Galaxies infalling into groups: filaments versus isotropic infall

Abstract

We perform a comparative analysis of the properties of galaxies infalling into groups classifying them accordingly to whether they are: falling along filamentary structures; or they are falling isotropically. For this purpose, we identify filamentary structures connecting massive groups of galaxies in the SDSS. We perform a comparative analysis of some properties of galaxies in filaments, in the isotropic infall region, in the field, and in groups. We study the luminosity functions (LF) and the dependence of the specific star formation rate (SSFR) on stellar mass, galaxy type, and projected distance to the groups that define the filaments. We find that the LF of galaxies in filaments and in the isotropic infalling region are basically indistinguishable between them, with the possible exception of late-type galaxies. On the other hard, regardless of galaxy type, their LFs are clearly different from that of field or group galaxies. Both of them have characteristic absolute magnitudes and faint end slopes in between the field and group values. More significant differences between galaxies in filaments and in the isotropic infall region are observed when we analyse the SSFR. We find that galaxies in filaments have a systematically higher fraction of galaxies with low SSFR as a function of both, stellar mass and distance to the groups, indicating a stronger quenching of the star formation in the filaments compared to both, the isotropic infalling region, and the field. Our results suggest that some physical mechanisms that determine the differences observed between field galaxies and galaxies in systems, affect galaxies even when they are not yet within the systems.

Large-Scale Filamentary Structures Around the Virgo Cluster Revisited

“…Balogh et al 2004;Ebeling et al 2004;Porter et al 2008;Yoon et al 2012;Guo et al 2015;Martínez et al 2016). Indeed, as the majority of filament galaxies are faint dwarf galaxies, with low binding energies, they are easily affected by even weak perturbations.…”

A comparison of cosmological filaments catalogues

“…2.3 Filaments linking groups of galaxies (M16) Martínez et al (2016) build a sample of filaments using a galaxy group catalogue from Zandivarez & Martínez (2011) as nodes. Filaments consist of pairs of close galaxy groups that are linked by an overdensity of galaxies (see their Fig.…”

“…All the characteristics shown in this section suggest that properties of each catalogue strongly depend in the way they were build. Tempel et al (2014b) algorithm is based on geometrical and stochastic assumptions of the distribution of galaxies, whereas Martínez et al (2016) algorithm detects overdensities between galaxy groups and Pereyra et al (2019) method finds filaments as paths of luminous galaxies.…”

“…If this were the case, galaxies near the nodes should have been flowing through the filament for longer time than galaxies in the centre or saddle point. This would cause that the closer a galaxy is to the nodes (as shown by Martínez et al 2016, andSalerno et al 2019), the redder it is. We show in Fig.…”

Gas and galaxies in filaments between clusters of galaxies

“…The photometric properties of the galaxies in the inter-cluster filament, their star-formation evolution, their weak lensing properties, etc. were performed in many selected cluster (or group) pairs (e.g., Fadda et al 2008;Gallazzi et al 2009;Edwards et al 2010;Zhang et al 2013;Martínez et al 2016;Epps & Hudson 2017 A&A proofs: manuscript no. aa_new may show substructures or evidence of dynamical effect: they merge, interact, and accrete smaller groups.…”