Galaxy and Mass Assembly (GAMA): maximum-likelihood determination of the luminosity function and its evolution

• Published in: Monthly notices of the Royal Astronomical Society Vol. 451; no. 2; pp. 1540 - 1552
• Main Authors: Loveday, J., Norberg, P., Baldry, I. K., Bland-Hawthorn, J., Brough, S., Brown, M. J. I., Driver, S. P., Kelvin, L. S., Phillipps, S.
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 01-08-2015
• Subjects: Assembly; Astronomy; Density; Evolution; Flux; Luminosity; Maximum likelihood method; Red shift; Star & galaxy formation; Symbols; galaxies: luminosity function, mass function; galaxies: evolution; galaxies: statistics
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stv1013

We describe modifications to the joint stepwise maximum-likelihood method of Cole in order to simultaneously fit the Galaxy and Mass Assembly II galaxy luminosity function (LF), corrected for radial density variations, and its evolution with redshift. The whole sample is reasonably well fitted with luminosity (Q
e) and density (P
e) evolution parameters Q
e, P
e ≈ 1.0, 1.0 but with significant degeneracies characterized by Q
e ≈ 1.4 − 0.4P
e. Blue galaxies exhibit larger luminosity density evolution than red galaxies, as expected. We present the evolution-corrected r-band LF for the whole sample and for blue and red subsamples, using both Petrosian and Sérsic magnitudes. Petrosian magnitudes miss a substantial fraction of the flux of de Vaucouleurs profile galaxies: the Sérsic LF is substantially higher than the Petrosian LF at the bright end.