AGN on the Beach

Jet formation and physics

The z=6.18 radio quasar CFHQS J142952+544717 under Chandra X-ray lens

Giulia Migliori

 Mo, 15:15 ! Livein  Palazzo Santa Chiarafor  15min

The search for jetted quasars at high redshift (z>5-6) is an active field with ground-breaking discoveries following each other. The existence of these objects is in fact a challenge for model of structure formation, as their radio power requires a very massive black hole, and represents an unique opportunity to investigate the formation and expansion of jets at cosmic dawn. Among the few known radio-loud quasars at z>6, CFHQS J142952+544717 is characterised by a moderate radio-loudness and an extremely high X-ray luminosity (>10^46 erg/s), as reported by eROSITA and XMM-Newton observations. VLBI observations showed a compact (<100 pc) but marginally resolved morphology and a brightness temperature (T_B~10^9 K) that does not support an aligned jet, hence disfavouring Doppler boosting as the reason of the high X-ray luminosity, and possibly pointing to an initial stage of its radio activity. Here, we present the results of a ~30 ksec Chandra observation that allowed us to perform the first X-ray study of J1429 at sub-arcsecond resolution.

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