ALMA detections of CO emission in the most luminous, heavily dust-obscured quasars at z>3

TL;DR

This study uses ALMA to detect CO emission in three extremely luminous, dust-obscured quasars at high redshift, revealing their gas-rich nature, complex gas dynamics, and potential feedback processes.

Contribution

First ALMA observations of CO in hyper-luminous, dust-obscured quasars at z>3, showing gas-rich systems with signs of mergers and outflows supporting AGN feedback models.

Findings

Detected CO$(4-3)$ emission in all three quasars.

Derived molecular gas masses of $10^{10-11}$ M$_\odot$.

Observed complex velocity structures indicating mergers and outflows.

Abstract

We report the results of a pilot study of CO$(4-3)$ emission line of three {\it WISE}-selected hyper-luminous, dust-obscured quasars (QSOs) with sensitive ALMA Band 3 observations. These obscured QSOs with $L_{\rm bol}>10^{14}L_\odot$ are among the most luminous objects in the universe. All three QSO hosts are clearly detected both in continuum and in CO$(4-3)$ emission line. Based on CO$(4-3)$ emission line detection, we derive the molecular gas masses ($\sim 10^{10-11}$ M$_\odot$), suggesting that these QSOs are gas-rich systems. We find that three obscured QSOs in our sample follow the similar $L'_{\rm CO}- L_{\rm FIR}$ relation as unobscured QSOs at high redshifts. We also find the complex velocity structures of CO$(4-3)$ emission line, which provide the possible evidence for gas-rich merger in W0149+2350 and possible molecular outflow in W0220+0137 and W0410$-$0913. Massive molecular outflow can blow away the obscured interstellar medium (ISM) and make obscured QSOs evolve towards the UV/optical bright, unobscured phase. Our result is consistent with the popular AGN feedback scenario involving the co-evolution between the SMBH and host galaxy.