Where the Wild Things Are: Observational Constraints on Black Holes' Growth

TL;DR

This paper reviews recent observational findings on supermassive black hole growth and their relation to host galaxies, emphasizing the role of multi-wavelength surveys like COSMOS in understanding cosmic evolution.

Contribution

It highlights new observational constraints on black hole-galaxy scaling relations at high redshift using COSMOS data, advancing the understanding of black hole evolution.

Findings

Evidence for AGN 'downsizing' from X-ray surveys

New constraints on black hole-galaxy scaling at 1<z<2

Multi-wavelength data enhances understanding of black hole growth

Abstract

The physical and evolutionary relation between growing supermassive black holes (AGN) and host galaxies is currently the subject of intense research activity. Nevertheless, a deep theoretical understanding of such a relation is hampered by the unique multi-scale nature of the combined AGN-galaxy system, which defies any purely numerical, or semi-analytic approach. Various physical process active on different scales have signatures in different parts of the electromagnetic spectrum; thus, observations at different wavelengths and theoretical ideas all should contribute towards a "large dynamic range" view of the AGN phenomenon. As an example, I will focus in this review on two major recent observational results on the cosmic evolution of supermassive black holes, focusing on the novel contribution given to the field by the COSMOS survey. First of all, I will discuss the evidence for the so-called "downsizing" in the AGN population as derived from large X-ray surveys. I will then present new constraints on the evolution of the black hole-galaxy scaling relation at 1<z<2 derived by exploiting the full multi-wavelength coverage of the survey on a complete sample of ~90 type 1 AGN.