Observing the simulations: Applying ZDI to 3D non-potential magnetic field simulations. (arXiv:1811.03703v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Lehmann_L/0/1/0/all/0/1">L. T. Lehmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hussain_G/0/1/0/all/0/1">G. A. J. Hussain</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jardine_M/0/1/0/all/0/1">M. M. Jardine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mackay_D/0/1/0/all/0/1">D. H. Mackay</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vidotto_A/0/1/0/all/0/1">A. A. Vidotto</a>
The large-scale magnetic fields of stars can be obtained with the
Zeeman-Doppler-Imaging (ZDI) technique, but their interpretation is still
challenging as the contribution of the small-scale field or the reliability of
the reconstructed field properties is still not fully understood. To quantify
this, we use 3D non-potential magnetic field simulations for slowly rotating
solar-like stars as inputs to test the capabilities of ZDI. These simulations
are based on a flux transport model connected to a non-potential coronal
evolution model using the observed solar flux emergence pattern. We first
compare four field prescriptions regarding their reconstruction capabilities
and investigate the influence of the spatial resolution of the input maps on
the corresponding circularly polarised profiles. We then generate circularly
polarised spectra based on our high resolution simulations of three stellar
models with different activity levels, and reconstruct their large-scale
magnetic fields using a non-potential ZDI code assuming two different stellar
inclination angles. Our results show that the ZDI technique reconstructs the
main features of slowly rotating solar-like stars but with $sim,$one order of
magnitude less magnetic energy. The large-scale field morphologies are
recovered up to harmonic modes $ell sim 5$, especially after averaging over
several maps for each stellar model. While ZDI is not able to reproduce the
input magnetic energy distributions across individual harmonic modes, the
fractional energies across the modes are generally within $20,%$ agreement.
The fraction of axisymmetric and toroidal field tends to be overestimated for
stars with solar flux emergence patterns for more pole-on inclination angles.
The large-scale magnetic fields of stars can be obtained with the
Zeeman-Doppler-Imaging (ZDI) technique, but their interpretation is still
challenging as the contribution of the small-scale field or the reliability of
the reconstructed field properties is still not fully understood. To quantify
this, we use 3D non-potential magnetic field simulations for slowly rotating
solar-like stars as inputs to test the capabilities of ZDI. These simulations
are based on a flux transport model connected to a non-potential coronal
evolution model using the observed solar flux emergence pattern. We first
compare four field prescriptions regarding their reconstruction capabilities
and investigate the influence of the spatial resolution of the input maps on
the corresponding circularly polarised profiles. We then generate circularly
polarised spectra based on our high resolution simulations of three stellar
models with different activity levels, and reconstruct their large-scale
magnetic fields using a non-potential ZDI code assuming two different stellar
inclination angles. Our results show that the ZDI technique reconstructs the
main features of slowly rotating solar-like stars but with $sim,$one order of
magnitude less magnetic energy. The large-scale field morphologies are
recovered up to harmonic modes $ell sim 5$, especially after averaging over
several maps for each stellar model. While ZDI is not able to reproduce the
input magnetic energy distributions across individual harmonic modes, the
fractional energies across the modes are generally within $20,%$ agreement.
The fraction of axisymmetric and toroidal field tends to be overestimated for
stars with solar flux emergence patterns for more pole-on inclination angles.
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