Formation of Galaxy Clusters

By Andrey V. Kravtsov, Stefano Borgani. 2012

639 citations recorded by the source corpus.

Formation of galaxy clusters corresponds to the collapse of the largest gravitationally bound overdensities in the initial density field and is accompanied by the most energetic phenomena since the Big Bang and by the complex interplay between gravity-induced dynamics of collapse and baryonic processes associated with galaxy formation. Galaxy clusters are, thus, at the cross-roads of cosmology and astrophysics and are unique laboratories for testing models of gravitational structure formation, galaxy evolution, thermodynamics of the intergalactic medium, and plasma physics. At the same time, their large masses make them a useful probe of growth of structure over cosmological time, thus providing cosmological constraints that are complementary to other probes. In this review, we describe our current understanding of cluster formation: from the general picture of collapse from initial density fluctuations in an expanding Universe to detailed simulations of cluster formation including the effects of galaxy formation. We outline both the areas in which highly accurate predictions of theoretical models can be obtained and areas where predictions are uncertain due to uncertain physics of galaxy formation and feedback. The former includes the description of the structural properties of the dark matter halos hosting clusters, their mass function, and clustering properties. Their study provides a foundation for cosmological applications of clusters and for testing the fundamental assumptions of the standard model of structure formation. The latter includes the description of the total gas and stellar fractions and the thermodynamical and nonthermal processes in the intracluster plasma. Their study serves as a testing ground for galaxy formation models and plasma physics. In this context, we identify a suitable radial range where the observed thermal properties of the intracluster plasma exhibit the most regular behavior and, thus, can be used to define robust observational proxies for the total cluster mass. Finally, we discuss the formation of clusters in nonstandard cosmological models, such as non-Gaussian models for the initial density field and models with modified gravity, along with prospects for testing these alternative scenarios with large cluster surveys in the near future.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/0b537e7d26224b2501f0abb0316cb6d127e5b389

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Citations in the corpus

Cluster Cosmology Constraints from the 2500 deg2 SPT-SZ Survey: Inclusion of Weak Gravitational Lensing Data from Magellan and the Hubble Space Telescope (2018, background): “…to challenge the paradigms of a cosmological constant and of general relativity and, when analyzed jointly with measurements of primary anisotropies in the cosmic microwave background (CMB), to measure the sum of neutrino masses (for reviews, see, e.g., Allen et al. 2011; Kravtsov & Borgani 2012).”
Observational probes of cosmic acceleration (2012, background): “Other recent reviews in the field include Kravtsov and Borgani (2012), who review the physics of cluster formation with emphasis on the insights gained from hydrodynamic cosmological simulations, and Kneib and Natarajan (2011), who review strong and weak lensing by clusters.”
Planck intermediate results: V. Pressure profiles of galaxy clusters from the Sunyaev-Zeldovich effect (2012, positive): “The processes governing the thermodynamical state of the outer regions in clusters still need to be understood from the theoretical and observational points of view (see Kravtsov & Borgani 2012, for a review and references).”
Structure finding in cosmological simulations: the state of affairs (2013, background): “We just like to state that equation (2) may not be the appropriate choice in the end as it leads to spurious (and unphysical) evolution as, for instance, shown and discussed by Diemand et al. (2007), Diemer et al. (2012) and Kravtsov & Borgani (2012).”
An improved SPH scheme for cosmological simulations (2015, methodology): “For the definition of entropy, we use S = T/ne2/3, which is commonly used in X-ray studies of the ICM (e.g. Kravtsov & Borgani 2012).”
Raining on black holes and massive galaxies: the top-down multiphase condensation model (2016, background): “Such haloes emerge from the virialization shocks of cosmological structures (Kravtsov & Borgani 2012) and cool down via radiative emission (Section 2.4).”
GALAXY CLUSTERS DISCOVERED VIA THE SUNYAEV–ZEL'DOVICH EFFECT IN THE 2500-SQUARE-DEGREE SPT-SZ SURVEY (2014, background): “Clusters are also unique laboratories in which to characterize the interplay between gravitational and astrophysical processes (see Kravtsov & Borgani 2012 for a recent review).”
Theoretical Challenges in Galaxy Formation (2016, background): “This makes galaxies too massive with too high star formation rates in particular at the central regions (e.g. Kravtsov & Borgani 2012).”
The SPTpol Extended Cluster Survey (2019, methodology): “Clusters of galaxies, as tracers of the extreme peaks in the matter density field, are valuable tools for constraining cosmological and astrophysical models (see, e.g., Voit 2005; Allen et al. 2011; Kravtsov & Borgani 2012; Weinberg et al. 2013, and references therein).”
CLASH-VLT: The mass, velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 galaxy cluster MACS J1206.2-0847 (2013, background): “They are the most massive systems in dynamical equilibrium, and are thus extremely sensitive and effective cosmological probes, especially through the study of the clustermass function (e.g. Kravtsov & Borgani 2012, and references herein).”
First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies (2017, methodology): “…tidal disruption, interactions with the intra-cluster medium (ICM) itself, e.g., via ram-pressure stripping, and repeated high-speed galaxy encounters within the cluster grav- 1 Cluster Lensing and Supernova Survey with Hubble itational potential (see Kravtsov & Borgani 2012, for a review).”
The relation between velocity dispersion and mass in simulated clusters of galaxies: dependence on the tracer and the baryonic physics (2013, background): “When these are not available, it is still possible to infer cluster mass from other observed quantities, the socalled mass proxies, which are at the same time relatively easy to measure and characterised by tight scaling relations with cluster mass (e.g. Kravtsov & Borgani 2012).”
The realm of the galaxy protoclusters (2016, background): “…of this review The study of galaxy clusters goes back almost a century, and there exist many excellent reviews on galaxy clusters (e.g., Bahcall, 1977; Dressler, 1984; Norman, 2007; Allen et al., 2011; Rosati et al., 2002; Kravtsov & Borgani, 2012; Vikhlinin et al., 2014; Bykov et al., 2015).”
Diffuse Radio Emission from Galaxy Clusters (2019, methodology): “Galaxy clusters form by accretion from the WHIM and through a sequence of mergers of clusters and groups (e.g., Peebles & Yu 1970; Press & Schechter 1974; Voit 2005; Kravtsov & Borgani 2012).”
THE PSEUDO-EVOLUTION OF HALO MASS (2012, methodology): “The observable properties of clusters, such as X-ray temperature, entropy profile, the mass of the intracluster gas, or their evolution with redshift, are often described using a self-similar model (Kaiser 1986, see also Kravtsov & Borgani 2012for a review).”
JOINT ANALYSIS OF CLUSTER OBSERVATIONS. II. CHANDRA/XMM-NEWTON X-RAY AND WEAK LENSING SCALING RELATIONS FOR A SAMPLE OF 50 RICH CLUSTERS OF GALAXIES (2012, background): “The phenomenon of inherent correlation is discussed in greater detail by Kravtsov & Borgani (2012), and arises because the aperture used to measure the mass is highly correlated with the observable on the other axis (in this case, X-ray r500 and X-ray temperature are highly correlated).”
The halo mass function through the cosmic ages (2012, background): “…in statistical analyses of cluster surveys to constrain cosmological parameters (Smith & Marian 2011) as these large objects probe the high-mass end of the function (for a recent review paper on the formation of galaxy clusters, including the role of the mass function, see Kravtsov & Borgani 2012).”
Star formation sustained by gas accretion (2014, background): “…(Silich et al. 2010; Hopkins et al. 2013a; Trujillo-Gomez et al. 2013), secular evolution (Binney 2013; Kormendy 2013), dense cluster environments (Santini 2011; Kravtsov & Borgani 2012), and the growth of black holes (BH) through cosmic gas accretion (Husemann et al. 2011; Chen et al. 2013).”