Fast-Growing SMBHs in Fast-Growing Galaxies, at High Redshifts: The Role of Major Mergers As Revealed by ALMA

Frontiers in Astronomy and Space Sciences

Shemmer, Ohad¹  Lira, Paulina²  Trakhtenbrot, Benny³  Cicone, Claudia³  Maiolino, Roberto⁴  Netzer, Hagai⁵ 

[1] Cavendish Laboratory, University of Cambridge, United Kingdom;Departamento de Astronomia, Universidad de Chile, Chile;Department of Physics, Switzerland;INAF-Osservatorio Astronomico di Brera, Italy;Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy and the Wise Observatory, Tel-Aviv University, Israel

关键词: sub-millimetre galaxies;    Galaxy mergers;    Quasars: supermassive black holes;    Quasars: host galaxies;    high-redshift galaxies;   

DOI  :  10.3389/fspas.2017.00049

学科分类：空间科学

来源: Frontiers

【 摘 要 】

We present a long-term, multi-wavelength project to understand the epoch of fastest growth of the most massive black holes by using a sample of 40 luminous quasars at z~4.8. These quasars have rather uniform properties, with typical accretion rates and black hole masses of L/L_Edd~0.7 and M_BH~10^9 M_sun. The sample consists of ``FIR-bright'' sources with a previous Herschel/SPIRE detection, suggesting SFR>1000 M_sun/yr, as well as of ``FIR-faint'' sources for which Herschel stacking analysis implies a typical SFR of ~400 M_sun/yr. Six of the quasars have been observed by ALMA in [C II] 157.74 micron line emission and adjacent rest-frame ~150 □micron continuum, to study the dusty cold ISM. ALMA detected companion, spectroscopically confirmed sub-mm galaxies (SMGs) for three sources – one FIR-bright and two FIR-faint. The companions are separated by ~14-45 kpc from the quasar hosts, and we interpret them as major galaxy interactions. Our ALMA data therefore clearly support the idea that major mergers may be important drivers for rapid, early SMBH growth. However, the fact that not all high-SFR quasar hosts are accompanied by interacting SMGs, and their ordered gas kinematics observed by ALMA, suggest that other processes may be fueling these systems. Our analysis thus demonstrates the diversity of host galaxy properties and gas accretion mechanisms associated with early and rapid SMBH growth.

【 授权许可】

CC BY