Fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation

Abstract

A minority of the optically selected quasar population are red at optical wavelengths due to the presence of dust along the line-of-sight. A key focus of many red quasar studies is to understand their relationship with the overall quasar population: are they blue quasars observed at a (slight) inclination angle or do they represent a transitional phase in the evolution of quasars? Identifying fundamental differences between red and blue quasars is key to discriminate between these two paradigms. To robustly explore this, we have uniformly selected quasars from the Sloan Digital Sky Survey with mid-infrared counterparts, carefully controlling for luminosity and redshift effects. We take a novel approach to distinguish between colour-selected quasars in the redshift range of $0.2<z<2.4$ by constructing redshift-sensitive $g^{\ast }-i^{\ast }$ colour cuts. From cross-matching this sample to the Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey, we have found a factor $\approx$ 3 larger fraction of radio-detected red quasars with respect to that of blue quasars. Through a visual inspection of the FIRST images and an assessment of the radio luminosities (rest-frame $L_{1.4\mathrm{GHz}}$ and $L_{1.4\mathrm{GHz}}/L_{6\mu \mathrm{m}}$) we find that the radio-detection excess for red quasars is primarily due to compact and radio-faint systems (around the radio quiet--radio loud threshold). We show that our results rule out orientation as the origin for the differences between red and blue quasars and argue that they provide broad agreement with an evolutionary model.

Accepted to be published in MNRAS: 21 pages, 16 figures, and 6 tables

References in corpus (25)

• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• A Catalog of Quasar Properties from SDSS DR7
• Clustering of High Redshift ($z\ge 2.9$) Quasars from the Sloan Digital Sky Survey
• The Last of FIRST: The Final Catalog and Source Identifications
• Synchrotron Self-Compton Analysis of TeV X-ray Selected BL Lacertae Objects
• Evidence for Quasar Activity Triggered by Galaxy Mergers in HST Observations of Dust-reddened Quasars
• Signals from the Noise: Image Stacking for Quasars in the FIRST Survey
• Gamma-Ray Studies of Blazars: Synchro-Compton Analysis of Flat Spectrum Radio Quasars
• A Unified Catalog of Radio Objects Detected by NVSS, FIRST, WENSS, GB6, and SDSS
• Black-Hole Mass and Growth Rate at High Redshift
• The FIRST-2MASS Red Quasar Survey
• Radio Jets in Galaxies with Actively Accreting Black Holes: new insights from the SDSS
• Spitzer Observations of Young Red Quasars
• The Discovery of Gas-Rich, Dusty Starbursts in Luminous Reddened Quasars at $z\sim 2.5$ with ALMA
• Galaxy gas as obscurer: I. GRBs x-ray galaxies and find a N_H ~ M* relation
• Correlations of Quasar Optical Spectra with Radio Morphology
• Mean and Extreme Radio Properties of Quasars and the Origin of Radio Emission
• Are red 2MASS QSOs young?
• Relation between winds and jets in radio-loud AGN
• The nature of the intranight variability of radio-quiet quasars
• The B3-VLA CSS sample. VII: WSRT Polarisation Observations and the Ambient Faraday Medium Properties Revisited
• The Reddest DR3 SDSS/XMM Quasars
• Peering through the dust II: $XMM-Newton$ observations of two additional FIRST-2MASS red quasars
• Optical spectroscopic classification of a selection of Southern Hemisphere Fermi-LAT unclassified blazars
• Properties of spectrally-defined red QSOs at z = 0.3-1.2

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