在高场磁变星 V884 Her 中暴露的涡旋基本面
摘要
Presented for the magnetic cataclysmic variable V884 Her are high-quality phase-resolved optical spectropolarimetry. During active accretion states, the overall circular polarization is low and only slightly variable in the range 5000-8000A. However, the polarization is highly structured with wavelength, showing very broad polarization humps, narrow features that are associated with weak absorption lines in the total spectral flux, and sharp reversals across each major emission line. The polarization reversals arise from Zeeman splitting in the funnel gas in a longitudinal magnetic field B~30kG. The set of narrow, polarized absorption features matches the Zeeman pattern of hydrogen for a nearly uniform magnetic field of B=150MG, indicating that the features are "halo" absorption lines formed in a relatively cool reversing layer above the shock. With this identification, the broad polarization humps centered near 7150A and below 4000A are assigned to cyclotron emission from the fundamental and first harmonic (n=2), respectively. V884 Her is only the second AM Her system known with a field exceeding 100MG, and the first case in which the cyclotron fundamental has been directly observed from a magnetic white dwarf.
引用
@article{arxiv.astro-ph/0012473,
title = {The Cyclotron Fundamental Exposed in the High-Field Magnetic Variable V884 Her},
author = {G. D. Schmidt and L. Ferrario and D. T. Wickramasinghe and P. S. Smith},
journal= {arXiv preprint arXiv:astro-ph/0012473},
year = {2009}
}
备注
14 pages, 6 figures, LaTeX, to appear in The Astrophysical Journal, Part 1