Alma Reveals A Gas-rich, Maximum-starburst In The Hyperluminous, Dust-obscured Quasar W0533-3401 AT $z\sim2.9$

TL;DR

This study uses ALMA observations to analyze a hyperluminous, dust-obscured quasar at z~2.9, revealing it as a gas-rich, maximum-starburst galaxy with rapid black hole growth, indicating a transitional evolutionary phase.

Contribution

First detailed multiwavelength analysis of a hyperluminous dust-obscured quasar showing its gas-rich, starburst, and black hole growth properties, highlighting its transitional evolutionary stage.

Findings

W0533-3401 is gas-rich with M_gas=8.4×10^10 M_sun.

Star formation rate estimated between 3000-7000 M_sun/yr.

Black hole growth rate suggests rapid SMBH development.

Abstract

We present ALMA observations and multiwavelength spectral energy distribution (SED) analysis in a WISE-selected, hyperluminous dust-obscured quasar W0533-3401 at $z=2.9$. We derive its physical properties of each component, such as molecular gas, stars, dust and the central supermassive black hole (SMBH). Both the dust continuum at 3 mm and the CO(3-2) line are detected. The derived molecular gas mass $M_{\rm gas}=8.4\times10^{10}\ M_\odot$ and its fraction $f_{\rm gas}=0.7$ suggest that W0533-3401 is gas-rich. The star formation rate (SFR) has been estimated to be $\sim3000-7000\ M_\odot$ yr$^{-1}$ by using different methods. The high values of SFR and specific SFR suggest that W0533-3401 is a maximum-starburst. The corresponding gas depletion timescales are very short ($t_{\rm depl}\sim12-28$ Myr). The CO(3-2) emission line is marginally resolved and has a velocity gradient, which is possibly due to a rotating gas disk, gas outflow or merger. Finally, we infer the black hole mass growth rate of W0533-3401 (${\dot{M}}_{\rm BH}$ = 49 $M_\odot$ yr$^{-1}$), which suggests a rapid growth of the central SMBH. The observed black hole to stellar mass ratio $M_{\rm BH}/M_\star$ of W0533-3401, which is dependent on the adopted Eddington ratio, is over one order of magnitude higher than the local value, and is evolving towards the evolutionary trend of unobscured quasars. Our results are consistent with the scenario that \wobs, with both a gas-rich maximum-starburst and a rapid black hole growth, is experiencing a short transition phase towards an unobscured quasar.