Photoionized Features in the X-ray Spectrum of EX Hydrae [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2009. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- PDF-file: 21 pages; size: 0.2 Mbytes
- Additional Creators:
- Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- We present the first results from a long (496 ks) Chandra High Energy Transmission Grating observation of the intermediate polar EX Hydrae. In addition to the narrow emission lines from the cooling post-shock gas, for the first time we have detected a broad component in some of the X-ray emission lines, namely O VIII λ18.97, Mg XII λ8.42, Si XIV λ6.18, and Fe XVII λ16.78. The broad and narrow components have widths of ≈ 1600 km s⁻¹ and ≈ 150 km s⁻¹, respectively. We also find that the flux of the broad component is modulated at the white dwarf spin period, constraining the region where the gas is formed. We propose a scenario where the broad component is formed in the pre-shock flow photoionized by radiation from the post-shock flow. Because the photoionized region has to be close to the radiation source in order to produce strong photoionized emission lines from ions like O VIII, Mg XII, and Si XIV, our photoionization model constrains the height of the standing shock above the white dwarf surface.
- Published through SciTech Connect., 09/28/2009., "llnl-jrnl-417591", Astrophysical Journal, vol. 711, no. 2, March 10, 2010, pp. 1333-1337 711 2 ISSN 0004-637X; ASJOAB FT, and Raymond, J C; Mauche, C W; Brickhouse, N S; Hoogerwerf, R; Luna, G M; Steeghs, D; Proga, D.
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