EHT comma XMM-Newton comma NuSTAR comma Chandra Study of the Black Hole MKN 501

The Event Horizon Telescope (EHT) is effectively an Earthsized, interferometricmmband telescope array with 20 microarcsec spatial that is conductinggroundbreaking observations of distant supermassive black hole (SMBH) systemsresolution. These emission size scales are consistent with those inferred fromXray and gammaray variability, thus our request for joint XMMNewton/NuSTAR/Chandra/EHT observations of a particularly interesting SMBH, MKN 501. MKN 501belongs to a subclass of systems that may consist of a close pair of binaryblack holes. Along with contemporaneous EHT observations approved for Spring2019, joint XMMNewton/NuSTAR study of MKN 501 will provide combined broadbandXray spectra and variability, while Chandra can provide arcsecond imaging. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]