Speaker
Description
We present the discovery of a >66 kpc radio jet in the radio-loud quasar J1601+3102, residing at a spectroscopically confirmed redshift of z = 4.912. This makes it the largest projected radio jet known to date at such early times. Using the International LOFAR Telescope, two apparently unrelated "companion sources" have been spatially resolved into two radio lobes. Spectroscopic follow-up with Gemini North confirmed the redshift which allowed a physical size to be derived. Such large jets have been argued to be elusive due to the high inverse-Compton scattering losses in the Early Universe. From the Gemini/GNIRS rest-frame-UV spectrum, a black hole mass of 4.5 × 10^8 solar masses and Eddington luminosity ratio of 0.45 are derived. This black hole mass is relatively low compared to the known high-z quasar population. A high Eddington ratio is not immediately associated with stable jet launching either. Can powerful jets be launched from lower black hole masses? Is J1601+3102 an exception, or the tip of an iceberg of large jetted AGNs at high redshifts that we have been missing hitherto? With sensitive SKA-like instruments we can now start searching for these objects to better understand the formation and evolution of jetted radio sources in the Early Universe. This discovery would not have been possible without the ILT, highlighting the need for the next-generation of (low-frequency) radio telescopes.
