Abstract The Event Horizon Telescope (EHT) Collaboration recently published the first
images of the supermassive black holes in the cores of the Messier 87 and Milky Way …

The recent hint of correlated γ-ray and neutrino emission from the blazar TXS 0506+ 056
has renewed interest in blazars as the source of high-energy neutrinos, in which the …

Powerful relativistic jets are one of the ubiquitous features of accreting black holes in all
scales,–. GRS 1915+ 105 is a well-known fast-spinning black-hole X-ray binary with a …

In this work, we report the presence of rapid intra-night optical variations in both flux and
polarization of the blazar BL Lacertae during its unprecedented 2020–2021 high state of …

We present periodicity search analyses on the γ-ray light curve of the TeV blazar PKS 1510-
089 observed by the Fermi Large Area Telescope. We report the detection of two transient …

We report the detection of several quasiperiodicities around 0.6–2.5 days in the optical
emission of the blazar S4 0954+ 658. The source was observed by the Transiting Exoplanet …

Context. The detection of quasi-periodic oscillations (QPOs) in the light curves of active
galactic nuclei (AGNs) can provide insights into the physics of the super-massive black …

We present a long term optical R band light-curve analysis of the gravitationally lensed
blazar AO 0235+ 164 in the time span 1982–2019. Several methods of analysis lead to the …

We analyze the quasiperiodic oscillation (QPO) of the historical light curve of flat-spectrum
radio quasars PKS 0405-385 detected by the Fermi Large Area Telescope from 2008 …

Variability is a typical observation feature of Fermi blazars, which sometimes shows quasi-
periodic oscillation (QPO). In this work, we obtain 5 day binned light curves (with a time …