Galaxy And Mass Assembly (GAMA): The galaxy stellar mass function at z < 0.06

TL;DR

This paper measures the galaxy stellar mass function at low redshift using GAMA survey data, providing a robust double Schechter function fit and confirming the upturn at low masses with implications for galaxy formation models.

Contribution

The study presents the first detailed low-redshift GSMF from GAMA, using a density-corrected method and confirming the low-mass upturn with multiple band data.

Findings

GSMF well described by a double Schechter function between 10^8 and 10^11.5 Msun.

The upturn in the GSMF is confirmed in i-band and K-band luminosity functions.

Robust measurement of the GSMF below 10^8 Msun within the GAMA volume.

Abstract

We determine the low-redshift field galaxy stellar mass function (GSMF) using an area of 143 deg^2 from the first three years of the Galaxy And Mass Assembly (GAMA) survey. The magnitude limits of this redshift survey are r < 19.4 mag over two thirds and 19.8 mag over one third of the area. The GSMF is determined from a sample of 5210 galaxies using a density-corrected maximum volume method. This efficiently overcomes the issue of fluctuations in the number density versus redshift. With H_0 = 70, the GSMF is well described between 10^8 and 10^11.5 Msun using a double Schechter function with mass^* = 10^10.66 Msun, phi_1^* = 3.96 x 10^-3 Mpc^-3, alpha_1 = -0.35, phi_2^* = 0.79 x 10^-3 Mpc^-3 and alpha_2 = -1.47. This result is more robust to uncertainties in the flow-model corrected redshifts than from the shallower Sloan Digital Sky Survey main sample (r < 17.8 mag). The upturn in the GSMF is also seen directly in the i-band and K-band galaxy luminosity functions. Accurately measuring the GSMF below 10^8 Msun is possible within the GAMA survey volume but as expected requires deeper imaging data to address the contribution from low surface-brightness galaxies.