The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: evolution of higher-order correlations demonstrated with Minkowski functionals

Date Published:

May 01, 2019


We probe the higher-order galaxy clustering in the final data release ofthe Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey(BOSS) using germ-grain Minkowski functionals (MFs). Our data selectioncontains 979 430 BOSS galaxies from both the Northern and SouthernGalactic Caps over the redshift range z = 0.2-0.6. We extract thehigher-order part of the MFs, detecting the deviation from the purelyGaussian case with χ ^2 ̃ O(10^3) on 24 degrees of freedom across theentire data selection. We measure significant redshift evolution in thehigher-order functionals for the first time. We find 15-35{{ per cent}}growth, depending on functional and scale, between our redshift binscentred at z = 0.325 and z = 0.525. We show that the structure inhigher-order correlations grows faster than that in the two-pointcorrelations, especially on small scales where the excess approaches afactor of 2. We demonstrate how this trend is generalizable by findinggood agreement of the data with a hierarchical model in which the higherorders grow faster than the lower-order correlations. We find that thenon-Gaussianity of the underlying dark matter field grows even fasterthan the one of the galaxies. Our method can be adapted to study theredshift evolution of the three-point and higher functions individually.