Accretion Column Structure of Magnetic Cataclysmic Variables from X-ray Spectroscopy

Journal Article · Mon Feb 27 04:00:00 EST 2006 · Astrophysical Journal, vol. 643, N/A, May 20, 2006, L45-L48

DOI:https://doi.org/10.1086/505029· OSTI ID:894753

Hoogerwerf, R; Brickhouse, N S; Mauche, C W

Using Chandra HETG data we present light curves for individual spectral lines of Mg XI and Mg XII for EX Hydrae, an intermediate-polar type cataclysmic variable. The Mg XI light curve, folded on the white dwarf spin period, shows two spikes that are not seen in the Mg XII or broad-band light curves. Occultation of the accretion column by the body of the white dwarf would produce such spikes for an angle between the rotation axis and the accretion columns of {alpha} = 18{sup o} and a height of the Mg XI emission above the white dwarf surface of {approx}< 0.0004 white dwarf radii or {approx}< 4 km. The absence of spikes in the Mg XII and broad-band light curves could then be explained if the bulk of its emission forms at much larger height, > 0.004 white dwarf radii or > 40 km, above the white dwarf surface. The technique described in this letter demonstrates that high signal-to-noise ratio and high spectral resolution X-ray spectra can be used to map the temperature and density structure of accretion flows in magnetic cataclysmic variables. The Mg XI and Mg XII light curves are not consistent with the temperature and density structure predicted by the standard Aizu model.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 894753
• Report Number(s): UCRL-JRNL-220483
• Journal Information: Astrophysical Journal, vol. 643, N/A, May 20, 2006, L45-L48, Journal Name: Astrophysical Journal, vol. 643, N/A, May 20, 2006, L45-L48
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
RESOLUTION
ROTATION
SIGNAL-TO-NOISE RATIO
SPIN
X-RAY SPECTRA
X-RAY SPECTROSCOPY