4.1.19. Hyd: model with user-own hydrodynamical simulationΒΆ

This model calculates the spectrum of a plasma with a given set of ion concentrations. It allows users to calculate the X-ray spectrum corresponding to his own hydrodynamical simulation results. The basic usage is that the user first runs own calculations to obtain the ion concentrations, and stores them in an ascii file. The name should be either of spexicon_abs.dat or spexicon_rel.dat. Then the user runs SPEX and loads the Hyd model to calculate the spectrum.

For users who are familiar with Fortran, we offer the supporting fortran90 subroutine, hydro_driver, to make the ion concentration file conveniently. The usage of the hydro_driver is described in Hydro driver.

For more general cases users can directly load the Hyd model and just calculate the spectrum. The model has two modes to specify the format for the ion concentrations: absolute (mode 1) or relative (mode 2). For mode 1, the input file must have the name spexicon_abs.dat, and the values are treated as absolute ion concentrations (relative to hydrogen). In this mode the parameters of the elemental abundances do not affect the ion concentration nor the spectrum at all (they are ignored). For the case that users wish to treat elemental abundances as fitting parameters, mode=2 can be used. In this mode the input file must have the name spexicon_rel.dat, which contains the ion concentrations relative to the concentration of the relevant chemical element.

The parameters of the model are:

hyd : Hydrogen density in 10^{20} \mathrm{m}^{-3}
mode : Mode of the model. Mode=1: read absolute ion concentration from spexicon_abs.dat. mode=2: read relative ion concentration from spexicon_rel.dat.

The following parameters are the same as for the cie-model:

norm : the normalisation, which is the emission measure Y \equiv  n_{\mathrm e} n_{\mathrm H} V in units of 10^{64} \mathrm{m}^{-3}, where n_{\mathrm e} and n_{\mathrm H} are the electron and Hydrogen densities and V the volume of the source. Default value: 1.
t : the electron temperature T_{\mathrm e} in keV. Default value: 1.
it : Ion temperature in keV.
vrms : RMS Velocity broadening in km/s (see Definition of the micro-turbulent velocity in SPEX).
ref : Reference element.
01...30 : Abundances of H to Zn.
file : Filename for the non-thermal electron distribution.


By default, SPEX starts with var calc old (see the var menu for explanation). If you want to use this model with the latest atomic database, you should set the ionisation balance to U17. Note that this is only used to calculate inner-shell ionisation rates for the spectral evaluation, it will not affect the ion concentrations that the user provides.

Recommended citation (first use): Kosenko et al. (2015).