Galaxy Environment
The environment of a galaxy can be a key factor in determining the evolution of galaxies. The environment of a galaxy is a multi-faceted property and can be quantified and interpreted in a large number of different ways depending on observations available and given science goal.
Partial List of Probes of Environment
- N-th Nearest Neighbour
- Fixed Aperture Measures
- Correlation Functions, power spectra, counts-in-cells
- Identifying Groups, Clusters, Filaments, Voids
- Complementary observations of local gas content etc.
Galaxy Halo Connection
One key perspective on environment is the galaxy-halo connection; how the dark matter halo that a galaxy is in affects its evolution and determines its properties.
Typically this requires assuming some knowledge of the underlying dark matter halo distribution, and then measuring some properties of the galaxy population and constraining what the relationship could be.
This can be probed in a number of ways:
- Galaxy number counts; the comoving number density of galaxies
- Galaxy-galaxy clustering; measuring the correlation function/power spectrum of galaxies, often in angular space
- Galaxy-galaxy lensing; measure the correlation between galaxies and the shear on background galaxies from gravitational lensing
Very broadly, measurements of clustering contain information about information about galaxy environment on small (~<1Mpc) scales, and information about cosmology on large (~>1Mpc) scales
Some broader notes about galaxy clustering and correlation functions: File:Clustering notes small PH.pdf
Examples of Work by Current or Former Group Members in this Area
Comparing Galaxy Clustering in Horizon-AGN Simulated Lightcone Mocks and VIDEO Observations
The clustering and bias of radio-selected AGN and star-forming galaxies in the COSMOS field
PKSB1740-517: An ALMA view of the cold gas feeding a distant interacting young radio galaxy
The environment and host haloes of the brightest z~6 Lyman-break galaxies
Environmental Quenching and Galactic Conformity in the Galaxy Cross-Correlation Signal
The galaxy-halo connection in the VIDEO Survey at 0.5<z<1.7
Tracing the neutral gas environments of young radio AGN with ASKAP
Evolution in the bias of faint radio sources to z ~ 2.2
Galaxy and Mass Assembly (GAMA): The evolution of bias in the radio source population to z ~ 1.5
Sample variance, source clustering and their influence on the counts of faint radio sources
The environments of hyperluminous infrared galaxies at 0.44<z<1.55