Hi,
I've been unable to get the xsmekal model to fit data within Sherpa. A
NAN is produced that halts (freezes) the process.
I'm using CIAO 2.01, Linux i686.
For example, the sherpa script:
data L.pi
ignore energy :0.5, 9:
subtract
# The emission model.
xsmekal[p1]
p1.kT = 10.0
p1.nH = 1e-5
p1.Abund = 0.2
p1.Redshift = 0.05
p1.Switch = 0
p1.norm = 1e-3
thaw p1.kT
thaw p1.norm
freeze p1.nH
freeze p1.Abund
freeze p1.Redshift
freeze p1.Switch
# The source model.
source = p1
statistic chi gehrels
method powell
fit
Produces the output:
The inferred file type is PHA. If this is not what you want, please
specify the type explicitly in the data command.
Background data are being input from:
L_bg.pi
RMF is being input from:
L.rmf
ARF is being input from:
L.arf
powll: v1.2
powll: initial function value = NAN
Which hangs (^C interupts)
While the same thing, but using a Raymond-Smith model, manages to fit
the data. As is shown
by the following script and output:
data L.pi
ignore energy :0.5, 9:
subtract
# The emission model. Raymond-Smith
xsraymond[p1]
p1.Abundanc = 0.2
p1.Redshift = 0.05
thaw p1.kT
thaw p1. norm
freeze p1.Abundanc
freeze p1.Redshift
# The source model.
source = p1
statistic chi gehrels
method powell
fit
Output:
The inferred file type is PHA. If this is not what you want, please
specify the type explicitly in the data command.
Background data are being input from:
L_bg.pi
RMF is being input from:
L.rmf
ARF is being input from:
L.arf
powll: v1.2
powll: initial function value = 6.16132E+03
powll: converged to minimum = 3.88723E+02 at iteration = 5
powll: final function value = 3.88723E+02
p1.kT 12.3582 keV
p1.norm 0.00467887 10**-14 / (4 pi D**2) Int n_e n_H dV
Any ideas as to what I'm doing wrong?
-- Dr. Eric Tittley Post Doctoral Research Associate Joint Center for Astrophysics UMBC
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