# The H-alpha luminosity-dependent clustering of star-forming galaxies from z~0.8 to z~2.2 with HiZELS

## TL;DR

This study investigates how the clustering of star-forming galaxies, selected by H-alpha luminosity, evolves from redshift 0.8 to 2.2, revealing a strong link between galaxy star formation and dark matter halo environment.

## Contribution

It provides a detailed analysis of the clustering of star-forming galaxies across three redshifts and introduces a redshift-independent relation between H-alpha luminosity and dark matter halo mass.

## Key findings

- Clustering strength and bias increase with H-alpha luminosity at all redshifts.
- Typical galaxies reside in halos of a few times 10^12 solar masses.
- A tight, redshift-independent relation links H-alpha luminosity to halo mass.

## Abstract

We present clustering analyses of identically-selected star-forming galaxies in 3 narrow redshift slices (at z=0.8, z=1.47 and z=2.23), from HiZELS, a deep, near-infrared narrow-band survey. The HiZELS samples span the peak in the cosmic star-formation rate density, identifying typical star-forming galaxies at each epoch. Narrow-band samples have well-defined redshift distributions and are therefore ideal for clustering analyses. We quantify the clustering of the three samples, and of H-alpha luminosity-selected subsamples, initially using simple power law fits to the two-point correlation function. We extend this work to link the evolution of star-forming galaxies and their host dark matter halos over cosmic time using sophisticated dark matter halo models. We find that the clustering strength, r0, and the bias of galaxy populations relative to the clustering of dark matter increase linearly with H-alpha luminosity (and, by implication, star-formation rate) at all three redshifts, as do the host dark matter halo masses of the HiZELS galaxies. The typical galaxies in our samples are star-forming centrals, residing in halos of mass M_halo ~ a few times 10^12M_solar. We find a remarkably tight redshift-independent relation between the H-alpha luminosity scaled by the characteristic luminosity, L(H-alpha)/L(H-alpha)*(z), and the minimum host dark matter halo mass of central galaxies. This reveals that the dark matter halo environment is a strong driver of galaxy star-formation rate and therefore of the evolution of the star-formation rate density in the Universe.