Related papers: Exploring the quasar disc-wind-jet connection with…
Based on recent X-ray observations, ultra-fast outflows from supermassive black holes are expected to have enough energy to dramatically affect their host galaxy but their launch and acceleration mechanisms are not well understood. We…
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…
A recent analysis of black hole scaling relations, used to estimate the local mass density in black holes, has indicated that the normalization of the scaling relations should be increased by approximately a factor of five. The local black…
The accretion/ejection coupling in accreting black hole binaries has been described by empirical relations between the X-ray/radio and X-ray/optical-infrared luminosities. These correlations were initially supposed to be universal. However,…
We present a comprehensive study of the physical origin of radio emission in optical quasars at redshifts z < 2.5. We focus particularly on the associations between compact radio emission, dust reddening, and outflows identified in our…
We present a feedback mechanism for supermassive black holes and their host bulges that operates during epochs of radio-loud quasar activity. In the radio cores of relativistic quasar jets, internal shocks convert a fraction of ordered bulk…
We investigate the dichotomy in the radio loudness distribution of quasars by modelling their radio emission and various selection effects using a Monte Carlo approach. The existence of two physically distinct quasar populations, the…
Radio-loud high-redshift quasars (RHRQs) provide crucial insights into the evolution of relativistic jets and their connection to the growth of supermassive black holes. Beyond the extensively studied population at $z \ge 5$, the cosmic…
Accreting stellar-mass black holes appear to populate two branches in a radio:X-ray luminosity plane. We have investigated the X-ray variability properties of a large number of black hole low-mass X-ray binaries, with the aim of unveiling…
Recent works show that the radio power of quasars accreting at very high rates can reach surprisingly high values. These studies suggest that this radio emission might originate from star formation, but lack of data leaves open the…
When the matter from a companion star is accreted towards the central compact accretor, i.e. a black hole (BH) or a neutron star (NS), an accretion disc and a jet outflow will form, providing bight X-ray and radio emission, which is known…
Black holes of stellar mass and neutron stars in binary systems are first detected as hard X-ray sources using high-energy space telescopes. Relativistic jets in some of these compact sources are found by means of multiwavelength…
Accreting black holes produce powerful relativistic plasma jets which emit radiation across all observable wavelengths but the details of the initial acceleration and confinement of the jet are uncertain. We apply an innovative new model…
Studying the variability of the accretion disks of black holes and jets is important to identify their internal physical processes. In this letter, we obtain the characteristic damping timescale of 34 blazars and seven microquasars from the…
We present a study of the mechanical power generated by both winds and jets across the black hole mass scale. We begin with the study of ionized X-ray winds and present a uniform analysis using Chandra grating spectra. The high quality…
We derived the black hole fundamental plane relationship among the 1.4GHz radio luminosity (L_r), 0.1-2.4keV X-ray luminosity (L_X), and black hole mass (M) from a uniform broad line SDSS AGN sample including both radio loud and radio quiet…
Virial black-hole mass estimates are presented for 12698 quasars in the redshift interval 0.1<z<2.1, based on modelling of spectra from the Sloan Digital Sky Survey (SDSS) first data release . The black-hole masses of the SDSS quasars are…
We assess evolution in the black hole mass - stellar velocity dispersion relationship (M-sigma relationship) for quasars in the Sloan Digital Sky Survey Data Release 7 for the redshift range 0.1 < z < 1.2. We estimate the black hole mass…
Disc accretion on to a black hole is often misaligned from its spin axis. If the disc maintains a significant magnetic field normal to its local plane, we show that dipole radiation from Lense-Thirring precessing disc annuli can extract a…
Starting from the quasar sample of the Sloan Digital Sky Survey (SDSS) for which the CIV line is observed, we use an analysis scheme to derive the z-dependence of the maximum mass of active black holes, which overcomes the problems related…