This review provides an overview of recent advances in multi-wavelength and multi-
messenger observations of blazars, the current status of theoretical models for blazar …

We analyze the parsec-scale jet kinematics from 2007 June to 2018 December of a sample
of γ-ray bright blazars monitored roughly monthly with the Very Long Baseline Array (VLBA) …

A black hole can launch a powerful relativistic jet after it tidally disrupts a star. If this jet
fortuitously aligns with our line of sight, the overall brightness is Doppler boosted by several …

Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is
extremely variable on various timescales,–. This variability seems mostly random, although …

The Gaia Galactic survey mission is designed and optimized to obtain astrometry,
photometry, and spectroscopy of nearly two billion stars in our Galaxy. Yet as an all-sky multi …

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 …

Supermassive black holes at the centre of active galactic nuclei power some of the most
luminous objects in the Universe. Typically, very-long-baseline interferometric observations …

In recent years, certain luminous extragalactic optical transients have been observed to last
only a few days. Their short observed duration implies a different powering mechanism from …

Optical observations of a sample of 12 γ-ray-bright blazars from four optical data archives—
American Association of Variable Star Observers, Small and Moderate Aperture Research …

Spinning black holes in the centres of galaxies can release powerful magnetised jets. When
the jets are observed at angles of less than a few degrees to the line-of-sight, they are called …