# Emission lines

## Analysis of the entire 94 ks observation

Note that "+/-" uncertainties are actually 68% confidence ranges for the specified parameters.

### Si XIV Lyα

We use an emissivity-weighted mean wavelength of 6.1822 A for the Lyman-alpha doublet of H-like silicon. We fit the MEG (top) and HEG (bottom) with *wgauss + pow*:

### Si XIII Heα

He-like complexes - resonance, intercombination, forbidden lines - in the MEG (top) and HEG (bottom) panels, fit with *hegauss + pow*:

### S XVI Lyα

We use an emissivity-weighted mean wavelength of 4.731 A for the Lyman-alpha doublet of H-like sulfur. We fit the MEG (top) and HEG (bottom) with *wgauss + pow*:

### S XV Heα

He-like complexes - resonance, intercombination, forbidden lines - in the MEG (top) and HEG (bottom) panels, fit with *hegauss + pow*:

### Summary of line ratios

Si XIV/XIII = 1.50^{+.33}_{-.28}

Si XIII R = f/i = 5.40_{-2.2} while R_{o}=2.3

S XVI/XV = 0.55^{+.26}_{-.18}

S XV R = f/i = 1.90^{+2.28}_{-.82} while R_{o}=2.0

These ratios can be compared to models (temperature for Lyα/Heα and density for R = f/i). And we could also divide up the data into pre-flare, flare, and post-flare intervals and look for statistically significant changes in the line ratios. Thus far, we have only done this for the Fe K-shell lines seen in the HEG spectrum:

### Line ratio modeling: *R* values for the He-like features

Both the Si XIII and the S XV *R=f/i* are consistent with the low-density limit. Because the Si XIII *f/i* ratio has the lower critical density, this feature provides the stronger constraint of the two.

Si XIII: 95% lower confidence bound on *f/i* is shown as a dash-dotted line, corresponding to a range of densities (4 to 9 X 10^{12} cm^{-3}), depending on the choice of model (solid is Blumenthal, Drake, & Tucker 1972; dotted is Porquet & Dubau 2001; and dashed is PrismSpect (MacFarlane et al., 2004)).

S XV: best-fit *f/i* is shown as the solid horizontal line. The 68% lower confidence bound is shown as the dotted line.

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*last modified*: 3 May 2009