.0, 3.1-10 keV). The EPIC light curves folded at the spin phases show a double peak profile as expected from double pole accretion. However, a detailed analysis showed that the relative peak heights of the spin profiles, corresponding to different time intervals, vary during the entire observation which may be a result of small accretion rate differences or variable scattering from the weaker pole. We modeled the time-averaged spectrum with single- and multi-temperature optically thin thermal plasma emission (e.g. MEKAL APEC/VAPEC, CEVMKL, MKCFLOW/VMKCFLOW) in XSPEC to derive spectral parameters. The simultaneously fitted EPIC spectra with a double MEKALs model yield plasma temperatures of kT_{MEKAL}=39-44 keV and kT_{MEKAL}=0.3-2.21 keV with a solar metal abundance of 0.52-71 (for higher MEKAL temperature). We find an intrinsic, partial covering absorption about N _{H}=2.9-5.5x10 ^{22} cm ^{-2}. In addition, Gaussian lines at the Fe line energies 6.4 and 6.7 keV, were also included in the fit. We will discuss different model fits and the accretion geometry of the system. The X-ray luminosity of the source is ∼2x10 ^{32} erg/sec in the 0.2-10.0 keV range assuming a 270 pc distance.
- Publication:
-
41st COSPAR Scientific Assembly
- Pub Date:
- July 2016
- Bibcode:
- 2016cosp...41E2154Z