Authors: Lee S. Kelvin, Simon P. Driver, Aaron S.G. Robotham, Alister W. Graham, Steven Phillipps, Nicola K. Agius, Mehmet Alpaslan, Ivan Baldry, Steven P. Bamford, Joss Bland-Hawthorn, Sarah Brough, Michael J.I. Brown, Matthew Colless, Christopher J. Conselice, Andrew M. Hopkins, Jochen Liske, Jon Loveday, Kevin A. Pimbblet, Cristina C. Popescu, Matthew Prescott, Edward N. Taylor, Richard J. Tuffs
Abstract: We report the morphological classification of 3727 galaxies from the Galaxy and Mass Assembly survey with Mr < -17.4 mag and in the redshift range 0.025 < z < 0.06 (2.1 x 105 Mpc3) into E, S0-Sa, SB0-SBa, Sab-Scd, SBab-SBcd, Sd-Irr and little blue spheroid classes. Approximately 70% of galaxies in our sample are disk dominated systems, with the remaining ~30% spheroid dominated. We establish the robustness of our classifications, and use them to derive morphological-type luminosity functions and luminosity densities in the ugrizYJHK passbands, improving on prior studies that split by global colour or light profile shape alone. We find that the total galaxy luminosity function is best described by a double-Schechter function while the constituent morphological-type luminosity functions are well described by a single-Schechter function.
These data are also used to derive the star-formation rate densities for each Hubble class, and the attenuated and unattenuated (corrected for dust) cosmic spectral energy distributions, i.e., the instantaneous energy production budget. While the observed optical/near-IR energy budget is dominated 58:42 by galaxies with a significant spheroidal component, the actual energy production rate is reversed, i.e., the combined disk dominated populations generate ~1.3 times as much energy as the spheroid dominated populations. On the grandest scale, this implies that chemical evolution in the local Universe is currently confined to mid-type spiral classes like our Milky Way.