Galaxy And Mass Assembly (GAMA): The absence of stellar mass segregation in galaxy groups and consistent predictions from GALFORM and EAGLE simulations

Abstract

We investigate the contentious issue of the presence, or lack thereof, of satellites mass segregation in galaxy groups using the Galaxy And Mass Assembly (GAMA) survey, the GALFORM semi-analytic and the EAGLE cosmological hydrodynamical simulation catalogues of galaxy groups. We select groups with halo mass $12⩽\log (M_{\text{halo}}/h^{-1}{M}_{\odot })<14.5$ and redshift $z⩽0.32$ and probe the radial distribution of stellar mass out to twice the group virial radius. All the samples are carefully constructed to be complete in stellar mass at each redshift range and efforts are made to regularise the analysis for all the data. Our study shows negligible mass segregation in galaxy group environments with absolute gradients of $\lesssim 0.08$ dex and also shows a lack of any redshift evolution. Moreover, we find that our results at least for the GAMA data are robust to different halo mass and group centre estimates. Furthermore, the EAGLE data allows us to probe much fainter luminosities ($r$-band magnitude of 22) as well as investigate the three-dimensional spatial distribution with intrinsic halo properties, beyond what the current observational data can offer. In both cases we find that the fainter EAGLE data show a very mild spatial mass segregation at $z⩽0.22$, which is again not apparent at higher redshift. Interestingly, our results are in contrast to some earlier findings using the Sloan Digital Sky Survey. We investigate the source of the disagreement and suggest that subtle differences between the group finding algorithms could be the root cause.

17 pages, 10 figures, Accepted for publication in MNRAS

References in corpus (13)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Galaxy Groups in the SDSS DR4: I. The Catalogue and Basic Properties
• The SAMI Galaxy Survey: instrument specification and target selection
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• The Unorthodox Orbits of Substructure Halos
• Dark matter halo properties of GAMA galaxy groups from 100 square degrees of KiDS weak lensing data
• The zCOSMOS 20k Group Catalog
• Galaxy and Mass Assembly (GAMA): The halo mass of galaxy groups from maximum-likelihood weak lensing
• The GEEC2 spectroscopic survey of Galaxy Groups at $0.8<z<1$
• Satellite Ecology: The Dearth of Environment Dependence
• Mass segregation trends in SDSS galaxy groups

Cited by in corpus (7)

• Galaxy And Mass Assembly (GAMA): Environmental Quenching of Centrals and Satellites in Groups
• Quenching low-mass satellite galaxies: evidence for a threshold ICM density
• Galaxy and Mass Assembly (GAMA): Formation and Growth of Elliptical Galaxies in the Group Environment
• YZiCS: On the Mass Segregation of Galaxies in Clusters
• Galaxy And Mass Assembly (GAMA): The group HI mass as a function of halo mass
• Galaxy and Mass Assembly (GAMA): the clustering of galaxy groups
• Exploring the effect of baryons on the radial distribution of satellite galaxies with GAMA and IllustrisTNG