1,286 datasets found

We discuss whether modern machine learning methods can be used to characterize the physical nature of the large number of objects sampled by the modern multi-band digital...

By statistically analysing a large sample that includes Fermi-detected blazars (FBs) and non-Fermi-detected blazars (NFBs), we find that there are significant differences...

The ionizing continuum from active galactic nuclei is fundamental for interpreting their broad emission lines and understanding their impact on the surrounding gas. Furthermore,...

We present a study of extended galaxy halo gas through HI and OVI absorption over two decades in projected distance at z~0.2. The study is based on a sample of 95 galaxies from...

We obtain a sample of 87 radio-loud quasi-stellar objects (QSOs) in the redshift range 3.6<=z<=4.4 by cross-correlating sources in the Faint Images of the Radio Sky at...

We present the colour indices V-R of BL Lacertae object PKS 0537-441 on the basis of the photometric data monitored by the Rapid Eye Mounting (REM) telescope located at the ESO...

There is a large diversity in the CIV broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the CIV BAL...

Quasar damped Ly{alpha} (DLA) absorption-line systems with redshifts z<1.65 are used to trace neutral gas over approximately 70 percent of the most recent history of the...

In a single optical spectrum, the quasar narrow-line region (NLR) reveals low density, photoionized gas in the host galaxy interstellar medium, while the immediate vicinity of...

We present photometric and spectroscopic measurements of 53 QSO-galaxy pairs from the Sloan Digital Sky Survey (SDSS), where nebular emission lines from a 0<z<0.84...

This paper presents an absorption-line study of the multiphase circumgalactic medium (CGM) based on observations of Ly{alpha}, CII, CIV, SiII, SiIII, and SiIV absorption...

We present spectra of 163 quasars at z_em_>4.4 taken with the Gemini Multi Object Spectrometers, the largest publicly available sample of high-quality (signal-to-noise ratio...

We report here a study of nitrogen and {alpha}-capture element (O, S, and Si) abundances in 18 damped Ly{alpha} absorbers (DLAs) and sub-DLAs drawn from the European Southern...

Studies of radio-loud (RL) broad absorption line (BAL) quasars indicate that popular orientation-based BAL models fail to account for all observations. Are these results...

We present the results of a survey for CaII {lambda}{lambda}3934,3969 absorption-line systems culled from ~95000 Sloan Digital Sky Survey (SDSS) Data Release 7 and Data Release...

We present the results from an X-ray spectral analysis of active galactic nuclei (AGN) in the Chandra Deep Field-South, All-wavelength Extended Groth-strip International Survey...

We have obtained the rotation measures (RMs) of 2642 quasars by using cross-identification of the most updated quasar catalogue and the RM catalogue. After discounting the...

We present first results from RoboPol, a novel-design optical polarimeter operating at the Skinakas Observatory in Crete. The data, taken during the 2013 May-June commissioning...

The exact location of the {gamma}-ray emitting region in blazars is still controversial. In order to attack this problem we present first results of a cross-correlation analysis...

We study the environments of low-redshift (z<0.5) quasars based on a large and homogeneous data set from the Stripe 82 region of the Sloan Digital Sky Survey (SDSS). We have...