2014/12/05 by E. Eardley, J. A. Peacock, T. McNaught-Roberts +12 · 1 citation
Physics and Astronomy · #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stv237
15 pages, 15 figures
arxiv created 2014/12/05 · arxiv updated 2015/06/23
We investigate the dependence of the galaxy luminosity function on geometric environment within the Galaxy And Mass Assembly (GAMA) survey. The tidal tensor prescription, based on the Hessian of the pseudo-gravitational potential, is used to classify the cosmic web and define the geometric environments: for a given smoothing scale, we classify every position of the surveyed region, 0.04<z<0.26, as either a void, a sheet, a filament or a knot. We consider how to choose appropriate thresholds in the eigenvalues of the Hessian in order to partition the galaxies approximately evenly between environments. We find a significant variation in the luminosity function of galaxies between different geometric environments; the normalisation, characterised by ϕ* in a Schechter function fit, increases by an order of magnitude from voids to knots. The turnover magnitude, characterised by M^*, brightens by approximately 0.5 mag from voids to knots. However, we show that the observed modulation can be entirely attributed to the indirect local-density dependence. We therefore find no evidence of a direct influence of the cosmic web on the galaxy luminosity function.