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We select a sample of radio galaxies at high redshifts (z>~1) in the COSMOSfield, by cross-matching optical/infrared images with the FIRST radio data. Theaim of this study is to explore the high-z radio-loud (RL) AGN population atmuch lower luminosities than the classical samples of distant radio sources andsimilar to those of the local population of radio galaxies. The widemultiwavelength coverage provided by the COSMOS survey allows us to derivetheir Spectral Energy Distributions (SEDs). The SED modeling with stellar anddust components (with our code 2SPD) returns several important quantitiesassociated with the AGN and host properties. The final sample consists of 74 RLAGN, which extends the sample previously selected by Chiaberge et al. (2009)and studied by Baldi et al. (2013). The resulting photometric redshifts rangefrom z~0.7 to 3. The sample mostly includes compact radio sources, but also 21FRIIs; the radio power distribution of the sample at 1.4 GHz covers~10^(31.5)-10^(34.3) \erg\s\Hz. The stellar mass of the hosts ranges~10^(10)-10^(11.5) M_{sun}. The SEDs are dominated by the contribution from anold stellar population for most of the sources. UV and mid-IR (MIR) excessesare observed for half of the sample. The dust luminosities are in the rangeL_(dust) ~10^(43)-10^(45.5) erg/s (T ~350-1200 K). UV luminosities at 2000 Aranges ~10^(41.5)-10^(45.5) erg/s. UV emission is significantly correlated withboth IR and radio luminosities, the former being the stronger link. However,the origin of UV and dust emission, whether it is produced by the AGN of bystar formation, is still unclear. Our results show that this RL AGN populationat high redshifts displays a wide variety of properties from possible quasarsat the highest luminosities, to low-luminosity old galaxies, similarly to thelocal FRI-FRII dichotomy.

The radio-loud AGN population at z>~1 in the COSMOS field. I. Selection and Spectral Energy Distributions