Companion star reflection during the low-state of Hercules X-1

Compton reflection is an important contributor to the energy budgets of AGN andblack hole binaries. However characterizing and quantifying reflection isdifficult because it is dominated by the central source of Xrays. RXTEobservations of the Xray binary Her X1 have revealed a light curve consistentwith reflection from the inner facing hemisphere of the companion star duringthe source.s Xray lowstate (the result of obscuration by an edgeon accretiondisk). We request an XMMNewton observation to confirm this reflection usingspectral diagnostics. Stellar masses, binary size, geometry, temperarture,density, composition and the central irradiating spectrum are wellknown. Thismakes Her X1 a potential calibrator of reflection physics. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]