A new emulated Monte Carlo radiative transfer disc-wind model: X-Ray Accretion Disc-wind Emulator xrade

0561051 - ASÚ 2023 RIV GB eng J - Journal Article
Matzeu, G. A. - Lieu, M. - Costa, M. T. - Reeves, J.N. - Braito, V. - Dadina, M. - Nardini, E. - Boorman, Peter G. - Parker, M. L. - Sim, S. A. - Barret, D. - Kammoun, E. - Middei, R. - Giustini, M. - Brusa, M. - Perez Cabrera, J. - Marchesi, S.
A new emulated Monte Carlo radiative transfer disc-wind model: X-Ray Accretion Disc-wind Emulator xrade.
Monthly Notices of the Royal Astronomical Society. Roč. 515, č. 4 (2022), s. 6172-6190. ISSN 0035-8711. E-ISSN 1365-2966
R&D Projects: GA ČR(CZ) GA22-22643S
Institutional support: RVO:67985815
Keywords : radiative transfer * numerical methods * spectroscopic techniques
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 4.8, year: 2022
Method of publishing: Limited access
https://doi.org/10.1093/mnras/stac2155

We present a new X-Ray Accretion Disc-wind Emulator (xrade) based on the 2.5D Monte Carlo radiative transfer code that provides a physically motivated, self-consistent treatment of both absorption and emission from a disc wind by computing the local ionization state and velocity field within the flow. xrade is then implemented through a process that combines X-ray tracing with supervised machine learning. We develop a novel emulation method consisting in training, validating, and testing the simulated disc-wind spectra into a purposely built artificial neural network. The trained emulator can generate a single synthetic spectrum for a particular parameter set in a fraction of a second, in contrast to the few hours required by a standard Monte Carlo radiative transfer pipeline. The emulator does not suffer from interpolation issues with multidimensional spaces that are typically faced by traditional X-ray fitting packages such as xspec. xrade will be suitable to a wide number of sources across the black hole mass, ionizing luminosity, and accretion rate scales. As an example, we demonstrate the applicability of xrade to the physical interpretation of the X-ray spectra of the bright quasar PDS 456, which hosts the best-established accretion disc wind observed to date. We anticipate that our emulation method will be an indispensable tool for the development of high-resolution theoretical models, with the necessary flexibility to be optimized for the next generation microcalorimeters onboard future missions, like X-Ray Imaging and Spectroscopy Mission (XRISM)/Resolve and Athena/X-ray Integral Field Unit (X-IFU). This tool can also be implemented across a wide variety of X-ray spectral models and beyond.
Permanent Link: https://hdl.handle.net/11104/0334232