1. A 500 ks Chandra/HETG observation of EX Hya Gerardo J. M. Luna (SAO)‏ Nancy Brickhouse (SAO)‏ John Raymond (SAO)‏ Chris Mauche (LLNL)‏ Daniel Proga (UNLV)‏ Danny Steeghs (University of Warwick)‏ Tucson, 2009

2. EX Hya - X-rays observations : 50 ks Chandra/HETG in 2000 Tucson, 2009 Cooling-flow spectrum non-magnetic CVs, except EX Hya Photoionized spectrum Magnetic CVs Mukai et al (2003)‏

3. Comparison with Capella Calibration uncertainty? Chandra Line Profile Function? EX Hya line profiles Tucson, 2009

4. EX Hya line profiles Tucson, 2009 Si XIII Fe XVII Mg XIIFe XVII

5. EX Hya lines density diagnostic We measure the density using 3 different line ratios (f/i), Fe XXII, Fe XVII and Si XIII. The values agree with previous measurements (Mauche et al 2005). Tucson, 2009

6. EX Hya line-based light curves Tucson, 2009

7. EX Hya line-based light curves Allan et al. (1998) Tall shock, ~ 1R WD

8. EX Hya line-based light curves

9. Photoionization model We assume a dipole field and the density just above the shock as a parameter, n 0 =n 14 10 14 cm -3 As n 0 goes from 1 to 10, the area of the accretion spot goes from 0.143-0.045 R WD and the height of the shock goes from 0.459 to 0.046 R WD. For scales near the accretion spot size, the dilution factor of the X-ray radiation drops rapidly as (r spot /(r-1)) 2. The ionization parameters drops quickly close to the accretion spot. For large height it drops as r -2 and the ionization parameter rise slowly as r 1/2. Tucson, 2009

10. Photoionization model Tucson, 2009 α φ

11. Photoionization model Add compressional heating Escape probabilities and collisional quenching Continuum radiative transfer along the column Line radiative transfer along the column Accurate Hα and UV fluxes. Tucson, 2009

12. Shock model Commonly modeled as a cooling-flow model with EMαT β, where β=1/2 for T>10 7 and β=3/2 for T<10 7 (e.x. Hoogerwerf et al. 2006). Tucson, 2009

13. Synthesis A long exposure in X-rays has allowed us to observe for the first time new features in the accretion column of EX Hya. High signal-to-noise line profiles revealed a photoionization component with FWHM~1600 km/s. Preliminary photoionization models show that OVIII, Si XIV, Mg XII are formed close to the shock, and this is confirmed by their modulation at the spin period. We measure more accurately density diagnostic lines ratios with the unprecedented quality of this dataset. Tucson, 2009