Modeling bias in supermassive black hole spin measurements. (arXiv:1911.06605v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Riaz_S/0/1/0/all/0/1">Shafqat Riaz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ayzenberg_D/0/1/0/all/0/1">Dimitry Ayzenberg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bambi_C/0/1/0/all/0/1">Cosimo Bambi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nampalliwar_S/0/1/0/all/0/1">Sourabh Nampalliwar</a>
X-ray reflection spectroscopy (or iron line method) is a powerful tool to
probe the strong gravity region of black holes, and currently is the only
technique for measuring the spin of supermassive black holes. While all the
available relativistic reflection models assume thin accretion disks, we know
that several sources accrete near or above the Eddington limit and therefore
must have thick accretion disks. In this Letter, we estimate the systematic
error on the spin measurement when a source with a thick accretion disk is
fitted with a thin disk model. Our results clearly show that the spin can be
significantly overestimated. Current spin measurements of sources with high
mass accretion rate are therefore not reliable.
X-ray reflection spectroscopy (or iron line method) is a powerful tool to
probe the strong gravity region of black holes, and currently is the only
technique for measuring the spin of supermassive black holes. While all the
available relativistic reflection models assume thin accretion disks, we know
that several sources accrete near or above the Eddington limit and therefore
must have thick accretion disks. In this Letter, we estimate the systematic
error on the spin measurement when a source with a thick accretion disk is
fitted with a thin disk model. Our results clearly show that the spin can be
significantly overestimated. Current spin measurements of sources with high
mass accretion rate are therefore not reliable.
http://arxiv.org/icons/sfx.gif
