An ultra-luminous quasar at z=5.363 with a ten billion solar mass black hole and a Metal-Rich DLA at z~5

TL;DR

This paper reports the discovery of an ultra-luminous quasar at redshift 5.363 hosting a supermassive black hole of over ten billion solar masses, along with a metal-rich Damped Lyα system, providing insights into early universe black hole growth and galaxy evolution.

Contribution

The discovery of one of the most luminous quasars at high redshift and a metal-rich DLA offers new constraints on quasar luminosity and black hole mass functions in the early universe.

Findings

Quasar hosts a SMBH of approximately 10 billion solar masses.

The quasar's luminosity is among the highest at its redshift.

Detection of a metal-rich DLA at z~5 in the quasar spectrum.

Abstract

We report the discovery of an ultra-luminous quasar J030642.51+185315.8 (hereafter J0306+1853) at redshift 5.363, which hosts a super-massive black hole (SMBH) with $M_{BH} = (1.07 \pm 0.27) \times10^{10}~M_\odot$. With an absolute magnitude $M_{1450}=-28.92$ and bolometric luminosity $L_{bol}\sim3.4\times10^{14} L_{\odot}$, J0306+1853 is one of the most luminous objects in the early Universe. It is not likely to be a beamed source based on its small flux variability, low radio loudness and normal broad emission lines. In addition, a $z=4.986$ Damped Ly$\alpha$ system (DLA) with $\rm [M/H]=-1.3\pm0.1$, among the most metal rich DLAs at $z \gtrsim 5$, is detected in the absorption spectrum of this quasar. This ultra-luminous quasar puts strong constraint on the bright-end of quasar luminosity function and massive-end of black hole mass function. It will provide a unique laboratory to the study of BH growth and the co-evolution between BH and host galaxy with multi-wavelength follow-up observations. The future high resolution spectra will give more insights to the DLA and other absorption systems along the line-of-sight of J0306+1853.