Related papers: Accretion rates and accretion efficiency in AGNs
A tight correlation of black hole mass and central velocity dispersion has been found recently for both active and quiescent galaxies. By applying this correlation, we develop a simple method to derive the inclination angles for a sample of…
Radiative efficiency in radio-loud AGN is governed by the scaled accretion rate on to the central black hole rather than directly by the type of accreted matter; while it correlates with real physical differences, it does not give us…
We analyze the broadband photometric light curves of Seyfert 1 galaxies from the Sergeev et al. (2005) sample and find that a) perturbations propagating across the continuum emitting region are a general phenomenon securely detected in most…
In the past few years more and more pieces of evidence have been presented for a revision of the widely accepted Unified Model of Active Galactic Nuclei. A model based solely on orientation cannot explain all the observed phenomenology. In…
We present 6 cm Very Large Array observations of the Greene & Ho (2004) sample of 19 low-mass active galaxies with high accretion rates. This is one of the only studies of a uniform sample of narrow-line Seyfert 1 (NLS1) galaxies with such…
Understanding the interplay between black-hole accretion and star formation, and how to disentangle the two, is crucial to our understanding of galaxy formation and evolution. To investigate, we use a combination of optical and…
In this paper we present evidence suggesting that the absence or presence of Hidden Broad Line Regions (HBLRs) in Seyfert 2 galaxies is regulated by the rate at which matter accretes onto a central supermassive black hole, in units of…
We show how accretion rate governs the physical properties of a sample of unobscured broad-line, narrow-line, and lineless active galactic nuclei (AGNs). We avoid the systematic errors plaguing previous studies of AGN accretion rate by…
Recently, reliable mass estimates for the central black holes in AGN became feasible due to emission-line reverberation techniques. Using this method as a calibrator, it is possible to determine black hole masses for a wide range of AGN, in…
Radio observations allow us to identify a wide range of active galactic nuclei (AGN), which play a significant role in the evolution of galaxies. Amongst AGN at low radio-luminosities is the 'radio-quiet' quasar (RQQ) population, but how…
We study the link between the X-ray emission in radio-quiet AGNs and the accretion rate on the central Supermassive Black-Hole (SMBH) using a well-defined and statistically complete sample of 70 type1 AGNs extracted from the XMM-Newton…
Accretion rates in radio galaxies are typically estimated from optical and total radio flux measurements, incorporating emission from the core, jets, and lobes. These estimates can be used to investigate the link between observed Active…
Recent observations of Seyfert 1 AGN with Chandra, XMM-Newton and Suzaku revealed broad iron K_alpha emission lines, some relativistically blurred. For galactic black hole X-ray binaries XMM-Newton spectra during hard state also reveal the…
Low-luminosity AGNs are perceived to be radio loud and devoid of a ``big blue bump'', indicating a transition from a radiatively efficient, geometrically thin, accretion disc in high-luminosity AGNs, to a geometrically thick, radiatively…
We present a novel method to measure the accretion rate of radio emitting X-ray binaries (XRBs) and active galactic nuclei (AGN) independently of the X-ray luminosity. The radio emission of the jet is used as a tracer for the accretion rate…
Roughly 10% of quasars are "radio-loud", producing copious radio emission in large jets. The origin of the low-level radio emission seen from the remaining 90% of quasars is unclear. Observing a sample of eight radio-quiet quasars with the…
The X-ray properties of Active Galactic Nuclei (AGNs) depend on their underlying physical parameters, particularly the accretion rate. We identified eight reverberation-mapped AGNs with some of the largest known accretion rates without…
We compare the Spectral Energy Distribution (SED) of radio-loud and radio-quiet AGNs in three different samples observed with SDSS: radio-loud AGNs (RLAGNs), Low Luminosity AGNs (LLAGNs) and AGNs in isolated galaxies (IG-AGNs). All these…
We present the results from a study of the X-ray variability and the near-IR to X-ray spectral energy distribution of four low-luminosity, Seyfert 1 galaxies. We compared their variability amplitude and broad band spectrum with those of…
We present a high density disc reflection spectral analysis of a sample of 17 Seyfert 1 galaxies to study the inner disc densities at different black hole mass scales and accretion rates. All the available XMM-Newton observations in the…