On the physical state in narrow-line region of the classical Seyfert galaxy NGC 7469

The classical Sy1 galaxy NGC 7469 was investigated on the basis of absolute spectrometric data and on recently obtained spectrograms. The spectral data in the visible region (lambda lambda 3150-10660 A) allow to extract some parameters of the ionizing radiation spectrum energies above 13,6 eV and up to more than 175 eV. The nonthermal luminosity at the Lyman continuum frequency ν0, evaluated from the Hsub(β) line, was 1,5x1028 ergs. S-1. Hz-1. The temperature Tsub(e) in the narrow-line region (NLR) was found to be approx. or approx.= 23000 K for nsub(e) approx. or approx.= 105 sm-3. This temperature is sufficiently high and is related to the deeper nuclear regions with a higher ionization degree. A comparison of Tsub(e) values in the NLR of Sy1 with those of Sy2 was made. The differences in the mean Tsub(e) for both SyG classes are probably due to the small (approx. 0,1 pc) dense (nsub(e) approx. 1010 cm-3) region existing in Sy1, which causes full absorption of the low-energy quanta. The gas is heated mainly by X-radiation whereas in Sy2 the absence of such region permits the low-energy quanta to penetrate the NLR and to heat the gas effectively. Thus, Osterbrock's idea (Astron. J. 84, 1979, 901) about the geometrical differences in the nuclear regions of Sy1 and Sy2 is borne out