Limited studies have been performed on the radio-loud fraction in X-ray selected type 1 AGN samples. The consistency between various radio-loudness definitions also needs to be checked. We measure the radio-loudness of the 407 type 1 AGNs in the XMM-
COSMOS quasar sample using nine criteria from the literature (six defined in the rest-frame and three defined in the observed frame): $R_L=log(L_{5GHz}/L_B)$, $q_{24}=log(L_{24mu m}/L_{1.4GHz})$, $R_{uv}=log(L_{5GHz}/L_{2500AA})$, $R_{i}=log(L_{1.4GHz}/L_i)$, $R_X=log( u L_{ u}(5GHz)/L_X)$, $P_{5GHz}=log(P_{5GHz}(W/Hz/Sr))$, $R_{L,obs}=log(f_{1.4GHz}/f_B)$ (observed frame), $R_{i,obs}=log(f_{1.4GHz}/f_i)$ (observed frame), and $q_{24, obs}=log(f_{24mu m}/f_{1.4GHz})$ (observed frame). Using any single criterion defined in the rest-frame, we find a low radio-loud fraction of $lesssim 5%$ in the XMM-COSMOS type 1 AGN sample, except for $R_{uv}$. Requiring that any two criteria agree reduces the radio-loud fraction to $lesssim 2%$ for about 3/4 of the cases. The low radio-loud fraction cannot be simply explained by the contribution of the host galaxy luminosity and reddening. The $P_{5GHz}=log(P_{5GHz}(W/Hz/Sr))$ gives the smallest radio-loud fraction. Two of the three radio-loud fractions from the criteria defined in the observed frame without k-correction ($R_{L,obs}$ and $R_{i,obs}$) are much larger than the radio-loud fractions from other criteria.
The mid-infrared to ultraviolet (0.1 -- 10 $mu m$) spectral energy distribution (SED) shapes of 407 X-ray-selected radio-quiet type 1 AGN in the wide-field ``Cosmic Evolution Survey (COSMOS) have been studied for signs of evolution. For a sub-sample
of 200 radio-quiet quasars with black hole mass estimates and host galaxy corrections, we studied their mean SEDs as a function of a broad range of redshift, bolometric luminosity, black hole mass and Eddington ratio, and compared them with the Elvis et al. (1994, E94) type 1 AGN mean SED. We found that the mean SEDs in each bin are closely similar to each other, showing no statistical significant evidence of dependence on any of the analyzed parameters. We also measured the SED dispersion as a function of these four parameters, and found no significant dependencies. The dispersion of the XMM-COSMOS SEDs is generally larger than E94 SED dispersion in the ultraviolet, which might be due to the broader ``window function for COSMOS quasars, and their X-ray based selection.
The Cosmic Evolution Survey (COSMOS) enables the study of the Spectral Energy Distributions (SEDs) of Active Galactic Nuclei (AGN) because of the deep coverage and rich sampling of frequencies from X-ray to radio. Here we present a SED catalog of 413
X-ray (xmm) selected type 1 (emission line FWHM$>2000$ km s$^{-1}$) AGN with Magellan, SDSS or VLT spectrum. The SEDs are corrected for the Galactic extinction, for broad emission line contributions, constrained variability, and for host galaxy contribution. We present the mean SED and the dispersion SEDs after the above corrections in the rest frame 1.4 GHz to 40 keV, and show examples of the variety of SEDs encountered. In the near-infrared to optical (rest frame $sim 8mu m$-- 4000AA), the photometry is complete for the whole sample and the mean SED is derived from detections only. Reddening and host galaxy contamination could account for a large fraction of the observed SED variety. The SEDs are all available on-line.
