BL Lac objects are active nuclei, hosted in massive elliptical galaxies, the emission of which
is dominated by a relativistic jet closely aligned with the line of sight. This implies the …

ABSTRACT The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on
2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in …

We present time-resolved broadband observations of the quasar 3C 279 obtained from multi-
wavelength campaigns conducted during the first two years of the Fermi Gamma-ray Space …

Diffusive shock acceleration (DSA) at relativistic shocks is widely thought to be an important
acceleration mechanism in various astrophysical jet sources, including radio-loud active …

Locating the gamma-ray emission sites in blazar jets is a long standing and highly
controversial issue. We jointly investigate several constraints on the distance scale r and …

We have been using the 0.76 m Katzman Automatic Imaging Telescope (KAIT) at Lick
Observatory to optically monitor a sample of 157 blazars that are bright in gamma-rays being …

I present a systematic study of gamma-ray flares in blazars. For this purpose, I propose a
very simple and practical definition of a flare as a period of time, associated with a given flux …

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 collect a large sample with a reliable redshift detected by the Fermi satellite after 10 yr of
data (4FGL-DR2), including blazars, gamma-ray narrow-line Seyfert 1 galaxies (γNLS1s) …

We present time series analyses of three-decade long radio observations of the BL Lacertae
object AO 0235+ 164 made at the University of Michigan Radio Astronomical Observatory …