A Comprehensive Study of X-ray Emission Lines from Cataclysmic Variables

A comprehensive spectral study of a sample of 12 Cataclysmic Variables using high resolution X-ray data from the Chandra High Energy Transmission Grating is presented. The G-ratio value for the Fe XXV triplets suggests either coronal or photoionized conditions at 14 MK in U Gem, AO Psc, and one epoch of WX Hyi. For EX Hya it is either coronal plasma at temperatures < 1 MK or photoionized plasma at 14 MK that dominates the spectrum. The G-ratio for Si XIII provides a lower limit Of similar to 10(6) K for the electron temperature in all objects. SS Cyg and U Gem show significantly broadened emission lines during outburst compared to quiescence corresponding to a high velocity of similar to 2300 km s(-1). SS Cyg shows a flat-topped line profile for the Fe XXV line that is likely from outflowing wind. Significant broadening of flourescent Fe line is observed in V603 Aql during its quiescent state. The phase resolved spectroscopy of AM Her shows that the centers of the emission lines of Fe XXVI, S XVI, and the resonance fine of Fe XXV are shifted by a few hundred to 1000 km s(-1) from the theoretically expected values indicating bulk motion of ionized matter in the accretion column. Line intensifies of H-like ions are modulated by the binary period in EX Hya.