TRACKING ACCRETION POWER INTO THE LOW LUMINOSITY REGIME

The accretion flow in AGN changes its structure when the accretion rate drops.High power AGN are softer when brighter while lowluminosity sources do theopposite. The transition point is not well known, largely because of theimprecise determination of the spectral slope, whose dynamic range is verysmall. What happens to the accretion flow at low rates is also not wellunderstood, either a RIAF or a jet are possible. In this proposal we targetthree low accretion rate AGN to measure their spectral slope, and confirm orreject spectral curvature, which would point to a RIAF. The targets belong to aflux limited sample covering a wide range in accretion rates. They fill themidlow L/L Edd range, crucial to follow the evolution of the Xray emission at the turning point. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]