相关论文: Two Different Accretion Classes in Seyfert 1 Galax…

We present a comprehensive study of the spectrum of the narrow-line Seyfert 1 galaxy RE J1034+396, summarizing the information obtained from the optical to X-rays with observations from the William Herschel 4.2m Telescope (WHT), the Hubble…

Unified models of Seyfert galaxies, based on viewing angles, successfully explain the observed differences between type 1 and 2 Seyferts. The existence of a range in accretion rates relative to the Eddington rate (from broad-line Seyfert 1s…

We describe new optical images and spectra of POX 52, a dwarf galaxy with an active nucleus that was originally detected in the POX objective-prism survey. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an…

We estimate black hole masses and Eddington ratios for a sample of 81 young radio galaxies (42 CSS +39 GPS). We find that the average black hole (BH) mass of these young radio galaxies is <log Mbh>~8.3, which is less than that of radio loud…

It is commonly believed that accretion discs are truncated and their inner regions are described by advection dominated accretion flows (ADAFs) in the hard spectral state of black hole X-ray binaries. However, the increasing occurrence of a…

The `fundamental plane of black hole accretion' (FP), a relation between the radio luminosities ($L_R$), X-ray luminosities ($L_X$), and masses ($M_{BH}$) of hard/quiescent state black hole binaries and low-luminosity active galactic…

There is growing evidence to suggest that the black hole mass has been previously underestimated with the H$\beta$ line width for certain active galactic nuclei (AGN). With the assumption of the flatter rather than isotropic velocity…

ASCA observations of Narrow-Line Seyfert 1 galaxies (NLS1s) are presented. We focus on the black hole size of the NLS1 sources by employing two independent methods for the mass estimation; one is using X-ray variability, the other is using…

Aims: The unification scheme of Seyfert galaxies predicts that the observed differences between type 1 and type 2 Seyfert galaxies are solely due to the differing orientations of the toroidal-shaped obscuring material around AGN. The…

We review the current status of the understanding how the accretion onto the central black hole proceeds in Active Galaxies. Standard accretion disk is a key element in all relatively bright active galaxies like Seyferts and quasars,…

We present a deep study of the average hard X-ray spectra of Seyfert galaxies. We analyzed all public INTEGRAL IBIS/ISGRI data available on all the 165 Seyfert galaxies detected at z<0.2. Our final sample consists of 44 Seyfert 1's, 29…

The interaction of a supermassive black hole with the matter of an accretion disk in the presence of a magnetic field is the key mechanism of energy release in active galactic nuclei. However, determining the physical parameters of this…

We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hbeta reverberation lag measurements for several relatively low-luminosity…

Black hole mass determination in active galaxies is a key issue in understanding various luminosity states. In the present paper we try to generalise the mass determination method based on the X-ray excess variance, successfully used for…

The $BeppoSAX$ archive is currently the largest reservoir of high sensitivity simultaneous soft and hard-X ray data of Seyfert galaxies. From this database all the Seyfert galaxies (105 objects of which 43 are type I and 62 are type II)…

We present HST/ACS observations of ten galaxies that host narrow-line Seyfert 1 (NLS1) nuclei, believed to contain relatively smaller mass black holes accreting at high Eddington ratios. We deconvolve each ACS image into a nuclear point…

We have conducted a systematic search of low-mass black holes (BHs) in active galactic nuclei (AGNs) with broad Halpha emission lines, aiming at building a homogeneous sample that is more complete than previous ones for fainter, less highly…

We investigate accretion disc models for the X-ray emission of Seyfert-1 galaxies and the hard state of black-hole X-ray binaries. We concentrate on two hot accretion disc models: advection-dominated accretion flow (ADAF) and recently found…

A solid theoretical understanding of how inflowing, accreting plasma around black holes and other compact objects gives rise to outflowing winds and jets is still lacking, despite decades of observations. The fact that similar processes and…

At luminosities below a few percent of Eddington, accreting black holes switch to a hard spectral state which is very different from the soft blackbody-like spectral state that is found at higher luminosities. The hard state is…