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arXiv · 1801.08508

Measuring the masses of Intermediate Polars with NuSTAR: V709 Cas, NY Lup and V1223 Sgr

A. W. Shaw·C. O. Heinke·K. Mukai·G. R. Sivakoff·J. A. Tomsick·V. Rana
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Abstract

The X-ray spectra of intermediate polars can be modelled to give a direct measurement of white dwarf mass. Here we fit accretion column models to NuSTAR spectra of three intermediate polars; V709 Cas, NY Lup and V1223 Sgr in order to determine their masses. From fits to 3-78 keV spectra, we find masses of $M_{\rm WD}=0.88^{+0.05}_{-0.04}M_{\odot}$, $1.16^{+0.04}_{-0.02}M_{\odot}$ and $0.75\pm0.02M_{\odot}$ for V709 Cas, NY Lup and V1223 Sgr, respectively. Our measurements are generally in agreement with those determined by previous surveys of intermediate polars, but with typically a factor $\sim2$ smaller uncertainties. This work paves the way for an approved NuSTAR Legacy Survey of white dwarf masses in intermediate polars.

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A. W. Shaw, C. O. Heinke, K. Mukai, G. R. Sivakoff, J. A. Tomsick, V. Rana. 2018-01-25. Measuring the masses of Intermediate Polars with NuSTAR: V709 Cas, NY Lup and V1223 Sgr. https://doi.org/10.1093/mnras/sty246

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