Galaxy and Mass Assembly (GAMA): Tracing galaxy environment using the marked correlation function

TL;DR

This study uses the GAMA survey to analyze how various galaxy properties like stellar mass and luminosity trace galaxy environments, revealing stellar mass as the best indicator and highlighting the impact of survey flux limits on clustering measurements.

Contribution

It demonstrates the effectiveness of stellar mass as a tracer of galaxy environment and examines how survey flux limits influence clustering analyses.

Findings

Stellar mass is the best tracer of galaxy environment.

K-band luminosity is a good proxy but misses close pairs of red galaxies.

Higher flux limits miss information about close starburst galaxy pairs.

Abstract

We investigate how different galaxy properties - luminosities in u, g, r, J, K-bands, stellar mass, star formation rate and specific star formation rate trace the environment in the local universe. We also study the effect of survey flux limits on galaxy clustering measurements. We measure the two-point correlation function (2pCF) and marked correlation functions (MCFs) using the aforementioned properties as marks. We use nearly stellar-mass-complete galaxy sample in the redshift range 0.1 < z < 0.16 from the Galaxy And Mass Assembly (GAMA) survey with a flux limit of r < 19.8. Further, we impose a brighter flux limit of r < 17.8 to our sample and repeat the measurements to study how this affects galaxy clustering analysis. We compare our results to measurements from the Sloan Digital Sky Survey (SDSS) with flux limits of r < 17.8 and r < 16.8. We show that the stellar mass is the best tracer of galaxy environment, the K-band luminosity being a good substitute, although such a proxy sample misses close pairs of evolved, red galaxies. We also confirm that the u-band luminosity is a good, but not a perfect proxy of star formation rate in the context of galaxy clustering. We observe an effect of the survey flux limit on clustering studies - samples with a higher flux limit (smaller magnitude) miss some information about close pairs of starburst galaxies.