2,844 datasets found

Wide area X-ray and far infrared surveys are a fundamental tool to investigate the link between AGN growth and star formation, especially in the low-redshift universe (z<1)....

The high energy spectrum of 3C 273 is usually understood in terms of inverse-Compton emission in a relativistic leptonic jet. This model predicts variability patterns and delays...

Deep optical surveys open the avenue for finding large numbers of BL Lac objects that are hard to identify because they lack the unique properties classifying them as such....

We propose new estimates of the secular aberration drift, mainly due to the rotation of the Solar System about the Galactic center, based on up-to-date VLBI observations and and...

We report the results obtained for the AGN Markarian 421 by model-fitting the data in the visibility plane, studing the proper motion of jet components, the light curve, and the...

We performed a kinematical analysis of the [CII] line emission of the BR 1202-0725 system at z~4.7 using ALMA science verification observations. The most prominent sources of...

We present results of long-term (1987-2010) optical spectral monitoring of the broad-line radio galaxy Arp 102B, a prototype of an active galactic nucleus with double-peaked...

1RXS J101015.9-311909 is a galaxy located at a redshift of z=0.14 hosting an active nucleus (called AGN) belonging to the class of bright BL Lac objects. Observations at high...

We report on the results of the first XMM-Newton systematic "excess variance" study of all the radio quiet, X-ray unobscured AGN. The entire sample consist of 161 sources...

195 polarimetric measurements of 182 BL Lac candidates from the SDSS taken with 3 different telescopes are presented. For each candidate the J2000 coordinates, its redshift,...

Recent studies have shown that a remarkable share of quasars classified in the literature as gigahertz-peaked spectrum (GPS) sources and high frequency peakers (HFPs) are...

We present a detailed X-ray spectral analysis of the sources in the 1Ms catalog of the Chandra Deep Field South (CDFS, J/ApJS/139/369) taking advantage of optical spectroscopy...

We propose a morphological classification based on the parsec scale structure of fifty-one High Frequency Peakers (HFPs) from the "bright" HFP sample. VLBA images at two...

2482 BVRI photometric data on eight red blazars taken from 3 Observatories in the period 2003 September - 2004 February are presented. A table is given, containing the source...

We present the completed results of a high resolution radio imaging survey of all (~200) low-luminosity active galactic nuclei (LLAGNs) and AGNs in the Palomar Spectroscopic...

We present the results of optical identification of 248 interplanetary scintillating (IPS) radio sources from the Pushchino Survey (PS) in the area of 0.11sr with the center at...

Spatially resolved CCD photometry of the Q2237+0305 gravitationally lensed quasar in V, R and I spectral bands from observations with the Maidanak 1.5-m telescope made in...

We use mid-infrared spectral decomposition to separate the 6{mu}m mid-infrared AGN continuum from the host emission in the ISO low resolution spectra of 71 active galaxies and...

Using the most recent (April 2003) version of the VLA FIRST survey radio catalog (Cat. ), we have searched for radio emission from >2800 AGN taken from the most recent (2001)...

We have observed 250 of the 258 southern sources in the complete 5GHz 1Jy sample by Kuehr et al. (1981, Cat. ) using the Australia Telescope Compact Array (ATCA) at 18.5GHz....