The complex Fe line in the quasar E1821+643 comma Exploiting Unfavorable Space Weathe

An XMMNewton deep exposure and variability monitoring of the Xray brightquasar E1821+643 is proposed. The main aim is to constrain the highly complexiron line profile and its variability: are the very different profiles observedreally different, showing iron line fluctuations in both emission andabsorption? or are the differences mostly due to lack of S/N in the availabledata?. The merged spectrum will provide unprecedent data quality to be used asdiagnostic for the black hole properties and for the structure and ionizationdegree of the iron emission line regions. We propose frequent 5ks observationsat a very low cost for XMMNewton because the target has proven robust enoughagainst high radiation environment, hence optimizing the XMMNewton use. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]