Active galactic nuclei ( AGN ) and galactic black hole binaries ( GBHs ) represent two classes of accreting black holes .
They both contain an accretion disc emitting a thermal radiation , and a non-thermal X-ray emitting ’ corona ’ .
GBHs exhibit state transitions and spectral states are characterized by different luminosity levels and shapes of the spectral energy distribution ( SED ) .
If AGN transitioned in a similar way , the characteristic timescales of such transitions would exceed \sim 10 ^ { 5 } years .
Thus a probability to observe an individual AGN transiting between different spectral states is very low .
In this paper we follow a spectral evolution of a GBH GRO J1655-40 and then apply its SED evolution pattern to a simulated population of AGN under a reasonable assumption that a large sample of AGN should contain a mixture of sources in different spectral states .
We model the X-ray spectra of GRO 1655-40 with the eqpair model and then scale the best-fitting models with the black hole mass to simulate the AGN spectra .
We compare the simulated and observed AGN SEDs to determine the spectral states of observed Type 1 AGN , LINER and NLS1 populations .
We conclude that bright Type 1 AGN and NLS1 galaxies are in a spectral state similar to the soft spectral state of GBHs , while the spectral state of LINERs may correspond to the hard spectral state of GBHs .
We find that taking into account a spread in the black hole masses over several orders of magnitude , as in the observed AGN samples , leads to a correlation between the X-ray loudness , \alpha _ { ox } , and a monochromatic luminosity at 2500Å .
We predict that the \alpha _ { ox } correlates positively with the Eddington luminosity ratio down to a critical value of \lambda _ { crit } = L / L _ { E } \approx 0.01 , and that this correlation changes its sign for the accretion rates below \lambda _ { crit } .