相关论文: Scaling variability from stellar to supermassive b…

The innermost regions in active galactic nuclei (AGNs) were not being spatially resolved so far but spectropolarimetry can provide us insight about their hidden physics and the geometry. From spectropolarimetric observations in broad…

Our understanding of highly accreting AGNs is hampered by the lack of a complete systematic investigation in terms of their main spectral and variability properties, and by the relative paucity of them in the local Universe, especially…

Black hole low-mass X-ray binaries show a variety of variability features, which manifest themselves as narrow peak-like structures superposed on broad noise components in power density spectra in the hard X-ray emission. In this work we…

Recent studies have revealed strong correlations between 1-10 Hz frequencies of quasiperiodic oscillations (QPOs) and the spectral power law index of several Black Hole (BH) candidate sources when seen in the low/hard state, the steep…

We characterize the optical variability of quasars in the intermediate Palomar Transient Factory (iPTF) and Palomar Transient Factory (PTF) surveys. We re-calibrate the $r$-band light curves for $\sim$28,000 luminous, broad-line AGNs from…

As a newly discovered class of radio-loud active galactic nuclei (AGNs), the \gamma-ray detected narrow-line Seyfert 1 galaxies (NLS1s) launch powerful jets which are generally found only in blazars and radio galaxies. However, their black…

How Supermassive Blackholes (SMBHs) are spun-up is a key issue of modern astrophysics. As an extension of the study in Wang et al. (2016), we here address the issue by comparing the host galaxy properties of nearby ($z<0.05$) radio-selected…

Four persistent (Cygnus X-1, GX 339-4, GRS 1758-258 and 1E 1740.7-2942) and three transient (GS 2023+38, GRO J0422+32 and GS 1354-64) black hole X-ray binary systems have been extensively observed at radio wavelengths during extended…

We present a series of monitoring observations of the ultrasoft broad-line AGN RE J2248-511 with XMM-Newton. Previous X-ray observations showed a transition from a very soft state to a harder state five years later. We find that the…

The All Sky Monitor (ASM) onboard the Rossi X-ray Timing Explorer (RXTE) has continuously monitored a number of Active galactic nuclei (AGNs) with similar sampling rates for 14 years from 1996 January to 2009 December. Utilizing the…

The physical origin of active galactic nucleus (AGN) variability remains unclear. Here we propose that the magnetic reconnection induced by the migration of satellite black holes (sBHs) in the AGN disk can be a new plausible mechanism for…

At the highest redshifts, z>6, several tens of luminous quasars have been detected. The search for fainter AGN, in deep X-ray surveys, has proven less successful, with few candidates to date. An extrapolation of the relationship between…

The changing-look active galactic nucleus (CL-AGN), an extraordinary subpopulation of supermassive black holes, has attracted growing attention for understanding its nature. We present an analysis of the spectral properties of 203…

I will describe the constraints available from a study of AGN evolution synthesis models on the growth of the supermassive black holes (SMBH) population in the two main 'modes' observed (kinetic- and radiatively-dominated, respectively). I…

In this work we have developed a new stochastic model for the fluctuations in lightcurves of accreting black holes. The model is based on a linear combination of stochastic processes and is also the solution to the linear diffusion equation…

(Abriged) We report on the measurement of the rest frame K-band luminosity and total stellar mass of the hosts of 89 broad line Active Galactic Nuclei detected in the zCOSMOS survey in the redshift range 1<z<2.2. The unprecedented…

PG1535+547 is a bright NLS1 galaxy, whose high energy emission shows strong variability in shape and flux. ROSAT data classified it as soft X-ray weak QSO (objects whose X-ray-to-optical flux ratio is smaller than in typical QSO): their…

We present ASCA data on RE J2248-511, extending existing optical and soft X-ray coverage to 10 keV, and monitoring the soft component. These data show that, despite a very strong ultrasoft X-ray excess below 0.3 keV and a soft 0.3--2 keV…

The old EXOSAT medium energy measurements of high frequency (HF) AGN power spectral normalisation are re-examined in the light of accurate black hole mass determinations which were not available when these data were first published (Green…

We present Space Telescope Imaging Spectrograph observations from the Hubble Space Telescope of the supermassive black hole (SMBH) at the center of PKS0745-191, a brightest cluster galaxy (BCG) undergoing powerful radio-mode AGN feedback…