The highest redshift radio quasar as seen with the EVN and the VLA

Abstract

We report on European VLBI Network (EVN) and Very Large Array (VLA) observations of SDSS J0836+0054, the most distant radio-loud quasar known at present z=5.774). The source, with a total flux density of 1.1 mJy, shows a compact structure at 10 mas angular resolution at 1.6 GHz frequency, with no indication of multiple images produced by gravitational lensing within a 4x4 arcsec field above the brightness level of 100 microJy/beam. More recent 5 GHz EVN observations are being analysed now. As a by-product, a two-sided mas-scale jet structure is suspected in one of the phase-reference calibrator quasars, PKS 0837+012.