Exploring the high-redshift Universe
The growth of typical star-forming galaxies and their super massive black holes across cosmic time since z~2
Joao Calhau
Lancaster University
Understanding galaxy formation and evolution requires studying the interplay between the growth of galaxies and the growth of their black holes (BH) across cosmic time. Here we explore a sample of Halpha-selected star-forming galaxies from the HiZELS survey and use the wealth of multi-wavelength data in COSMOS (X-rays, far-infrared and radio) to study the relative growth between typical galaxies and their black holes, from z=2.23 to z=0.4. We find that the relative black hole to galaxy growth is approximately constant for star-forming galaxies since z=2.23, and that the black hole accretion rates typically fall from high to low redshift following the decline in star formation rate density. Typical star forming galaxies at z~1-2 have BH accretion rates of ~10^(-2) Msolar/yr, and thus grow their stellar mass much quicker than their BH mass (3-3.5 orders of magnitude faster). However, ~2% of the sample (the sources detected directly in the X-ray band) show a significantly quicker growth of the BH mass (up to 1.5 orders of magnitude quicker growth than the non-detected samples). Such relatively short but intense periods of growth likely play an important role in establishing the local M-sigma relation.


16:30 - 18:00
EX - LT2 (200)