Researches On The Accretion Properties Of Radio-Loud Active Galactic Nuclei

Accretion rate is a fundamental parameter for active galactic nuclei(AGNs)activities.There will be different accretion modes at the center of AGNs when the accretion rate(Eddington ratio)changes,which produce different observational characters of AGNs.The accretion properties of AGNs are not only related to the observational characters of themselves,but also related to the jet formation and the AGN feedback.Because of the intense jet activities,the research on radioloud AGNs is the most active field in AGN researches.For radio-loud AGNs,the non-thermal radiation from jets contributes large fraction of their observational luminosity.Therefore,their Eddington ratio estimations have large uncertainties.Some opposite conclusions have been even reported.To constrain the Eddington ratio,we need the accurate measurement of the central black hole mass firstly.In order to measure the black hole mass with reverberation mapping(RM),we observed two young radio sources with the narrow band photometric.This is the first RM observation for this type of sources.Unfortunately,no lags were found for both sources.But many experiences for target selection and observation strategies are accumulated.Afterwards,the other parameter to constrain the Eddington ratio is the bolometric luminosity from accretion process.We estimate the bolometric luminosity with the observational luminosity of two bands,named the X-ray and optical bands,respectively.The X-ray emission of young radio sources can origin from jets or accretion process.One needs to confirm that the X-ray emission is dominated by the accretion process before it is used to constrain the Eddington ratio.We examine the radio/X-ray correlation and the black hole fundamental plane for young radio sources.There are large deviations between the observation results of young radio sources and the theoretical predictions of the jet dominated X-ray emission.Thus we conclude that the X-ray emission of young radio sources is dominated by the accretion process.Then we estimate the Eddington ratio with the X-ray luminosity.The results show that the Eddington ratios of young radio sources areindeed high.Moreover,there seems no difference between HEGs and LEGs.The analyses of the optical spectra also confirm higher Eddington ratios for young radio sources.And the optical properties of young radio sources are similar with narrow line Seyfert 1 galaxies(NLS1s),except that the width of broad emission lines for young radio sources is larger than that of NLS1 s.Thus the young radio sources could be the high black hole mass counterparts of NLS1 s.Because of the dominated optical and X-ray emission from jets for blazars,we do not estimate their Eddington ratio directly.We first attempt to clarify what determine the observational differences of blazars.This will give some implications for the accretion modes of blazars.We find significantly negative correlation between the synchrotron peak frequency and the Doppler factor.This correlation is consistent with the scenario that the black hole mass governs both the bulk Lorentz factor and the synchrotron peak frequency.In addition,the distinction between the kinetic jet powers of BL Lacs and FSRQs is mainly caused by the different Doppler factors.The negative correlation between the peak frequency and the observational isotropic luminosity,known as the blazar sequence,also disappears after the Doppler boosting is corrected.This means that the cooling effect from the external photon fields is not the main reason to determine the synchrotron peak frequency.Based on all these results,we suggest that it is the black hole mass which determines the bulk Lorentz factor,finally determines the observational differences of blazars.That means the accretion mode is not so important for blazar classifications as suggested by many authors.In addition,we monitor a flare state of a typical FSRQ — 3C 454.3 with the Lijiang 2.4 m telescope and Kunming 1m telescope.3C 454.3 has flared several times at ?-ray band recent years.During the December 2009 flare,the variability of optical and ?-ray emission shows significant correlation with no obvious lag.This result confirms the lepton model for the high energy emission of blazars.Moreover,the color index of 3C 454.3 get red when the optical emission get brighter,which indicate its disk radiation is important at the optical band.