Linking X-ray emission to galaxy populations in GAMA groups
Abstract
We study how the presence of a detectable hot intragroup medium affects galaxy colour and star-formation properties, and how these trends depend on dynamical stage within the group. We analysed galaxies in GAMA groups with and without X-ray detection (XG and NXG) at 0.1 <= z <= 0.2, using samples with similar halo-mass distributions, compared with a field control sample. Galaxies were classified as red, green, or blue by UV-optical colour, and group galaxies further classified into dynamical classes based on projected phase-space position and host halo mass. We examined galaxy populations as a function of orbital class, star-formation activity, nuclear activity, and cluster-centric distance. The galaxy population is systematically more evolved in XG than NXG, with lower blue and star-forming fractions and higher red and passive fractions. The green fraction is stable across environments and orbital classes, though high-mass recent arrivals show a mild excess of green systems while retaining relatively high star-forming and low passive fractions, suggesting an intermediate quenching stage. The active galactic nucleus fraction shows no environmental dependence, while the post-starburst fraction increases strongly in XG, reaching nearly 20 percent, consistent with enhanced rapid quenching. Galaxy properties show stronger radial segregation in XG than NXG, with colour fractions differing from field values even at R/R200 ~ 3, consistent with preprocessing. Despite similar halo-mass distributions, the systematic differences between XG and NXG show that halo mass alone does not determine galaxy properties. A detectable hot intragroup medium is associated with enhanced environmental processing, stronger quenching, and more frequent rapid transitions, highlighting the role of the intragroup medium's thermodynamical state, beyond halo mass, in shaping galaxy evolution at group scales.
Related
- Galaxy And Mass Assembly (GAMA): The Most Isolated GAMA Galaxies
- A Graph Attention Network Framework for Simultaneous Prediction of Galaxy and Dark Matter Halo Properties in GAMA DR4
- X-rays from Low-mass Active Galaxies in the Galaxy And Mass Assembly (GAMA) Survey
- Investigating radio source population and spatial characteristics of diffuse Galactic synchrotron emission in the GAMA-23 field with uGMRT Band-3
- The thermal emission for knot A of radio galaxy M87 by Chandra
BibTeX
@misc{levis2026linking,
title = {{Linking X-ray emission to galaxy populations in GAMA groups}},
author = {Selene Levis and Hernán Muriel and Valeria Coenda and Andrea Biviano and Héctor J. Martínez and Martín de los Rios},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.22427},
eprint = {2609.22427},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.22427},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Linking X-ray emission to galaxy populations in GAMA groups
AU - Selene Levis
AU - Hernán Muriel
AU - Valeria Coenda
AU - Andrea Biviano
AU - Héctor J. Martínez
AU - Martín de los Rios
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.22427
UR - https://arxiv.org/abs/2609.22427
AB - We study how the presence of a detectable hot intragroup medium affects galaxy colour and star-formation properties, and how these trends depend on dynamical stage within the group. We analysed galaxies in GAMA groups with and without X-ray detection (XG and NXG) at 0.1 <= z <= 0.2, using samples with similar halo-mass distributions, compared with a field control sample. Galaxies were classified as red, green, or blue by UV-optical colour, and group galaxies further classified into dynamical classes based on projected phase-space position and host halo mass. We examined galaxy populations as a function of orbital class, star-formation activity, nuclear activity, and cluster-centric distance. The galaxy population is systematically more evolved in XG than NXG, with lower blue and star-forming fractions and higher red and passive fractions. The green fraction is stable across environments and orbital classes, though high-mass recent arrivals show a mild excess of green systems while retaining relatively high star-forming and low passive fractions, suggesting an intermediate quenching stage. The active galactic nucleus fraction shows no environmental dependence, while the post-starburst fraction increases strongly in XG, reaching nearly 20 percent, consistent with enhanced rapid quenching. Galaxy properties show stronger radial segregation in XG than NXG, with colour fractions differing from field values even at R/R200 ~ 3, consistent with preprocessing. Despite similar halo-mass distributions, the systematic differences between XG and NXG show that halo mass alone does not determine galaxy properties. A detectable hot intragroup medium is associated with enhanced environmental processing, stronger quenching, and more frequent rapid transitions, highlighting the role of the intragroup medium's thermodynamical state, beyond halo mass, in shaping galaxy evolution at group scales.
ER -