Completing the 3CR X-ray survey: the last unidentified radio sources in the Thir

In the past decade many extragalactic 3CR sources have been observed by Spitzer,Hubble and Chandra as well as in the radio band at different frequencies. Inparticular, we successfully carried out the Xray survey for all the unobserved3CR sources with z<1 with Chandra. However we discovered that 20 sources out of298 are still unidentified. Here we propose a snapshot program with XMMNewtonfollow up observations that will allow to detect the Xray emission arising fromthe core of these unidentified 3CR sources and to improve the localization ofthe optical counterparts. Thanks to the proposed XMMNewton observations we willbe also able to obtain the first Xray observations of obscured radioloudsources in the 3CR catalog since none of those listed as obscured have been yet pointed in the Xrays. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]