1,128 datasets found

We present photographic UBV photometry of the blazar 3C 345 that were made during 79 nights in 1971-1974 and 1983-1984 as a part of the Petersburg Quasar Monitoring Program...

The location of {gamma}-ray-emitting region in blazars has been an open issue for several decades and is still being debated. We use the Paliya et al. sample of 619...

A two-component model of radio emission has been used to explain some radio observational properties of Active Galactic Nuclei (AGNs) and, in particular, of blazars. In this...

We present an analysis of CCD images (obtained at the Palomar 1.5m telescope) of more than 100 quasars; many of the objects have been or will be observed in the HST Key Project...

The question of radio dichotomy in active galactic nuclei (AGNs) is still in debate, even though it has been discussed for more than 40 years. In order to solve this old riddle,...

The extragalactic radio sources are divided into two subclasses (radio-loud and radio-quiet sources) in the literature using radio loudness (R), which is defined as the ratio of...

We construct a sample of X-ray-bright optically faint active galactic nuclei by combining Subaru Hyper Suprime-Cam, XMM-Newton, and infrared source catalogs. Fifty-three X-ray...

We studied the correlations of the flux of the broad-line emission (FBLR) with the X-ray emission flux, optical emission flux at 5500{AA} and radio emission flux at 5GHz,...

Black holes generate collimated, relativistic jets, which have been observed in {gamma}-ray bursts (GRBs), microquasars, and at the center of some galaxies [active galactic...

We present an optical spectroscopic atlas for 123 core-dominated radio-loud active galactic nuclei with relativistic jets, drawn from the MOJAVE/2cm (Monitoring of Jets in AGN...

Quasars are very important in materializing the reference frame. The excess emission of AGNs (active galactic nuclei) in the mid-infrared band can be used to identify quasar...

Quasars are essential for astrometric in the sense that they are spatial stationary because of their large distance from the Sun. The European Space Agency (ESA) space...

We study the {gamma}-ray luminosity and beaming effect for Fermi blazars. Our results are as follows. (i) There are significant correlations between {gamma}-ray luminosity and...

In this work, we report new quasars discovered in fields in the vicinity of the Andromeda (M31) and Triangulum (M33) galaxies with the Large Sky Area Multi-Object Fiber...

Observations suggest that gamma-ray loud blazars are strongly beamed. The Fermi mission has detected many of blazars, which provide us with a good opportunity to investigate the...

Fixes are presented to be applied to the Veron-Cetty and Veron (VCV) Quasar Catalogue, 13th edition (Cat. VII/258). These are comprised of 39 deduplicati ons, 380 astrometric...

We present a catalogue of the 322 damped Lyman alpha absorbers taken from the literature. All damped Lyman alpha absorbers are included, with no selection on redshift or quasar...

Bright quasars, powered by accretion onto billion-solar-mass black holes, already existed at the epoch of reionization, when the Universe was 0.5-1 billion years old. How these...

Theoretical models for the production of relativistic jets from active galactic nuclei predict that jet power arises from the spin and mass of the central supermassive black...

The Keck telescope's High Resolution Spectrograph (HIRES) has previously provided evidence for a smaller fine-structure constant, {alpha}, compared to the current laboratory...