We model phase-resolved spectra of the polar MQ Dra with both a constant-lambda prescription as well as with a structured shock code built by Fischer & Beuermann (2001). In each case, the observed spectra are well fit with a shock of B similar or equal to 59 MG and kT(max) similar or equal to 1.5 keV, However, the orbital morphology of the cyclotron spectra cannot be explained with a simple geometry (constant inclination, i, and magnetic co-latitude, beta), as the implied cyclotron maximum of such models occur at apparent photometric minimum. We explain this anomaly as an effect of foreshortening of the accretion region. However, the foreshortening curves can only work for geometries in which the local field line angle ("b") to the emission region is continuously variable throughout the orbit.
机构:
New Mexico State Univ, Dept Astron, POB 30001,MSC 4500, Las Cruces, NM 88003 USANew Mexico State Univ, Dept Astron, POB 30001,MSC 4500, Las Cruces, NM 88003 USA
Harrison, Thomas E.
Campbell, Ryan K.
论文数: 0引用数: 0
h-index: 0
机构:
Humboldt State Univ, Dept Phys & Astron, 1 Harpst St, Arcata, CA 95521 USANew Mexico State Univ, Dept Astron, POB 30001,MSC 4500, Las Cruces, NM 88003 USA