We investigate the mean star formation rates (SFRs) in the host galaxies of∼ 3000 optically
selected quasi-stellar objects (QSOs) from the Sloan Digital Sky Survey within the Herschel-
ATLAS fields, and a radio-luminous subsample covering the redshift range of z= 0.2–2.5.
Using Wide-field Infrared Survey Explorer (WISE) and Herschel photometry (12–500 μm) we
construct composite spectral energy distributions (SEDs) in bins of redshift and active
galactic nucleus (AGN) luminosity. We perform SED fitting to measure the mean infrared�…

We characterize the contribution from accreted material to the galactic discs of the Auriga
Project, a set of high-resolution magnetohydrodynamic cosmological simulations of late-type
galaxies performed with the moving-mesh code arepo. Our goal is to explore whether a
significant accreted (or ex situ) stellar component in the Milky Way disc could be hidden
within the near-circular orbit population, which is strongly dominated by stars born in situ.
One-third of our models shows a significant ex situ disc but this fraction would be larger if�…

We report on long-term multiwavelength monitoring of blazar Mrk 421 by the GLAST-AGILE
Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and
Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour
in the period 2007–2015, characterized by several extreme flares. The ratio between the
optical, X-ray and γ-ray fluxes is very variable. The γ-ray flux variations show a fair
correlation with the optical ones starting from 2012. We analyse spectropolarimetric data�…