Modelling the selection of galaxy groups with end-to-end simulations
Loading...
Access rights
openAccess
CC BY
CC BY
publishedVersion
URL
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Date
Department
Major/Subject
Mcode
Degree programme
Language
en
Pages
26
Series
Astronomy & Astrophysics, Volume 699, pp. 1-26
Abstract
Context. Feedback from supernovae and active galactic nuclei (AGN) shapes the galaxy formation and evolution, but its impact remains unclear. Galaxy groups offer a crucial probe to determine this impact because their gravitational binding energy is comparable to the energy that is available from their central AGN. The XMM-Newton Group AGN Project (X-GAP) is a sample of 49 groups that were selected in the X-ray (ROSAT) and optical (SDSS) bands and provides a benchmark for hydrodynamical simulations. Aims. For this comparison, it is essential to understand the selection effects. We model the selection function of X-GAP by forward-modelling the detection process in the X-ray and optical bands. Methods. Using the Uchuu N-body simulation, we built a dark matter halo light cone, predicted X-ray group properties with a neural network trained on hydrodynamical simulations, and assigned matching observed properties to the galaxies. We compared the selected sample to the parent population in the light cone. Results. Our method provided a sample that matched the observed distribution of the X-ray luminosity and velocity dispersion. A completeness of 50% was reached at a velocity dispersion of 450 km/s in the X-GAP redshift range. The selection is driven by X-ray flux, with a secondary dependence on the velocity dispersion and redshift. We estimated a purity level of 93% for the X-GAP parent sample. We calibrated the relation of the velocity dispersion to the halo mass. We found a normalisation and slope that agree with the literature and an intrinsic scatter of about 0.06 dex. The measured velocity dispersion is only accurate within 10% for rich systems with more than about 20 members, and the velocity dispersion for groups with fewer than 10 members is biased at more than 20%. Conclusions. The X-ray follow-up refines the optical selection and enhances the purity, but reduces completeness. In an SDSS-like setup, measurement errors for the velocity dispersion dominate the intrinsic scatter. Our selection model enables unbiased comparisons of thermodynamic properties and gas fractions between X-GAP groups and hydrodynamical simulations.Description
Publisher Copyright: © The Authors 2025.
Other note
Citation
Seppi, R, Eckert, D, Finoguenov, A, Shreeram, S, Tempel, E, Gozaliasl, G, Lorenz, M, Wilms, J, Mamon, G A, Gastaldello, F, Lovisari, L, O’Sullivan, E, Kolokythas, K, Bourne, M A, Sun, M & Pillepich, A 2025, 'Modelling the selection of galaxy groups with end-to-end simulations', Astronomy & Astrophysics, vol. 699, A206, pp. 1-26. https://doi.org/10.1051/0004-6361/202553977