O VII 21.602, 21.804 Angstroms

Non-porous models

Note: We fit only the MEG data. There are 225 MEG counts in the spectral region we fit (and plot below). See the fitting log. We fit the resonance and intercombination lines; the forbidden line isn't detected.

Continuum fit on 21.2:21.4 and 22.0:22.2. For n=2, best-fit norm=1.87e-3. The 68% confidence limits on the normalization are +/- 4e-4. And the best fit is formally a good fit.

O VII 21.602, 21.804: non-porous MEG [21.42:22.00], λo = 21.602, 21.804
powerlaw continuum, n=2; norm=1.87e-3
taustar=1.62   +/- (0.83:2.95)
uo=0.395   +/- (0.296:0.493)
norm=3.19e-4, 2.80e-4 +/- (2.91e-4:3.59e-4), (2.42e-4:3.09e-4)
rejection probability = 37% (C=206.94; N=230)

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

O VII 21.602: joint uo taustar constraints using MEG data - standard plotting range

Note that the global best-fit is at a significantly lower value of uo than we find for most lines. We made a second version of the confidence limit contour plot, showing smaller values of uo:

O VII 21.602: joint uo taustar constraints using MEG data - lower uo plotting range

This is the same range we show in the confidence limit plot for the Ne VII Lyman alpha line.

Note that although values of uo < 0.5 (Ro > 2 R*) are mildly preferred, "standard" values of ~0.65 aren't even ruled out at the 90% confidence level.


Next, we fit isotropic porosity models to the data. And after that, anisotropic porosity models.


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last modified: 5 July 2008