Related papers: Classifying AGN by X-ray Hardness Variability
The radio-X-ray slope in the fundamental plane of radio-loud active galactic nuclei (AGNs) is found to be steeper compared with that of radio-quiet AGNs in previous works. In this work, we reinvestigate the fundamental plane in radio-loud…
The nuclear regions of active galactic nuclei (AGNs) likely host clumpy clouds that occasionally obscure the central X-ray source, causing eclipse events. These events offer a unique opportunity to study the properties and origins of such…
We analyze the X-ray properties for a sample of 23 high probability AGN candidates with ultraviolet variability identified in Wasleske et al. (2022). Using data from the Chandra X-ray Observatory and the XMM-Newton Observatory, we find…
We present results of an infrared-to-X-ray study of 76 bright soft X-ray selected Seyfert galaxies discovered in the ROSAT All-Sky Survey. These objects are characterized by steep X-ray spectra in the 0.2-2.0 keV bandpass with power law…
The X-ray variability of the Active Galactic Nuclei (AGN) has been most often investigated with studies of individual, nearby, sources, and only a few ensemble analyses have been applied to large samples in wide ranges of luminosity and…
We discuss a model of X-ray variability of active galactic nuclei (AGN). We consider multiple spots which originate on the surface of an accretion disk following intense irradiation by coronal flares. The spots move with the disk around the…
We present results of our Power Spectral Density (PSD) analysis of 30 AGN using the 58 month light curves from Swift's Burst Alert Telescope (BAT) in the 14-150 keV band. PSDs were fit using a Monte Carlo based algorithm to take into…
The question as to whether the distribution of radio-loudness in active galactic nuclei (AGN) is actually bimodal has been discussed extensively in the literature. Futhermore, there have been claims that radio-loudness depends on black hole…
Identifying Active Galactic Nuclei (AGNs) through their X-ray emission is efficient, but necessarily biased against X-ray-faint objects. We aim to characterize this bias by comparing X-ray-selected AGNs to the ones identified through…
Active Galactic Nuclei (AGN), Seyfert galaxies and quasars, are powered by luminous accretion and often accompanied by winds which are powerful enough to affect the AGN mass budget, and whose observational appearance bears an imprint of…
Context. Variability is a ubiquitous feature of active galactic nuclei (AGNs), and the characterisation of the variability is crucial to constrain its physical mechanism and proper applications in AGN studies. The advent of all-sky and…
Active Galactic Nuclei (AGN) are believed to be powered by accretion of matter onto a supermassive black hole. A fundamental ingredient in shaping our understanding of AGN is their variability across the entire electromagnetic spectrum.…
The unified model of active galactic nuclei (AGN) includes a toroidal obscuring structure to explain the differences between Type I and Type II AGN as an effect of inclination angle. This toroidal structure is thought to be 'clumpy' as the…
Analysis of the frequency and physical properties of galaxies with star-formation and AGN activity in different environments in the local universe is a cornerstone for understanding structure formation and galaxy evolution. We have built a…
The Swift Burst Alert Telescope (BAT) survey of Active Galactic Nuclei (AGN) is providing an unprecedented view of local AGNs (<z> = 0.03) and their host galaxy properties. In this paper, we present an analysis of the optical spectra of a…
We map the co-eval growth of galaxies and their central supermassive black holes in detail by measuring the incidence of Active Galactic Nuclei (AGN) in galaxies as a function of star formation rate (SFR) and redshift (to z~4). We combine…
The supermassive black holes in active galactic nuclei (AGN) and stellar-mass black holes in X-ray binaries (XRBs) are believed to work in a similar way. While XRBs evolve rapidly and several sources have undergone a few complete cycles…
Context. A defining characteristic of active galactic nuclei (AGN) that distinguishes them from other astronomical sources is their stochastic variability, which is observable across the entire electromagnetic spectrum. Upcoming optical…
Over the last 12 years, AGN monitoring by RXTE, has revolutionised our understanding of the X-ray variability of AGN, of the relationship between AGN and Galactic black hole X-ray binaries (BHBs) and hence of the accretion process itself,…
A wide-frequency radio study of Active Galactic Nuclei (AGN) is crucial to evaluate the intervening radiative mechanisms responsible for the observed emission and relate them with the underlying accretion physics. We present wide frequency…