We propose to take a 3rd-epoch spectrum of a drastically fading quasar with Keck/LRIS. This quasar shows a large gradual brightness decline over 20 years, in total, by a factor of ∼100 in the AGN component, making it a good AGN candidate in which AGN activity shuts down in a short time scale. A new (3rd-epoch) Keck/LRIS spectrum will enable us to measure how much more fading its broad line emission lines (CIV, CIII], and MgII) are, what the host galaxy is, and to see the accretion state transition from standard accretion to RIAF-like accretion. We also propose NIR imaging with Subaru/MOIRCS to get the first significant constraint on the stellar component of the host galaxy of this quasar. This enables us to reliably decompose the total spectral energy distribution into the two (AGN+host) components and compare the host properties of this fading quasar with those of other quasars.
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