Projects per year
Abstract
Galaxy clusters and groups are important cosmological probes and giant
cosmic laboratories for studying galaxy evolution. Much effort has been
devoted to understanding how and when baryonic matter cools at the
centre of potential wells. However, a clear picture of the efficiency
with which baryons are converted into stars is still missing. We present
the K-band luminosity–halo mass relation, LK,500−M500,WL,
for a subsample of 20 of the 100 brightest clusters in the XXL Survey
observed with WIRCam at the Canada-France-Hawaii Telescope (CFHT). For
the first time, we have measured this relation via weak-lensing analysis
down to M500,WL = 3.5 × 1013 M⊙. This allows us to investigate whether the slope of the LK−M relation is different for groups and clusters, as seen in other works. The clusters in our sample span a wide range in mass, M500,WL = 0.35−12.10 × 1014 M⊙, at 0 < z < 0.6. The K-band luminosity scales as log 10(LK,500/ 1012 L⊙) ∝ βlog 10(M500,WL/ 1014 M⊙) with β = 0.85+0.35-0.27 and an intrinsic scatter of σlnLK|M = 0.37+0.19-0.17.
Combining our sample with some clusters in the Local Cluster
Substructure Survey (LoCuSS) present in the literature, we obtain a
slope of 1.05+0.16-0.14 and an intrinsic scatter of 0.14+0.09-0.07. The flattening in the LK−M
seen in previous works is not seen here and might be a result of a bias
in the mass measurement due to assumptions on the dynamical state of
the systems. We also study the richness-mass relation and find that
group-sized halos have more galaxies per unit halo mass than massive
clusters. However, the brightest cluster galaxy (BCG) in low-mass
systems contributes a greater fraction to the total cluster light than
BCGs do in massive clusters; the luminosity gap between the two
brightest galaxies is more prominent for group-sized halos. This result
is a natural outcome of the hierarchical growth of structures, where
massive galaxies form and gain mass within low-mass groups and are
ultimately accreted into more massive clusters to become either part of
the BCG or one of the brighter galaxies.
Original language | English |
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Article number | A9 |
Number of pages | 10 |
Journal | Astronomy and Astrophysics |
Volume | 592 |
Early online date | 15 Jun 2016 |
DOIs | |
Publication status | Published - Aug 2016 |
Keywords
- galaxies: clusters: general
- galaxies: photometry
- gravitational lensing: weak
- galaxies: stellar content
- X-rays: galaxies: clusters
- galaxies: groups: general
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Dive into the research topics of 'The XXL Survey: X. K-band luminosity - weak-lensing mass relation for groups and clusters of galaxies'. Together they form a unique fingerprint.Projects
- 2 Finished
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Research in planetary formation, astrophysics, and cosmology at Bristol
Birkinshaw, M. (Principal Investigator)
1/04/15 → 31/03/18
Project: Research
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Research in planetary physics, astrophysics and cosmology at Bristol
Birkinshaw, M. (Principal Investigator)
1/04/12 → 1/04/15
Project: Research