Direct observation of an extended X-ray jet at z = 6.1

Abstract

We report on the direct observation of an extended X-ray jet in the z = 6.1 radio-loud active galactic nucleus PSO J030947.49+271757.31 from a deep Chandra X-ray observation (128 ksec). This detection represents the most distant kiloparsec-scale off-nuclear emission resolved in X-rays to date. The angular distance of the emission is ∼4″ (corresponding to ∼20 kpc at z = 6.1), along the same direction of the jet observed at parsec scales in previous VLBA high-resolution radio observations. Moreover, the 0.5–7.0 keV isophotes coincide with the extended radio emission as imaged by the VLA Sky Survey at 3 GHz. The rest-frame 2–10 keV luminosity of the extended component is L2 − 10 keV = 5.9 × 1044 erg s−1, about 8% of the core: this makes it one of the most luminous jets resolved in X-rays so far. Through spectral energy distribution modelling we find that this emission can be explained by the inverse Compton interaction with the photons of the cosmic microwave background, assuming that the jet’s physical parameters are similar to those in the local Universe. At the same time, we find that the radiation produced by a putative population of high-energy electrons through the synchrotron process observed at low redshift is quenched at high redshift, hence becoming negligible.

The [CII] and FIR properties ofz> 6 radio-loud quasars

“…A one-sided jet launched by this quasar points toward us at an angle smaller than 38 • based on high resolution observations with the Karl G. Jansky Very Large Array (VLA) at the National Radio Astronomy Observatory (NRAO, Spingola et al 2020). The jet is seen in the X-ray and it is extended across ∼4 or ∼20 kpc (Ighina et al 2022). The radio spectrum of J0309+2717 is flat with a spectral index α = −0.53 ± 0.02 at frequencies from 0.147 GHz to 8.2 GHz (see Fig.…”

The [CII] and FIR properties of z>6 radio-loud quasars

“…A one-sided jet launched by this quasar is pointing towards an observer at the angle smaller than 38 • based on high resolution observations with the Karl G. Jansky Very Large Array (VLA) of the National Radio Astronomy Observatory (NRAO, Spingola et al 2020). The jet is seen in X-ray and is extended across ∼ 4 or ∼ 20 kpc (Ighina et al 2022). The radio spectrum of J0309+2717 is flat with a spectral index α = −0.53 ± 0.02 at frequencies from 0.147 GHz to 8.2 GHz (see Fig.…”

“…The radio spectrum of J0309+2717 is flat with a spectral index α = −0.53 ± 0.02 at frequencies from 0.147 GHz to 8.2 GHz (see Fig. 3, Ighina et al 2022;Mufakharov et al 2020). J0309+2717 has the brightest 250 GHz continuum emission in our sample (F cont = 4.39 ± 0.15 mJy) and the second brightest [CII] line emission (F [CII] = 2.6 ± 0.2 Jy km s −1 ).…”

Milliarcsecond X-Ray Astrometry to Resolve Inner Regions of AGN at z > 1 Using Gravitational Lensing

“…The X-ray emission in jets is complex, as it involves several mechanisms (e.g., Schwartz et al 2000) and can be extended on several kpc (e.g., Schwartz et al 2020). At high redshift, studies of the X-ray properties of AGN are mostly limited to the brightest (>10 44 erg s −1 ) sources (e.g., Vito et al 2019;Ighina et al 2022;Snios et al 2021).…”