The growth of typical star-forming galaxies and their supermassive black holes across cosmic time since z ∼ 2
Abstract
Understanding galaxy formation and evolution requires studying the interplay between the growth of galaxies and the growth of their black holes across cosmic time. Here, we explore a sample of Hα-selected star-forming galaxies from the High Redshift Emission Line Survey and use the wealth of multiwavelength data in the Cosmic Evolution Survey field (X-rays, far-infrared and radio) to study the relative growth rates between typical galaxies and their central supermassive black holes, from z = 2.23 to z = 0. Typical star-forming galaxies at z ∼ 1-2 have black hole accretion rates (dot{M}_BH) of 0.001-0.01 M⊙ yr-1 and star formation rates (SFRs) of ∼10-40 M⊙ yr-1, and thus grow their stellar mass much quicker than their black hole mass (3.3±0.2 orders of magnitude faster). However, ∼3 per cent of the sample (the sources detected directly in the X-rays) show a significantly quicker growth of the black hole mass (up to 1.5 orders of magnitude quicker growth than the typical sources). dot{M}_BH falls from z = 2.23 to z = 0, with the decline resembling that of SFR density or the typical SFR (SFR*). We find that the average black hole to galaxy growth (dot{M}_BH/SFR) is approximately constant for star-forming galaxies in the last 11 Gyr. The relatively constant dot{M}_BH/SFR suggests that these two quantities evolve equivalently through cosmic time and with practically no delay between the two.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2017
- DOI:
- 10.1093/mnras/stw2295
- arXiv:
- arXiv:1609.03571
- Bibcode:
- 2017MNRAS.464..303C
- Keywords:
-
- galaxies: evolution;
- galaxies: high-redshift;
- galaxies: star formation;
- cosmology: observations;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 10 pages, 8 figures, accepted to MNRAS