# Relativistic X-ray jets at high redshift

## TL;DR

This paper investigates high-redshift relativistic X-ray jets from quasars, highlighting how inverse Compton scattering off the cosmic microwave background becomes dominant at large redshifts, with Chandra observations revealing extended X-ray emission.

## Contribution

It presents the first Chandra survey of z>3 radio sources, demonstrating extended X-ray jets beyond radio emission in some high-redshift quasars, emphasizing the impact of the CMB on jet emission.

## Key findings

- Extended X-ray jets observed beyond radio jets in some high-z sources
- Inverse Compton scattering dominates electron energy loss at high redshift
- CMB energy density significantly influences jet X-ray emission at z>3

## Abstract

Powerful radio sources and quasars emit relativistic jets of plasma and magnetic fields that travel hundreds of kilo-parsecs, ultimately depositing energy into the intra- or inter-cluster medium. In the rest frame of the jet, the energy density of the cosmic microwave background is enhanced by the bulk Lorentz factor squared, and when this exceeds the magnetic energy density the primary loss mechanism of the relativistic electrons is via inverse Compton scattering. The microwave energy density is also enhanced by a factor (1+z)^4, which becomes important at large redshifts. We are using Chandra to survey a z>3 sub-sample of radio sources selected with 21 cm wavelength flux density > 70 mJy, and with a spectroscopic redshift. Out of the first 12 objects observed, there are two clear cases of the X-rays extending beyond the detectable radio jet.