The first high resolution Spitzer IRS 9-37 \mu m spectra of 29 Seyfert galaxies ( about one quarter ) of the 12 \mu m Active Galaxy Sample are presented and discussed .
The high resolution spectroscopy was obtained with corresponding off-source observations .
This allows excellent background subtraction , so that the continuum levels and strengths of weak emission lines are accurately measured .
The result is several new combinations of emission line ratios , line/continuum and continuum/continuum ratios that turn out to be effective diagnostics of the strength of the AGN component in the IR emission of these galaxies .
The line ratios [ NeV ] / [ NeII ] , [ OIV ] / [ NeII ] , already known , but also [ NeIII ] / [ NeII ] and [ NeV ] / [ SiII ] can all be effectively used to measure the dominance of the AGN .
We extend the analysis , already done using the 6.2 \mu m PAH emission feature , to the equivalent width of the 11.25 \mu m PAH feature , which also anti-correlates with the dominance of the AGN .
We measure that the 11.25 \mu m PAH feature has a constant ratio with the H _ { 2 } S ( 1 ) irrespective of Seyfert type , approximately 10 to 1 .
Using the ratio of accurate flux measurements at about 19 \mu m with the two spectrometer channels , having aperture areas differing by a factor 4 , we measured the source extendness and correlated it with the emission line and PAH feature equivalent widths .
The extendness of the source gives another measure of the AGN dominance and correlates both with the EWs of [ NeII ] and PAH emission .
Using the rotational transitions of H _ { 2 } we were able to estimate temperatures ( 200-300K ) and masses ( 1-10 \times 10 ^ { 6 } M _ { \sun } ) , or significant limits on them , for the warm molecular component in the galaxies observed .
Finally we used the ratios of the doublets of [ NeV ] and of [ SIII ] to estimate the gas electron density , which appears to be of the order of n _ { e } \sim 10 ^ { 3 - 4 } cm ^ { -3 } for the highly ionized component and a factor 10 lower for the intermediate ionization gas .