Far infra-red emission lines in high redshift quasars

TL;DR

This paper reports high-redshift quasar observations revealing companion galaxies, rapid chemical evolution, and powerful quasar-driven outflows through far infra-red emission lines, advancing understanding of early galaxy and black hole co-evolution.

Contribution

It provides new high-resolution measurements of [CII], [NII], and CO lines in distant quasars, uncovering companion galaxies, metallicity levels, and extreme outflows not previously observed at such redshifts.

Findings

Detection of a companion galaxy near the quasar at z=4.4.

Evidence of rapid chemical evolution with near-solar metallicity.

Observation of the highest quasar-driven outflow rate to date (>3500 M_sun/yr).

Abstract

We present Plateau de Bure Interferometer observations of far infra-red emission lines in BRI 0952-0115, a lensed quasar at z=4.4 powered by a super-massive black hole (M_BH=2x10^9 M_sun). In this source, the resolved map of the [CII] emission at 158 micron allows us to reveal the presence of a companion galaxy, located at \sim 10 kpc from the quasar, undetected in optical observations. From the CO(5-4) emission line properties we infer a stellar mass M*<2.2x10^10 M_sun, which is significantly smaller than the one found in local galaxies hosting black holes with similar masses (M* \sim 10^12 M_sun). The detection of the [NII] emission at 205 micron suggests that the metallicity in BRI 0952-0115 is consistent with solar, implying that the chemical evolution has progressed very rapidly in this system. We also present PdBI observations of the [CII] emission line in SDSSJ1148+5251, one of the most distant quasar known, at z=6.4. We detect broad wings in the [CII] emission line, indicative of gas which is outflowing from the host galaxy. In particular, the extent of the wings, and the size of the [CII] emitting region associated to them, are indicative of a quasar-driven massive outflow with the highest outflow rate ever found (dM/dt>3500 M_sun/yr).