085221

Spin measurements for high-mass active galactic nuclei are currently very sparse comma but are critical for testing correlations between mass and spin hinted at in the current sample of AGN with spin constraints comma and testing theoretical models of supermassive black hole growth. We request a coordinated broadband X-ray observation of PG1426+015 comma which has the largest reverberation-mapped mass to date openParlogCORCHETE_OPENMbh-MsunCORCHETE_CLOSE = 9.01 openPar+0.11 comma -0.16closeParclosePar comma with XMM-Newton openPar100ksclosePar and NuSTAR openPar100ksclosePar. The quality of the data will enable us to robustly search for relativistically broadened iron emission comma an unambigous signature of reflection from the innermost accretion disc comma and take an important first step towards constrining the spin for this key source.