1,348 datasets found

In addition to their great astrophysical interest, quasars represent quasi-ideal reference objects in the celestial sphere with, a priori, a lack of significant proper motion....

We present a catalog of quasars selected from broad-band photometric ugri data of the Kilo-Degree Survey Data Release 3 (KiDS DR3). The QSOs are identified by the random forest...

Few active galactic nuclei (AGN) reveal double-sided jet systems. However, these systems are crucial to understand basic physical properties of extragalactic jets. We address...

Very long baseline interferometry (VLBI) observations at 86 GHz (wavelength, {lambda}=3mm) reach a resolution of about 50{mu}as, probing the collimation and acceleration regions...

We present a study of the low-frequency radio properties of broad absorption line quasars (BALQSOs) from the LOFAR Two-metre Sky-Survey Data Release 1 (LDR1). The value-added...

Theoretical models of galaxy formation suggest that the presence of an active galactic nucleus (AGN) is required to regulate the growth of its host galaxy through feedback...

At the Universitaetssternwarte Bochum near Cerro Armazones we have monitored the Seyfert-1 galaxy 3C 120 between September 2014 and March 2015 in BVRI and a narrow band filter...

The well established negative correlation between the {alpha}OX spectral slope and the optical/UV luminosity, a by product of the relation between X-rays and optical/UV...

We present a multifrequency, dense radio monitoring program of the blazar OJ287 using the 100-m Effelsberg radio telescope. The program aims to test different binary...

Conventional radio surveys of deep fields ordinarily have arc-second scale resolutions often insufficient to reliably separate radio emission in distant galaxies originating...

We describe a catalogue of gamma-ray source candidates selected using the minimum spanning tree (MST) algorithm on the nine year Fermi-LAT sky (Pass 8) at energies higher than...

We quantify the temporal behaviour of the optical polarisation fraction and angle for a selected sample of radio-loud NLSy1s. We also search for rotations of the polarisation...

We present the result of our Allan standard deviation based classification according to their astrometric stability. The classification is divided into three categories (stable...

Redshifts are fundamental for our understanding of extragalactic X-ray sources. Ambiguous counterpart associations, expensive optical spectroscopy and/or multimission...

The energetic feedback that is generated by radio jets in active galactic nuclei (AGNs) has been suggested to be able to produce fast outflows of atomic hydrogen (HI) gas which...

We present the analysis of the rest-frame optical-to-UV spectrum of APM 08279+5255, a well-known lensed broad absorption line (BAL) quasar at z=3.911. The spectroscopic data are...

We investigate the physical structure of the active galactic nucleus (AGN) wind in the Seyfert-1 galaxy NGC 7469 through high-resolution X-ray spectroscopy with Chandra HETGS...

Many active galactic nuclei (AGN) and particularly narrow line Seyfert 1 (NLS1) galaxies, usually exhibit blueshifts and blue wings in several emission lines, which are mainly...

We present ALMA observations of the ^12^CO (2-1) line of the newly born (t_radio_~10^2^years) active galactic nucleus (AGN), PKS B1718-649. These observations reveal that the...

From an astrometric point of view, quasars constitute the best and almost ideal reference objects in the celestial sphere, with a priori no significant proper motion. Since the...