A multi-wavelength continuum characterization of high-redshift broad absorption line quasars

Abstract

We present the results of a multi-wavelength study of a sample of high-redshift Radio Loud (RL) Broad Absorption Line (BAL) quasars. This way we extend to higher redshift previous studies on the radio properties, and broadband optical colors of these objects. We have se- lected a sample of 22 RL BAL quasars with 3.6 z 4.8 cross-correlating the FIRST radio survey with the SDSS. Flux densities between 1.25 and 9.5 GHz have been collected with the JVLA and Effelsberg-100m telescopes for 15 BAL and 14 non-BAL quasars used as compar- ison sample. We determine the synchrotron peak frequency, constraining their age. A large number of GigaHertz Peaked Spectrum (GPS) and High Frequency Peakers (HFP) sources has been found in both samples (80% for BAL and 71% for non-BAL QSOs), not suggesting a younger age for BAL quasars. The spectral index distribution provides information about the orientation of these sources, and we find statistically similar distributions for the BAL and non-BAL quasars in contrast to work done on lower redshift samples. Our sample may be too small to convincingly find the same effect, or might represent a real evolutionary effect based on the large fraction of young sources. We also study the properties of broadband colors in both optical (SDSS) and near- and mid-infrared (UKIDSS and WISE) bands, finding that also at high redshift BAL quasars tend to be optically redder than non-BAL quasars. However, these differences are no more evident at longer wavelength, when comparing colors of the two samples by mean of the WISE survey.

Accepted for publication on MNRAS, 2017 February 6. 14 pages, 10 figures

References in corpus (15)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• A Catalog of Broad Absorption Line Quasars in Sloan Digital Sky Survey Data Release 5
• The Radio-Loud Fraction of Quasars is a Strong Function of Redshift and Optical Luminosity
• The Intrinsic Fraction of Broad Absorption Line Quasars
• Outflows and the Physical Properties of Quasars
• Mining for Dust in Type 1 Quasars
• Radio Through X-ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars
• First 3 mm-VLBI imaging of the two-sided jet in Cygnus A. Zooming into the launching region
• Radio spectra and polarisation properties of radio-loud Broad Absorption Line Quasars
• Evolutive Unification in Composite Active Galactic Nuclei
• Use of neural networks for the identification of new z>=3.6 QSOs from FIRST-SDSS DR5
• Neural-network selection of high-redshift radio quasars, and the luminosity function at z~4
• Investigating the radio-loud phase of broad absorption line quasars
• Radio-Loud and Radio-Quiet BAL Quasars: A Detailed Ultraviolet Comparison

Cited by in corpus (5)

• Stratified disc wind models for the AGN broad-line region: ultraviolet, optical and X-ray properties
• A discovery of young radio sources in the cores of giant radio galaxies selected at hard X-rays
• Appearance vs Disappearance of broad absorption line troughs in quasars
• Fraction of broad absorption line quasars in different radio morphologies
• A Giant Metrewave Radio Telescope Survey of Radio-loud Broad Absorption Line Quasars