4.1.5. Cf: isobaric cooling flow differential emission measure model¶
This model calculates the spectrum of a standard isobaric cooling flow.
The differential emission measure distribution
for the isobaric cooling flow model can be
written as
where is the mass deposition rate,
is
Boltzmann’s constant,
the mean molecular weight (0.618 for a
plasma with 0.5 times solar abundances),
is the mass
of a hydrogen atom, and
is the cooling function. We
have calculated the cooling function
using our own
SPEX code for a grid of temperatures and for 0.5 times solar abundances.
The spectrum is evaluated by integrating the above differential emission
measure distribution between a lower temperature boundary
and a high temperature boundary
. We do this by creating a
temperature grid with
bins and calculating the spectrum for
each temperature.
Warning
Take care that is not too small in case the
relevant temperature is large; on the other hand if
is large,
the computational time increases. Usually a spacing with temperature
differences between adjacent bins of 0.1 (in
) is sufficient
and optimal.
Warning
The physical relevance of this model is a matter of debate.
The parameters of the model are:
- norm:
The mass deposition rate
in
.
- t1:
Lower temperature cut-off temperature
. Default: 0.1 keV.
- tn:
Upper temperature cut-off temperature
. Default: 1 keV.
- nr:
Number of temperature bins
used in the integration. Default value: 16
- p:
Slope
. Default: 0.25 (
).
- cut:
Lower temperature cut-off, in units of
. Default value: 0.1.
The following parameters are the same as for the cie-model:
- hden:
Hydrogen density in
.
- 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 nonthermal electron distribution
Recommended citation: Kaastra et al. (2004) and Fabian et al. (1984).