ИСТИНА

We investigate the correlation between infrared (JHKL) and optical (B) fluxes of the variable nucleus of the Seyfert galaxy NGC 4151 using our partially published data for 2010-2015. Here we are using the same data as in Oknyansky et al. (2014a,b), but include also our new optical data and published optical and NIR photometric data from Schnuelle et al. (2015). We find that the lag of flux in HKL have the same 37 ± 3 days lags relative to optical variations. Variability in the J and HKL bands is not quite simultaneous, perhaps due to the differing contributions of the accretion disk radiation in these bands. The lag found for the K band compared with the B band is not significantly different from earlier values obtained for the period 2000-2009. However, finding approximately the same lags in HKL bands for 2010-2015 differs from previous results at some earlier epochs when the lag increased with increasing wavelength. About almost the same lags in different IR bands are found very common feature for active nuclei (Oknyansky et al. 2015). In the case of NGC 4151 it appears that the relative lags between the IR bands may be different in differ-ent years depending from variations of luminosity state. The available data allow us to in-vestigate a possible change in the lags during the test interval. We don’t confirm significant change of time lags for JHL in 2013-2014 which was found by Shcnuelle at al., but we found that the AD component with the short time lag in J is became more significant dur-ing 2013-2015. We discuss our results in the framework of the standard model where the variable infrared radiation is mainly due to thermal re-emission from the dusty clouds closest to the central source. There is also a contribution of some IR emission from the accretion disk, and this contribution increases with decreasing wavelength. The absence of the variations and wavelengths independence of the IR (HKL) lags can be explained by location of dust clouds farther than dust sublimation can be happen during 2010-2015. Another possibility to explain near simultaneity of the variability from the near-IR to the mid-IR is that the hot dust is in a hollow bi-conical outflow of which we only see the near side (Oknyansky et al. 2015).