Possible Evidence for a Truncated Thin Disk in Seyfert 1 Galaxy Ngc4593

We compile the multi-band spectral energy distribution (SED) of Seyfert 1 galaxy NGC4593, and investigate its optical-to-ultraviolet (OUV) continuum and iron Kα line profile. No strong “big blue bump” is found in OUV band. The iron Kα line profile is not as broad as expected from a disk which extends down to the last stable orbit. Both of them can be modeled by a truncated thin disk, and support the existence of a truncated thin disk in the system. It is of much interest that NGC4593 may be a typical object with an accretion rate ṁ = Ṁ/MEdd ∼ 0.01−0.1 and harbors a two component accretion flow: an outer thin disk and an inner hot flow–possibly ADAF, analogous to the low and intermediate state of low mass X-ray binaries (LMXB). Subject headings: Accretion, accretion disks–galaxies: individual (NGC4593) –galaxies: active–Seyferts–general