Gas reservoir of a hyper-luminous QSO at z=2.6

Abstract

Understanding the relationship between the formation and evolution of galaxies and their central super massive black holes (SMBH) is one of the main topics in extragalactic astrophysics. Links and feedback may reciprocally affect both black hole and galaxy growth. Observations of the CO line at redshifts of 2-4 are crucial to investigate the gas mass, star formation activity and accretion onto SMBHs, as well as the effect of AGN feedback. Potential correlations between AGN and host galaxy properties can be highlighted by observing extreme objects. Despite their luminosity, hyper-luminous QSOs at z=2-4 are still little studied at mm wavelengths. We targeted CO(3-2) in ULAS J1539+0557, an hyper-luminos QSO (Lbol> 10^48 erg/s) at z=2.658, selected through its unusual red colors in the UKIDSS Large Area Survey (ULAS). We find a molecular gas mass of 4.1+-0.8 10^10 Msun, and a gas fraction of 0.4-0.1, depending mostly on the assumed source inclination. We also find a robust lower limit to the star-formation rate (SFR=250-1600 Msun/yr) and star-formation efficiency (SFE=25-350 Lsun/(K km s-1 pc2) by comparing the observed optical-near-infrared spectral energy distribution with AGN and galaxy templates. The black hole gas consumption timescale, M(H_2)/dM(accretion)/dt, is ~160 Myr, similar or higher than the gas consumption timescale. The gas content and the star formation efficiency are similar to those of other high-luminosity, highly obscured QSOs, and at the lower end of the star-formation efficiency of unobscured QSOs, in line with predictions from AGN-galaxy co-evolutionary scenarios. Further measurements of the (sub)-mm continuum in this and similar sources are mandatory to obtain a robust observational picture of the AGN evolutionary sequence.

Submitted to A&A

References in corpus (3)

• A multi-transition HCN and HCO+ study of 12 nearby active galaxies: AGN versus SB environments
• The Blast Wave Model for AGN Feedback: Effects on AGN Obscuration
• CO(1-0) in z >/~ 4 Quasar Host Galaxies: No Evidence for Extended Molecular Gas Reservoirs

Cited by in corpus (10)

• The WISSH Quasars Project III. X-ray properties of hyper-luminous quasars
• The WISSH QSOs project IX. Cold gas content and environment of luminous QSOs at z~2.4-4.7
• The Discovery of Gas-Rich, Dusty Starbursts in Luminous Reddened Quasars at $z\sim 2.5$ with ALMA
• Heavy X-ray obscuration in the most-luminous galaxies discovered by WISE
• ALMA observations of cold molecular gas in AGN hosts at z~1.5 - Evidence of AGN feedback?
• Evidence for feedback in action from the molecular gas content in the z~1.6 outflowing QSO XID2028
• What produces the far-infrared/submm emission in the most luminous QSOs?
• Powerful winds in high-redshift obscured and red quasars
• Resolving the Interstellar Medium in Ultraluminous Infrared QSO Hosts with ALMA
• Remarkably high mass and high velocity dispersion of molecular gas associated with a regular, absorption-selected type-I quasar