Accretion Geometry in the Hard State of the Black-Hole X-Ray Binary MAXI J1820+070. (arXiv:2101.04482v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Zdziarski_A/0/1/0/all/0/1">Andrzej A. Zdziarski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dzielak_M/0/1/0/all/0/1">Marta A. Dzielak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marco_B/0/1/0/all/0/1">Barbara De Marco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Szanecki_M/0/1/0/all/0/1">Michal Szanecki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Niedzwiecki_A/0/1/0/all/0/1">Andrzej Niedzwiecki</a>
We study X-ray spectra from the outburst rise of the accreting black-hole
binary MAXI J1820+070. We find that models having the disk inclinations within
those of either the binary or the jet imply significant changes of the
accretion disk inner radius during the luminous part of the hard spectral
state, with that radius changing from $>$100 to $sim$10 gravitational radii.
The main trend is a decrease with the decreasing spectral hardness. Our
analysis requires the accretion flow to be structured, with at least two
components with different spectral slopes. The harder component dominates the
bolometric luminosity and produces strong, narrow, X-ray reflection features.
The softer component is responsible for the underlying broader reflection
features. The data are compatible with the harder component having a large
scale height, located downstream the disk truncation radius, and reflecting
mostly from remote parts of the disk. The softer component forms a corona above
the disk up to some transition radius. Our findings can explain the changes of
the characteristic variability time scales, found in other works, being driven
by the changes of the disk characteristic radii.
We study X-ray spectra from the outburst rise of the accreting black-hole
binary MAXI J1820+070. We find that models having the disk inclinations within
those of either the binary or the jet imply significant changes of the
accretion disk inner radius during the luminous part of the hard spectral
state, with that radius changing from $>$100 to $sim$10 gravitational radii.
The main trend is a decrease with the decreasing spectral hardness. Our
analysis requires the accretion flow to be structured, with at least two
components with different spectral slopes. The harder component dominates the
bolometric luminosity and produces strong, narrow, X-ray reflection features.
The softer component is responsible for the underlying broader reflection
features. The data are compatible with the harder component having a large
scale height, located downstream the disk truncation radius, and reflecting
mostly from remote parts of the disk. The softer component forms a corona above
the disk up to some transition radius. Our findings can explain the changes of
the characteristic variability time scales, found in other works, being driven
by the changes of the disk characteristic radii.
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