In order to determine the location of the gamma-ray emission site in blazars, we investigate
the time-domain relationship between their radio and gamma-ray emission. Light curves for …

We present 23 new VLBA images of the six established TeV blazars Markarian 421,
Markarian 501, H 1426+ 428, 1ES 1959+ 650, PKS 2155− 304, and 1ES 2344+ 514 …

We present results from four years of twice-weekly 15 GHz radio monitoring of about 1500
blazars with the Owens Valley Radio Observatory 40 m telescope. Using the intrinsic …

Context. To fully exploit the scientific potential of the Fermi mission for the physics of active
galactic nuclei (AGN), we initiated the F-GAMMA programme. Between 2007 and 2015 the F …

We use optical data from the Palomar Transient Factory (PTF) and the Catalina Real-Time
Transient Survey (CRTS) to study the variability of γ-ray-detected and non-detected objects …

ABSTRACT We present Very Long Baseline Array (VLBA) images of 20 TeV blazars not
previously well studied on the parsec scale. All 20 of these sources are high-frequency …

ABSTRACT The Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) was
released in 2010 February and the Fermi-LAT 2-Year Source Catalog (2FGL) appeared in …

We compare the variability properties of very high energy gamma-ray emitting BL Lac
objects in the optical and radio bands. We use variability information to distinguish multiple …

Context. Low-frequency radio arrays are opening a new window for the study of the sky, both
to study new phenomena and to better characterize known source classes. Being flat …

Context. With the advent of the Fermi Large Area Telescope (LAT) it was revealed that
blazars, representing the most extreme radio-loud active galactic nuclei (AGN) population …