Filament profiles from WISExSCOS galaxies as probes of the impact of environmental effects

¹ Institut d’Astrophysique Spatiale, CNRS, Université Paris-Sud, Bâtiment 121, Orsay, France
e-mail: victor.bonjean@ias.u-psud.fr
² LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, 75014 Paris, France

Received: 13 December 2019
Accepted: 19 March 2020

Abstract

The role played by large-scale structures in galaxy evolution is not very well understood yet. In this study, we investigated properties of galaxies in the range 0.1 <  z <  0.3 from a value-added version of the WISExSCOS catalogue around cosmic filaments detected with DisPerSE. We fitted a profile of galaxy over-density around cosmic filaments and found a typical radius of r_m = 7.5 ± 0.2 Mpc. We measured an excess of passive galaxies near to the spine of the filament that was higher than the excess of transitioning and active galaxies. We also detected star formation rates (SFR) and stellar mass (M_⋆) gradients pointing towards the spine of the filament. We investigated this result and found an M_⋆ gradient for each type of galaxy, that is active, transitioning, and passive; we found a positive SFR gradient for passive galaxies. We also linked the galaxy properties and gas content in the cosmic web. To do so, we investigated the quiescent fraction f_Q profile of galaxies around the cosmic filaments. Based on recent studies about the effect of the gas and the cosmic web on galaxy properties, we modelled f_Q with a β model of gas pressure. The slope obtained in this work, β = 0.54 ± 0.18, is compatible with the scenario of projected isothermal gas in hydrostatic equilibrium (β = 2/3) and with the profiles of gas fitted in Sunyaev-Zel’dovich data from the Planck satellite.