I. Nasiroglu, A. Słowikowska, G. Kanbach, F. Haberl
We present fast timing photometric observations of the intermediate polar
V2069 Cygni (RX J2123.7+4217) using the Optical Timing Analyzer (OPTIMA) at the
1.3 m telescope of Skinakas Observatory. The optical (450-950 nm) light curve
of V2069 Cygni was measured with sub-second resolution for the first time
during July 2009 and revealed a double-peaked pulsation with a period of 743.38
+0.25. A similar double-peaked modulation was found in the simultaneous Swift
satellite observations. We suggest that this period represents the spin of the
white dwarf accretor. Moreover, we present the results from a detailed analysis
of the XMM-Newton observation that also shows a double-peaked modulation,
however shifted in phase, with 742.35 +0.23 s period. The X-ray spectra
obtained from the XMM-Newton EPIC (European Photon Imaging Camera) instruments
were modelled by a plasma emission and a soft black body component with a
partial covering photo-electric absorption model with covering fraction of
0.65. An additional Gaussian emission line at 6.385 keV with an equivalent
width of 243 eV is required to account for fluorescent emission from neutral
iron. The iron fluorescence (~6.4 keV) and FeXXVI lines (~6.95 keV) are clearly
resolved in the EPIC spectra. In the Porb-Pspin diagram of IPs, V2069 Cyg shows
a low spin to orbit ratio of ~0.0276 in comparison with ~0.1 for other
intermediate polars.
View original:
http://arxiv.org/abs/1201.5629
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