A population of high-redshift type-2 quasars-II. Radio Properties

Abstract

We present multi-frequency radio observations of a sample of z~2 obscured (type-2) quasars in the Spitzer extragalactic First Look Survey area. We combine the public data at 1.4 GHz, used in the selection of these sources, with new observations at 610 MHz (GMRT) and at 4.9 GHz (VLA). We find the sample includes sources with steep, flat and gigahertz-peaked spectra. There are no strong correlations between the presence or absence of emission lines in the optical spectra and the radio spectral properties of the sample. However, there are no secure flat-spectrum type-2 quasars with narrow emission lines which would be problematic for unified schemes. Most of the population have straight radio spectra with spectral index alpha~1 as is expected for developed, potentially FRI-like, jets in which continous injection of relativistic electrons is accompanied by inverse-Compton losses against the cosmic microwave background.

arXiv comment6 pages, 2 colour figures, submitted to MNRAS

References in corpus (11)

• Obscured and unobscured active galactic nuclei in the Spitzer Space Telescope First Look Survey
• Deep Extragalactic X-ray Surveys
• The obscuration by dust of most of the growth of supermassive black holes
• Spitzer Detection of PAH and Silicate Dust Features in the Mid-Infrared Spectra of z~2 Ultraluminous Infrared Galaxies
• Spitzer Reveals Hidden Quasar Nuclei in Some Powerful FR II Radio Galaxies
• The optically-powerful quasar E1821+643 is associated with a 300-kpc scale FRI radio structure
• A population of high-redshift type-2 quasars-I. Selection Criteria and Optical Spectra
• Spitzer IRS spectroscopy of 3CR radio galaxies and quasars: Testing the unified schemes
• Redshifts from Spitzer Spectra for Optically Faint, Radio Selected Infrared Sources
• A Deep WSRT 1.4 GHz Radio Survey of the Spitzer Space Telescope FLSv Region
• The ISO-2MASS AGN survey: On the type-1 sources

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• Discovery of Radio Jets in z~2 ULIRGs with Deep 9.7um Silicate Absorption
• The prevalence of FRI radio quasars
• Millimetre observations of a sample of high-redshift obscured quasars
• Mid-infrared spectroscopy of high-redshift obscured quasars
• The radio core of the Ultraluminous Infrared Galaxy F00183-7111: watching the birth of a quasar
• An 80-kpc Lyman-alpha halo around a high redshift type-2 QSO
• Gas and dust in a z=2.8 obscured quasar
• The Subaru/XMM-Newton Deep Field - II. The 37 brightest radio sources
• High-redshift obscured quasars: radio emission at sub-kiloparsec scales
• Optical variability of radio-intermediate quasars
• The molecular gas content of ULIRG type 2 quasars at z < 1
• The radio properties of optically obscured Spitzer sources
• VLT-FORS2 optical imaging and spectroscopy of 9 luminous type 2 AGN at 0.3<z<0.6: I. Ionized gas nebulae
• High-Resolution Radio Observations of Five Optically Selected Type 2 Quasars
• ATLAS: Deep Radio Observations of Six Square Degrees