Fe XVII 15.014 Angstroms

Models with anisotropic porosity

Note: Both MEG and HEG are being fit simultaneously

Same continuum fit as we used for the non-porous and isoporous models: n=2, best-fit norm=1.71e-3.

Note that the opacity bridging law used for these isoporosity fits is Rosseland.

[14.87:15.13]
v_inf=2250
β=1
powerlaw continuum, n=2; norm=1.71e-3
q=0
h_inf=0.00 +/- (0.00:0.04) and for 90%
confidence, (0.00:0.10)
taustar=1.90 +/- (1.62:2.26)
u_o=0.643 +/- (0.596:0.701)
norm=5.27e-4 +/- (5.07e-4:5.48e-4)
rejection probability = 27% (C=280.81; N=308)

Note that the above parameters don't agree exactly with those from the baseline (non-porous) fit, despite the fact that the above model has h_inf=0. The parameter values are very close, though. The slight difference is just a result of the relative flatness of the fit statistic in the portion of parameter space surrounding the global minimum.

Here are the 68%, 90%, and 95% joint confidence limits on h_inf and taustar. The asterisk represents the best-fit model, shown as the red histograms on the above two plots.

Models with anisotropic porosity provide such a bad fit, that even modest values of the porosity length are ruled out. And consequently, allowing a non-zero porosity length does not affect the confidence contours in taustar-u_o parameter space. So we do not show a new version of that plot here.

Forcing a fit with taustar=8, the value implied by the literature mass-loss rate:

[14.87:15.13]
v_inf=2250
β=1
powerlaw continuum, n=2; norm=1.71e-3
q=0
h_inf=1.59 +/- (1.26:2.04) and for 90%
confidence, (1.07:2.42)
taustar=8
u_o=0.663 +/- (0.620:0.715)
norm=5.28e-4 +/- (5.08e-4:5.48e-4)
rejection probability = 84% (C=322.37; N=308)

Note that ΔC=42 (compared to the global best-fit model, which has zero porosity length), highly ruling out this model.

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last modified: 28 April 2008