Related papers: Periodic variability and binary black hole systems…

Graham et al. (2015) have detected a 5.2 year periodic optical variability of the quasar PG 1302-102 at redshift $z=0.3$, which they interpret as the redshifted orbital period $(1+z)t_{\rm bin}$ of a putative supermassive black hole binary…

A study of the statistics of cosmological black-hole jet sources is applied to EGRET blazar data, and predictions are made for GLAST. Black-hole jet sources are modeled as collimated relativistic plasma outflows with radiation beamed along…

Our aim is to show how variable Doppler boosting of an intrinsically variable jet can explain the long-term modulation of 1667 \pm 8 days observed in the radio emission of LSI+61303. The physical scenario is that of a conical, magnetized…

Relativistic effects dominate the emission of blazar jets complicating our understanding of their intrinsic properties. Although many methods have been proposed to account for them, the variability Doppler factor method has been shown to…

We investigate the variability properties of blazars in the GeV band using the data of the Fermi/LAT telescope. We find that blazars exhibit variability on the scales down to the minimal timescale resolvable by Fermi, which is a function of…

One of the proposed explanations for the broad, double-peaked Balmer emission lines observed in the spectra of some active galactic nuclei (AGNs) is that they are associated with sub-parsec supermassive black hole (SMBH) binaries. Here, we…

Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and hence the feedback they provide to their surroundings, depends strongly…

The majority of fast millisecond pulsars are in binary systems, so that any periodic signal they emit is modulated by both Doppler and relativistic effects. Here we show how well-established binary models can be used to account for these…

We use long-run, high-resolution hydrodynamics simulations to compute the multi-wavelength light curves (LCs) from thermal disk emission around accreting equal-mass supermassive black hole (BH) binaries, with a focus on revealing binary…

We present X-ray observations of the Black-Hole Binary GRS 1915+105 made with the RXTE (Rossi X-ray Timing Explorer). We concentrated on timing analysis of the strong variability focusing on its aperiodic variability on short (<1s) time…

In a two-component jet model, the emissions are the sum of the core and extended emissions: $S^{\rm ob}=S_{\rm core}^{\rm ob}+S_{\rm ext}^{\rm ob}$, with the core emissions, $S_{\rm core}^{\rm ob}= f S_{\rm ext}^{\rm ob}\delta^{q}$, being a…

We consider the shock structures that can arise in blazar jets as a consequence of variations in the jet flow velocity. There are two possible cases: (1) A double shock system consisting of both a forward and reverse shock (2) A single…

Kinematical and luminosity relations for black-hole jet sources are reviewed. If the TeV flares observed from PKS 2155-304 in 2006 July are assumed to originate from a black hole with mass $\approx 10^8 M_8 M_\odot$, then the $\sim 5$…

Relativistic jets from supermassive black holes in active galactic nuclei are amongst the most powerful phenomena in the universe, acting to regulate the growth of massive galaxies. Similar jets from stellar-mass black holes offer a chance…

During the last 40-50 years, the TeV blazar Ton 599 has systematically experienced major outbursts detected in a wide wavelength range from radio to $\gamma$-rays. In this work, we present an analysis of Ton 599 quasi-periodic variability…

In this paper, we investigated the issue of black hole masses and minimum timescales of jet emission for blazars. We proposed a sophisticated model that sets an upper limit to the central black hole masses $M_{\bullet}$ with the minimum…

Variability is a typical observation feature of Fermi blazars, sometimes it shows quasi-periodic oscillation (QPO). In this work, we obtained 5-day binned light curves (with a time coverage of $\sim$ 12.9 yr) for S5 1044+71 based on Fermi…

Black Hole Explorer (BHEX) is a space VLBI mission concept, which can probe the black hole spacetime and the plasma properties including the magnetic fields of the accretion flows and relativistic jets. We propose science cases anticipated…

In the last 10 years multi-wavelength fast variability studies of low mass X-ray binaries have shown a dramatic development. A key discovery was the detection of O-IR sub-second fluctuations in two black-hole transients, lagging the X-rays…

Radio loud active galactic nuclei present a remarkable variety of signs indicating the presence of periodical processes possibly originating in binary systems of supermassive black holes, in which orbital motion and precession are…