Physical properties of the highest redshift supermassive black holes
Abstract
I will review the current understanding of key physical properties of some of the first generation of growing supermassive black holes (SMBHs). This includes their accretion rates and history, their host galaxies, and the large-scale environments that enabled their emergence about a billion years after the big bang. The available multi-wavelength data show that these SMBHs are consistent with Eddington-limited, radiatively efficient accretion that had to proceed almost continuously since very early epochs. New ALMA data confirms high SFRs and gas content in the host galaxies, and moreover a high fraction of companion, interacting galaxies, separated by 10-50 kpc. This clearly supports the idea that the first generation of luminous SMBHs grew in overdense environments, and that major mergers are important drivers for rapid early SMBH and host galaxy growth, although other fueling processes and accretion modes may still be required. Current X-ray surveys cannot access the lower-mass counterparts of these rare massive quasars, which would elucidate the earliest stages of BH formation and growth. Such low-mass nuclear BHs will be the prime targets of the deepest surveys foreseen for the next generation of X-ray space observatories, such as the upcoming ESA Athena mission and the NASA Lynx mission concept.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E3420T