Modelling absorption and emission profiles from accretion disc winds with WINE
Caption: An assessment of the detection capabilities of the Athena X-IFU microcalorimeter for photoionised absorbers. We simulated sets of 1000 spectra with 100 ks exposure of AGN warm absorbers. The input model consists of a featureless AGN continuum with an absorbing and emitting photoionised gas on top. From top to bottom and left to right, the panels report the accuracy Delta with which the gas ionisation, velocity, column density and covering factor (i.e, the opening angle of the emitting region) are retrieved, as a function of the opacity (i.e. the column density). Delta is the mean of
A. Luminari
Fast and massive ionised gas is ubiquitously observed in the UV and, especially, X-ray spectra of accreting sources. In both stellar- and supermassive-scale systems, such winds offer a unique window to characterise the closest accretion environment. In the case of Active Galactic Nuclei, winds are one of the main candidates to efficiently transfer the accretion-liberated energy up to the host galaxy scale and, thus, to establish the so-called feedback between the AGN and its galaxy. However, we still lack a clear picture of such intervening gas, due to both the limited signal-to-noise ratio of current observations and to the limitations of the available modelling tools.
In this paper we performed a thorough investigation of the (X-ray) spectral appearance of such winds through the Wind in the Ionised Nuclear Environment (WINE) spectral model. WINE performs a detailed modellisation of the absorption and emission features, accounting for both the physics (ionisation, column density) and the kinematics (velocity, geometry, radial location) of the gas. Such a precise diagnostic allows one to maximise the scientific output of X-ray observations, especially the high-resolution data from XRISM/Resolve and the upcoming XIFU microcalorimeter. By directly constraining the energetic of such winds, it will be possible to finally constrain their role in the AGN feedback, which is one of the open topic in high-energy astrophysics and one of the leading scientific aims of the Athena observatory.
We simulated ionised winds with WINE over a broad range of properties, encompassing the typical values observed for disc winds in AGNs. We demonstrated that XIFU will be able to significantly detect (in up to 100% of the cases through absorption) and characterise them, with enough accuracy to significantly derive the most fundamental properties such as its mass and energy outflow rates. We also released absorption and emission tables which can be used to either fit observed data and to assess the performances of present and upcoming instruments.
More information: https://baltig.infn.it/ionisation/wine