Unit 1
The first unit is the most general, in which the emission associated
to the X-ray emitting component (e.g. the ICM gas) in the hydrodynamical simulation is calculated,
based on a theoretical emission model.
To each emitting element it is then associated a package of ideal photons,
generated via a Monte-Carlo sampling of the spectral distribution.
This first unit has to be executed
independently from the others, just once per simulation output.
Unit 2
The second unit of the code takes into account the geometry of the forseen
observation, the observing time and the total ideal collecting area of the instrument
to be used. The projection along a given line of sight is applied and
photon energies are corrected for the Doppler Shift due to the l.o.s. velocity component
of the parent emitting element.
Unit 3
In the third unit, the detailed instrument properties are taken into account.
Here the convolution with the instrument response matrices is done.
This unit can be conveniently replaced by any desired X-ray
instrument simulator, like
XISSIM
for the Suzaku X-ray
Imaging Spectrometer,
MARX for Chandra, or
SIXTE,
designed to obtain mock observations for eROSITA, ATHENA or XMM-Newton.
ICM X-ray emission.
The spectral model assumed accounts for thermal (temperature, density) and
chemical (total metallicity or single chemical abundances)
properties of the emitting gas, which are computed in state-of-the-art hydro-simulations.
Gas velocities are naturally included and contribute to the non-thermal broadening of X-ray emission lines.
X-ray emission from AGNs.
Unit 1 has also been modified to account for X-ray emission
from AGN sources associated to BH elements in the simulation.
Biffi et al. 2018 (MNRAS 481, 2213)
X-ray emission from XRBs.
An additional emission module has been implemented into Unit 1 to model
X-ray emission from high-mass and low-mass X-ray binaries (XRBs) associted
to stellar elements in the simulations.
Vladutescu-Zopp, Biffi, Dolag 2022 (A&A, 669, A34)
