A radio structure resolved at the deca-parsec scale in the radio-quiet quasar PDS 456 with an extremely powerful X-ray outflow
Journal article, 2019

Active galactic nuclei (AGNs) accreting at rates close to the Eddington limit can host radiatively driven mildly relativistic outflows. Some of these X-ray absorbing but powerful outflows can produce strong shocks, resulting in a significant non-thermal emission. This outflow-driven radio emission might be detectable in the radio-quiet quasar PDS 456, as it has a bolometric luminosity that reaches the Eddington limit and a relativistic wide-aperture X-ray outflow with a kinetic power high enough to quench the star formation in its host galaxy. To investigate this possibility, we performed very-long-baseline interferometric (VLBI) observations of the quasar with the European VLBI Network (EVN) at 5 GHz. The full-resolution EVN image reveals two faint and diffuse radio components with a projected separation of about 20 pc and an average brightness temperature of around two million Kelvin. In relation to the optical submas-accuracy position measured by the Gaia mission, the two components are very likely on opposite sides of an undetected radio core. Thus, the VLBI structure at the deca-pc scale could be either a young jet or a bidirectional radio-emitting outflow, launched in the vicinity of a strongly accreting central engine. Two diffuse components at the hecto-pc scale, likely the relic radio emission from past AGN activity, are tentatively detected on each side in the low-resolution EVN image.

Quasars: individual: PDS 456

Galaxies: active

Radio continuum: galaxies


Jun Yang

Shanghai Astronomical Observatory

Chalmers, Space, Earth and Environment, Onsala Space Observatory, Onsala Space Observatory, Observation Support

Tao An

Shanghai Astronomical Observatory

Fang Zheng

Chinese Academy of Sciences

Shanghai Astronomical Observatory

Willem A. Baan

Netherlands Institute for Radio Astronomy (ASTRON)

Chinese Academy of Sciences

Z. Paragi

Joint Institute for VLBI in Europe (JIVE)

P. Mohan

Shanghai Astronomical Observatory

Z. L. Zhang

Shanghai Astronomical Observatory

Xiang Liu

Chinese Academy of Sciences

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 482 2 1701-1705

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Other Physics Topics



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