Jin-Ming Bai

Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. IV. H

We have completed two years of photometric and spectroscopic monitoring of a large number of active galactic nuclei (AGNs) with very high accretion rates. In this paper, we report on the result of the second phase of the campaign, during 2013-2014, and the measurements of five new H beta time lags out of eight monitored AGNs. All five objects were identified as super-Eddington accreting massive black holes (SEAMBHs). The highest measured accretion rates for the objects in this campaign are (M) over dot(center dot) greater than or similar to 200, (M) over dot(center dot) = M over dot(center dot)/L(Edd)c(-2), (M) over dot(center dot) is the mass accretion rates, L-Edd is the Eddington luminosity and c is the speed of light. We find that the H beta time lags in SEAMBHs are significantly shorter than those measured in sub-Eddington AGNs, and the deviations increase with increasing accretion rates. Thus, the relationship between broad-line region size (R-H beta) and optical luminosity at 5100 angstrom, R-H beta-L-5100, requires accretion rate as an additional parameter. We propose that much of the effect may be due to the strong anisotropy of the emitted slim-disk radiation. Scaling R-H beta by the gravitational radius of the black hole (BH), we define a new radius-mass parameter (Y) and show that it saturates at a critical accretion rate of (M) over dot(c) = 6 similar to 30, indicating a transition from thin to slim accretion disk and a saturated luminosity of the slim disks. The parameter Y is a very useful probe for understanding the various types of accretion onto massive BHs. We briefly comment on implications to the general population of super-Eddington AGNs in the universe and applications to cosmology.

\beta

As a natural consequence of cosmological hierarchical structure formation, sub-parsec supermassive black hole binaries (SMBHBs) should be common in galaxies but thus far have eluded spectroscopic identification. Based on four decades of optical spectroscopic monitoring, we report that the nucleus of NGC 5548, a nearby Seyfert galaxy long suspected to have experienced a major merger about 1 billion yr ago, exhibits long-term variability with a period of similar to 14 yr in the optical continuum and broad H beta emission line. Remarkably, the double-peaked profile of H beta shows systematic velocity changes with a similar period. These pieces of observations plausibly indicate that an SMBHB resides in the center of NGC 5548. The complex, secular variations in the line profiles can be explained by orbital motion of a binary with equal mass and a semimajor axis of similar to 22 light-days (corresponding to similar to 18 milli-parsec). At a distance of 75 Mpc, NGC 5548 is one of the nearest sub-parsec SMBHB candidates that offers an ideal laboratory for gravitational wave detection.

Time Lags and Implications for Super-Eddington Accretion

This is the third in a series of papers reporting on a large reverberation-mapping campaign aimed to study the properties of active galactic nuclei (AGNs) with high accretion rates. We present new results on the variability of the optical Fe II emission lines in 10 AGNs observed by the Yunnan Observatory 2.4m telescope during 2012--2013. We detect statistically significant time lags, relative to the AGN continuum, in nine of the sources. This accurate measurement is achieved by using a sophisticated spectral fitting scheme that allows for apparent flux variations of the host galaxy, and several narrow lines, due to the changing observing conditions. Six of the newly detected lags are indistinguishable from the Hbeta lags measured in the same sources. Two are significantly longer and one is slightly shorter. Combining with Fe II lags reported in previous studies, we find a Fe II radius--luminosity relationship similar to the one for Hbeta, although our sample by itself shows no clear correlation. The results support the idea that Fe II emission lines originate in photoionized gas which, for the majority of the newly reported objects, is indistinguishable from the Hbeta-emitting gas. We also present a tentative correlation between the lag and intensity of Fe II and Hbeta and comment on its possible origin.

SPECTROSCOPIC INDICATION OF A CENTI-PARSEC SUPERMASSIVE BLACK HOLE BINARY IN THE GALACTIC CENTER OF NGC 5548

This paper reports results of the third-year campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs) between 2014-2015. Ten new targets were selected from quasar sample of Sloan Digital Sky Survey (SDSS), which are generally more luminous than the SEAMBH candidates in last two years. H

SUPERMASSIVE BLACK HOLES WITH HIGH ACCRETION RATES IN ACTIVE GALACTIC NUCLEI. III. DETECTION OF Fe II REVERBERATION IN NINE NARROW-LINE SEYFERT 1 GALAXIES

beta

Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. V. A New Size–Luminosity Scaling Relation for the Broad-line Region

lags (

SDSS J013127.34-032100.1: A NEWLY DISCOVERED RADIO-LOUD QUASAR AT z=5.18 WITH EXTREMELY HIGH LUMINOSITY

tau_{_{rm Hbeta}}

A NEW APPROACH TO CONSTRAIN BLACK HOLE SPINS IN ACTIVE GALAXIES USING OPTICAL REVERBERATION MAPPING

) in five of the 10 quasars have been successfully measured in this monitoring season. We find that the lags are generally shorter, by large factors, than those of objects with same optical luminosity, in light of the well-known

THE FUNDAMENTAL PLANE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI

R_{_{rm Hbeta}}-L_{5100}

The physical constraints on a new LoBAL QSO at z=4.82

relation. The five quasars have dimensionless accretion rates of