Galaxy And Mass Assembly (GAMA): The galaxy stellar mass function to $z=0.1$ from the r-band selected equatorial regions

Wright, AH and Robotham, ASG and Driver, SP and Alpaslan, M and Andrews, SK and Baldry, IK and Brough, JB-HS and Brown, MJI and Colless, M and Cunha, ED and Davies, LJM and Graham, AW and Holwerda, BW and Hopkins, AM and Kafle, PR and Kelvin, LS and Loveday, J and Maddox, SJ and Meyer, MJ and Moffett, AJ and Norberg, P and Phillipps, S and Rowlands, K and Taylor, EN and Wang, L and Wilkins, SM (2017) Galaxy And Mass Assembly (GAMA): The galaxy stellar mass function to $z=0.1$ from the r-band selected equatorial regions. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711

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Abstract

We derive the low redshift galaxy stellar mass function (GSMF), inclusive of dust corrections, for the equatorial Galaxy And Mass Assembly (GAMA) dataset covering 180 deg$^2$. We construct the mass function using a density-corrected maximum volume method, using masses corrected for the impact of optically thick and thin dust. We explore the galactic bivariate brightness plane ($M_\star-\mu$), demonstrating that surface brightness effects do not systematically bias our mass function measurement above 10$^{7.5}$ M$_{\odot}$. The galaxy distribution in the $M-\mu$-plane appears well bounded, indicating that no substantial population of massive but diffuse or highly compact galaxies are systematically missed due to the GAMA selection criteria. The GSMF is {fit with} a double Schechter function, with $\mathcal M^\star=10^{10.78\pm0.01\pm0.20}M_\odot$, $\phi^\star_1=(2.93\pm0.40)\times10^{-3}h_{70}^3$Mpc$^{-3}$, $\alpha_1=-0.62\pm0.03\pm0.15$, $\phi^\star_2=(0.63\pm0.10)\times10^{-3}h_{70}^3$Mpc$^{-3}$, and $\alpha_2=-1.50\pm0.01\pm0.15$. We find the equivalent faint end slope as previously estimated using the GAMA-I sample, although we find a higher value of $\mathcal M^\star$. Using the full GAMA-II sample, we are able to fit the mass function to masses as low as $10^{7.5}$ $M_\odot$, and assess limits to $10^{6.5}$ $M_\odot$. Combining GAMA-II with data from G10-COSMOS we are able to comment qualitatively on the shape of the GSMF down to masses as low as $10^{6}$ $M_\odot$. Beyond the well known upturn seen in the GSMF at $10^{9.5}$ the distribution appears to maintain a single power-law slope from $10^9$ to $10^{6.5}$. We calculate the stellar mass density parameter given our best-estimate GSMF, finding $\Omega_\star= 1.66^{+0.24}_{-0.23}\pm0.97 h^{-1}_{70} \times 10^{-3}$, inclusive of random and systematic uncertainties.

Item Type: Article This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. astro-ph.GA; astro-ph.GA Q Science > QB AstronomyQ Science > QC Physics Astrophysics Research Institute Oxford University Press Author 16 May 2017 11:39 06 Sep 2017 20:55 10.1093/mnras/stx1149 http://researchonline.ljmu.ac.uk/id/eprint/6434