The hierarchical growth of bright central galaxies and intracluster light as traced by the magnitude gap

ABSTRACT Using a sample of 2800 galaxy clusters identified in the Dark Energy Survey across the redshift range $0.20 \lt z \lt 0.60$, we characterize the hierarchical assembly of bright central galaxies (BCGs) and the surrounding intracluster light (ICL). To quantify hierarchical formation we use the stellar mass–halo mass (SMHM) relation, comparing the halo mass, estimated via the mass–richness relation, to the stellar mass within the BCG + ICL system. Moreover, we incorporate the magnitude gap (M14), the difference in brightness between the BCG (measured within 30 kpc) and fourth brightest cluster member galaxy within 0.5 $R_{200,c}$, as a third parameter in this linear relation. The inclusion of M14, which traces BCG hierarchical growth, increases the slope and decreases the intrinsic scatter, highlighting that it is a latent variable within the BCG + ICL SMHM relation. Moreover, the correlation with M14 decreases at large radii. However, the stellar light within the BCG + ICL transition region (30 –80 kpc) most strongly correlates with halo mass and has a statistically significant correlation with M14. Since the transition region and M14 are independent measurements, the transition region may grow due to the BCG’s hierarchical formation. Additionally, as M14 and ICL result from hierarchical growth, we use a stacked sample and find that clusters with large M14 values are characterized by larger ICL and BCG + ICL fractions, which illustrates that the merger processes that build the BCG stellar mass also grow the ICL. Furthermore, this may suggest that M14 combined with the ICL fraction can identify dynamically relaxed clusters.

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Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-02-13
DOI
https://doi.org/10.1093/mnras/staf277
Citations
14
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
16.17

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article

The hierarchical growth of bright central galaxies and intracluster light as traced by the magnitude gap

A. Pieres, Ting-Yun Cheng, S. Everett, I. Ferrero et al.
14 citations
Monthly Notices of the Royal Astronomical Society
Galaxies: Formation, Evolution, Phenomena
16.17
article

The hierarchical growth of bright central galaxies and intracluster light as traced by the magnitude gap

A. Pieres, Ting-Yun Cheng, S. Everett, I. Ferrero, S. R. Hinton, M. Gatti, J. Carretero, J. García-Bellido, L. N. da Costa, G. Giannini, Michael S. Schubnell, D. Gruen, A. A. Plazas, Gregory Tarlé, E. Suchyta, P. Wiseman, A. R. Walker, Matt Hilton, D. J. James, A. Palmese, Eusebio Sanchez, J. Mena-Fernández, A. Carnero Rosell, J. De Vicente, F. Menanteau, J. J. Mohr, N Weaverdyck, Jesse B. Golden-Marx, S. Lee, R. L. C. Ogando, M. E. S. Pereira, David H. Brooks, F. Andrade-Oliveira, M. Aguena, I. Sevilla-Noarbe, Y Zhang, D L Hollowood, G Gutierrez, R Miquel, P. Doel, S Samuroff, B Yanny, Klaus Honscheid, M. Smith, D. Bacon, S Desai, V. Vikram, K. Kuehn, S. Allam, R. A. Gruendl
article en
14 citations

Abstract

ABSTRACT Using a sample of 2800 galaxy clusters identified in the Dark Energy Survey across the redshift range $0.20 \lt z \lt 0.60$, we characterize the hierarchical assembly of bright central galaxies (BCGs) and the surrounding intracluster light (ICL). To quantify hierarchical formation we use the stellar mass–halo mass (SMHM) relation, comparing the halo mass, estimated via the mass–richness relation, to the stellar mass within the BCG + ICL system. Moreover, we incorporate the magnitude gap (M14), the difference in brightness between the BCG (measured within 30 kpc) and fourth brightest cluster member galaxy within 0.5 $R_{200,c}$, as a third parameter in this linear relation. The inclusion of M14, which traces BCG hierarchical growth, increases the slope and decreases the intrinsic scatter, highlighting that it is a latent variable within the BCG + ICL SMHM relation. Moreover, the correlation with M14 decreases at large radii. However, the stellar light within the BCG + ICL transition region (30 –80 kpc) most strongly correlates with halo mass and has a statistically significant correlation with M14. Since the transition region and M14 are independent measurements, the transition region may grow due to the BCG’s hierarchical formation. Additionally, as M14 and ICL result from hierarchical growth, we use a stacked sample and find that clusters with large M14 values are characterized by larger ICL and BCG + ICL fractions, which illustrates that the merger processes that build the BCG stellar mass also grow the ICL. Furthermore, this may suggest that M14 combined with the ICL fraction can identify dynamically relaxed clusters.

Monthly Notices of the Royal Astronomical SocietyVol. 538(2)
Institució Catalana de Recerca i Estudis Avançats (ES), California Institute of Technology (US), Argonne National Laboratory (US), Oak Ridge National Laboratory (US), Northeastern University (US), Fermi National Accelerator Laboratory (US), Jet Propulsion Laboratory (US), University of Nottingham (GB), Lawrence Berkeley National Laboratory (US), University of Illinois Urbana-Champaign (US), Universität Hamburg (DE), The University of Queensland (AU), University of Oslo (NO), Institute for High Energy Physics (ES), Durham University (GB), University of the Witwatersrand (ZA), University of Michigan (US), Lowell Observatory (US), SLAC National Accelerator Laboratory (US), Australian Astronomical Observatory (AU), University of Chicago (US), Valongo Observatory (BR), Kavli Institute for Particle Astrophysics and Cosmology (US), Center for Astrophysics Harvard & Smithsonian (US), Instituto de Astrofísica de Canarias (ES), National Center for Supercomputing Applications (US), Cerro Tololo Inter-American Observatory (CL), Laboratoire de Physique Subatomique et de Cosmologie (FR), NSF NOIRLab (US), Laboratório Interinstitucional de e-Astronomia (BR), Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES), University of Southampton (GB), Institute of Science and Technology, University College London (GB), The Ohio State University (US), University of Portsmouth (GB), Universidad Autónoma de Madrid (ES), Indian Institute of Technology Hyderabad (IN), Lancaster University (GB), Carnegie Mellon University (US), University of Pennsylvania (US), Ludwig-Maximilians-Universität München (DE), University of KwaZulu-Natal (ZA), University of California, Berkeley (US), Macquarie University (AU)
National Science Foundation, U.S. Department of Energy, Ohio State University, University of Portsmouth, Centres de Recerca de Catalunya, European Commission, University of Sussex, Generalitat de Catalunya, Conselho Nacional de Desenvolvimento Científico e Tecnológico, China Scholarship Council, Ministerio de Ciencia e Innovación, Institut de Física d'Altes Energies, University of Illinois at Urbana-Champaign, Office of Science, Science and Technology Facilities Council, European Regional Development Fund, High Energy Physics, Integrated Electronics Engineering Center, Binghamton University, Fermilab, Lawrence Berkeley National Laboratory, SLAC National Accelerator Laboratory
Openalex Percentile: Top 1%
Galaxies: Formation, Evolution, Phenomena
16.17
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