I've taken the ISO 7 and 15 micron maps for N6946, and used my SED models, to predict the surface brightness at IRS LL wavelengths.  
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The first plot displays the (S/N) spectra from the 11x79 different 4.8" pixels that lie within the 1'x6.4' IRS SED strip (see example <a href=S_N.image.gif>image </a>at 27.0 microns).  The largest-valued spectra come from the nucleus, whereas the weakest spectra represent the fainter disk.<pre></pre>

The second plot displays the (S/N) spectra you would get if binning was carried out 2x2 spatially, and collapsing spectrally by combining five spectral elements into one (see example <a href=S_N_binned.image.gif>image </a>at 28.0 microns).  The lines represent spectra from 5x39 different 9.6" pixels that lie with the strip.
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I am assuming the pre-flight sensitivity is applicable (<a href=http://physics.uwyo.edu/~ddale/research/sirtf/irs_simulation/noise.jpg>1sigma sensitivity</a>).

<pre><a href="S_N.ps">Plot of S/N for raw N6946 spectra</a> </pre>
<pre><a href="S_N_binned.ps">Plot of binned S/N for raw N6946 spectra</a> </pre>

Last updated 05 Jan 2004