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Journal article
Placing LOFAR-detected quasars in C IV emission space: implications for winds, jets and star formation
Monthly notices of the Royal Astronomical Society, v 502(3), pp 4154-4169
23 Feb 2021
Abstract
We present an investigation of the low-frequency radio and ultraviolet properties of a sample of similar or equal to 10 500 quasars from the Sloan Digital Sky Survey Data Release 14, observed as part of the first data release of the Low-Frequency-Array Two-metre Sky Survey. The quasars have redshifts 1.5 < z < 3.5 and luminosities 44.6 < log(10) (L-bol/erg s(-1)) < 47.2. We employ ultraviolet spectral reconstructions based on an independent component analysis to parametrize the CIV lambda 1549-emission line that is used to infer the strength of accretion disc winds, and the HeII lambda 1640 line, an indicator of the soft X-ray flux. We find that radio-detected quasars are found in the same region of CIV blueshift versus equivalent-width space as radio-undetected quasars, but that the loudest, most luminous and largest radio sources exist preferentially at low CIV blueshifts. Additionally, the radio-detection fraction increases with blueshift whereas the radio-loud fraction decreases. In the radio-quiet population, we observe a range of HeII equivalent widths as well as a Baldwin effect with bolometric luminosity, whilst the radio-loud population has mostly strong HeII, consistent with a stronger soft X-ray flux. The presence of strong HeII is a necessary but not sufficient condition to detect radio-loud emission suggesting some degree of stochasticity in jet formation. Using energetic arguments and Monte Carlo simulations, we explore the plausibility of winds, compact jets, and star formation as sources of the radio quiet emission, ruling out none. The existence of quasars with similar ultraviolet properties but differing radio properties suggests, perhaps, that the radio and ultraviolet emission is tracing activity occurring on different time-scales.
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Details
- Title
- Placing LOFAR-detected quasars in C IV emission space: implications for winds, jets and star formation
- Creators
- Amy L. Rankine - University of CambridgeJames H. Matthews - University of CambridgePaul C. Hewett - University of CambridgeManda Banerji - University of CambridgeLeah K. Morabito - Durham UniversityGordon T. Richards - Drexel University
- Publication Details
- Monthly notices of the Royal Astronomical Society, v 502(3), pp 4154-4169
- Publisher
- Oxford Univ Press
- Number of pages
- 16
- Grant note
- University of Notre Dame SURF Co-operative New York University Universidad Nacional Autonoma de Mexico University of Utah Lawrence Berkeley National Laboratory; United States Department of Energy (DOE) Observatario Nacional/MCTI Science and Technology Facilities Council (STFC) studentship; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC) STFC via the Institute of Astronomy, Cambridge, Consolidated Grant MaxPlanck-Institut fur Astronomie (MPIA Heidelberg) Vanderbilt University Carnegie Institution for Science NWO; Netherlands Organization for Scientific Research (NWO) National Astronomical Observatories of China NOVA Chilean Participation Group CNRSINSU; Centre National de la Recherche Scientifique (CNRS) U.S. Department of Energy Office of Science; United States Department of Energy (DOE) Alfred P. Sloan Foundation Carnegie Mellon University Center for Astrophysics | Harvard Smithsonian United Kingdom Participation Group University of Washington University of Wisconsin Max-Planck-Institut fur Extraterrestrische Physik (MPE) Herchel Smith Fellowship at Cambridge University of Arizona Yale University New Mexico State University Pennsylvania State University University of Oxford Max-PlanckInstitut fur Astrophysik (MPA Garching) University of Portsmouth European Research Council; European Research Council (ERC); European Commission Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo Brazilian Participation Group French Participation Group The Johns Hopkins University; Johns Hopkins University Julich Supercomputing Centre Instituto de Astrof'isica de Canarias Ohio StateUniversity; Ohio State University University of Colorado Boulder University of Virginia UK Science and Technology Funding Council Leibniz Institut fur Astrophysik Potsdam (AIP) Shanghai Astronomical Observatory Korean Participation Group
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000767882200012
- Scopus ID
- 2-s2.0-85109841690
- Other Identifier
- 991019169501304721