Evidence of strong quasar feedback in the early Universe

TL;DR

This paper presents the detection of the most distant massive quasar-driven outflow at z=6.4189, providing evidence that quasar feedback was active in the early Universe and could rapidly quench star formation in massive galaxies.

Contribution

It reports the discovery of the earliest known massive outflow driven by a quasar, supporting models of early quasar feedback affecting galaxy evolution.

Findings

Detected broad wings in [CII] line indicating a massive outflow

Outflow rate exceeds 3500 solar masses per year

Outflow can quench star formation within a few million years

Abstract

Most theoretical models invoke quasar driven outflows to quench star formation in massive galaxies, this feedback mechanism is required to account for the population of old and passive galaxies observed in the local universe. The discovery of massive, old and passive galaxies at z=2, implies that such quasar feedback onto the host galaxy must have been at work very early on, close to the reionization epoch. We have observed the [CII]158um transition in SDSSJ114816.64+525150.3 that, at z=6.4189, is one of the most distant quasars known. We detect broad wings of the line tracing a quasar-driven massive outflow. This is the most distant massive outflow ever detected and is likely tracing the long sought quasar feedback, already at work in the early Universe. The outflow is marginally resolved on scales of about 16 kpc, implying that the outflow can really affect the whole galaxy, as required by quasar feedback models. The inferred outflow rate, dM/dt > 3500 Msun/yr, is the highest ever found. At this rate the outflow can clean the gas in the host galaxy, and therefore quench star formation, in a few million years.