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As a step toward a comprehensive overview of the infrared diagnostics of thecentral engines and host galaxies of quasars at low redshift, we presentSpitzer Space Telescope spectroscopic (5-40 {\mu}m) and photometric (24, 70 and160 {\mu}m) measurements of all Palomar-Green (PG) quasars at z < 0.5 and 2MASSquasars at z < 0.3. We supplement these data with Herschel measurements at 160{\mu}m. The sample is composed of 87 optically selected PG quasars and 52near-IR selected 2MASS quasars. Here we present the data, measure the prominentspectral features, and separate emission due to star formation from thatemitted by the dusty circumnuclear torus. We find that the mid-IR (5-30 {\mu}m)spectral shape for the torus is largely independent of quasar IR luminositywith scatter in the SED shape of ~ 0.2 dex. Except for the silicate features,no large difference is observed between PG (unobscured - silicate emission) and2MASS (obscured - silicate absorption) quasars. Only mild silicate features areobserved in both cases. When in emission, the peak wavelength of the silicatefeature tends to be longer than 9.7 {\mu}m, possibly indicating effects ongrain properties near the AGN. The IR color is shown to correlate with theequivalent width of the aromatic features, indicating that the slope of thequasar mid- to far-IR SED is to first order driven by the fraction of radiationfrom star formation in the IR bands.

Infrared spectra and photometry of complete samples of PG and 2MASS quasars