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We present scaling relations between the integrated Sunyaev–Zel’dovich effect (SZE) signal, Y_(SZ), its X-ray
analogue, Y_X ≡ M_(gas)T_X, and total mass, M_(tot), for the 45 galaxy clusters in the Bolocam X-ray SZ (BOXSZ) sample.
All parameters are integrated within r_(2500). Y_(2500) values are measured using SZE data collected with Bolocam,
opera...
Contexts in source publication
Context 1
... to the weak covariance of L x with T X and Y SZ , the BOXSZ selection has very little impact on the θ t|m and θ y|m relations, although our underlying fitting procedure does produce small biases in those two relations which we correct for. The selection bias cor- rected scaling relations are presented in Table 4, and the correction factors are given in Table 6 of Appendix C. The recovered θ t|m and θ l|m relations are consistent with those presented using a full Bayesian analysis of a sample of 94 clusters in M10. The scaling relation results will be discussed in detail in Section 6. ...
Context 2
... of the measured BOXSZ scaling relations are given in Table 4, and Y 2500 -Y X and Y 2500 -M 2500 relations are plotted in Figure 7. Starting with the Y 2500 -Y X relation, we measure the slope, β y|yx 1 = 0.84 ± 0.07, to be ap- proximately 2σ from unity. For the Y 2500 -M 2500 relation, plotted in the right-hand panel of Figure 7, we measure a best-fit slope β y|m 1 = 1.06 ± 0.12, which is approxi- mately 5σ away from the self-similar slope of 5/3. ...
Context 3
... consistency, we check to see whether our X-ray data also exhibit deviations from self-similarity, and we include the best-fit T X -M 2500 and Y X -M 2500 scaling rela- tions to the BOXSZ sample in Table 4 as well. The best- fit slope to the T X -M 2500 relation, β t|m 1 =0.35 ± 0.05, is also inconsistent with a self-similar slope of 2/3. ...
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Citations
... which is sensitive to a wide range of redshifts, we can detect massive clusters at various epochs (e.g., Reichardt et al. 2013). The integrated tSZ signal of individual clusters, known as the Compton-y parameter, can serve as a mass proxy via the use of scaling relations (Czakon et al. 2015;Salvati et al. 2019), and redshift-calibrated cluster counts can constrain the shape of the halo mass function on the high-mass end, which is highly sensitive to the amplitude of density fluctuations, the sum of the neutrino masses, and the amount of dark energy (Hurier & Lacasa 2017;Madhavacheril et al. 2017;Horowitz & Seljak 2017;Salvati et al. 2018;Makiya et al. 2020). Additionally, one can study the spatial distribution of the tSZ signal through two-point and higherorder correlation functions, as performed by the Planck, the Atacama Cosmology Telescope (ACT), and the South Pole Telescope (SPT) collaborations (Planck Collaboration et al. 2016;Choi et al. 2020;Bleem et al. 2015). ...
In the coming years, Sunyaev-Zel'dovich (SZ) measurements can dramatically improve our understanding of the Intergalactic Medium (IGM) and the role of feedback processes on galaxy formation, allowing us to calibrate important astrophysical systematics in cosmological constraints from weak lensing galaxy clustering surveys. However, the signal is only measured in a two-dimensional projection, and its correct interpretation relies on understanding the connection between observable quantities and the underlying intrinsic properties of the gas, in addition to the relation between the gas and the underlying matter distribution. One way to address these challenges is through the use of hydrodynamical simulations such as the high-resolution, large-volume MillenniumTNG suite. We find that measurements of the optical depth, $\tau$, and the Compton-y parameter, $Y$, receive large line-of-sight contributions which can be removed effectively by applying a Compensated Aperture Photometry (CAP) filter. In contrast with other $\tau$ probes (e.g., X-rays and Fast Radio Bursts), the kSZ-inferred $\tau$ receives most of its signal from a confined cylindrical region around the halo due to the velocity decorrelation along the line-of-sight. Additionally, we perform fits to the $Y-M$ and $\tau-M$ scaling relations and report best-fit parameters adopting the smoothly broken power law (SBPL) formalism. We note that subgrid physics modeling can broaden the error bar on these by 30\% for intermediate-mass halos ($\sim$$10^{13} \, {\rm M}_{\odot}$). The scatter of the scaling relations can be captured by an intrinsic dependence on concentration, and an extrinsic dependence on tidal shear. Finally, we comment on the effect of using galaxies rather than halos in real observations, which can bias the inferred SZ profiles by $\sim$20\% for $L_\ast$-galaxies.
... The work in Sayers et al. (2016) considered a set of 47 clusters with M 500 ä [3, 25] × 10 14 M e at z < 0.9, chosen from observations with Chandra and Bolocam (Sayers et al. 2011), on the basis of their redshifts and high X-ray temperatures; this sample slightly extended the one that had already been studied in Czakon et al. (2015), by including two additional clusters. This work focused on the reconstruction of the pressure profile for the cluster outskirts, based on measurements of the integrated y-profile from Bolocam and Planck data. ...
We provide novel constraints on the parameters defining the universal pressure profile (UPP) within clusters of galaxies, and explore their dependencies on cluster mass and redshift, from measurements of Sunyaev–Zel’dovich (SZ) Compton y- profiles. We employ both Planck 2015 MILCA and Atacama Cosmology Telescope (ACT) Data Release 4 y -maps over a common ∼2100 deg ² footprint. We combine existing cluster catalogs, based on Kilo Degree Survey, Sloan Digital Sky Survey, and Dark Energy Spectroscopic Instrument Legacy Imaging Surveys observations, for a total of 23,820 clusters, spanning the mass range 10 14.0 M ⊙ < M 500 < 10 15.1 M ⊙ and the redshift range 0.02 < z < 0.98. We split the clusters into three independent bins in mass and redshift; for each combination, we detect the stacked SZ cluster signal and extract the mean y angular profile. The latter is predicted theoretically by adopting a halo model framework, and a Markov Chain Monte Carlo approach is employed to estimate the UPP parameters, the hydrostatic mass bias b h , and possible cluster miscentering effects. We constrain [ P 0 , c 500 , α , β ] to [5.9, 2.0, 1.8, 4.9] with Planck and to [3.8, 1.3, 1.0, 4.4] with ACT, using the full cluster sample, in agreement with previous findings. We do not find any compelling evidence for residual mass or redshift dependencies, thus expanding the validity of the cluster pressure profile over much larger M 500 and z ranges; this is the first time that the model has been tested on such a large (complete and representative) cluster sample. Finally, we obtain loose constraints on the hydrostatic mass bias in the range 0.2–0.3, again in broad agreement with previous works.
... The work in Sayers et al. (2016) considered a set of 47 clusters with M 500 ∈ [3, 25]×10 14 M at z < 0.9, chosen from observations with Chandra and Bolocam (Sayers et al. 2011) on the basis of their redshift and high Xray temperature; this sample slightly extended the one already studied in Czakon et al. (2015) with the inclusion of two additional clusters. This work focused on the reconstruction of the pressure profile in the cluster outskirts, based on measurements of the integrated y profile from Bolocam and Planck data. ...
We provide novel constraints on the parameters defining the universal pressure profile (UPP) within clusters of galaxies, and explore their dependence on the cluster mass and redshift, from measurements of Sunyaev-Zel'dovich Compton-$y$ profiles. We employ both the $\textit{Planck}$ 2015 MILCA and the ACT-DR4 $y$ maps over the common $\sim 2,100\,\text{deg}^2$ footprint. We combine existing cluster catalogs based on KiDS, SDSS and DESI observations, for a total of 23,820 clusters spanning the mass range $10^{14.0}\,\text{M}_{\odot}<M_{500}<10^{15.1}\,\text{M}_{\odot}$ and the redshift range $0.02<z<0.98$. We split the clusters into three independent bins in mass and redshift; for each combination we detect the stacked SZ cluster signal and extract the mean $y$ angular profile. The latter is predicted theoretically adopting a halo model framework, and MCMCs are employed to estimate the UPP parameters, the hydrostatic mass bias $b_{\rm h}$ and possible cluster miscentering effects. We constrain $[P_0,c_{500},\alpha,\beta]$ to $[5.9,2.0,1.8,4.9]$ with $\textit{Planck}$ and to $[3.8,1.3,1.0,4.4]$ with ACT using the full cluster sample, in agreement with previous findings. We do not find any compelling evidence for a residual mass or redshift dependence, thus expanding the validity of the cluster pressure profile over much larger $M_{500}$ and $z$ ranges; this is the first time the model has been tested on such a large (complete and representative) cluster sample. Finally, we obtain loose constraints on the hydrostatic mass bias in the range 0.2-0.3, again in broad agreement with previous works.
... In contrast to its extreme mass and exceptional lensing properties, A370 is intriguingly faint in both X-ray and Sunyaev-Zel'dovich effect (SZE) signals and does not follow the X-ray/SZE observable-mass scaling relations (see Czakon et al. 2015). The X-ray brightness distribution revealed from Chandra observations is highly elongated in the north-south direction, showing a disturbed morphology with the brightest X-ray peak located about halfway between the two BCGs (Molnar et al. 2020). ...
... In their simulations, the initial virial masses of two progenitors were fixed to 1. for A370 assuming a generalized form of the NFW profile. Molnar et al. (2020) found that initial conditions of the two progenitors with an infall velocity of 3500 km s −1 and an impact parameter of 70 h −1 kpc can reproduce the positions and the offsets between the peaks of the X-ray emission and the total mass surface density, the amplitude of the integrated SZE signal (Czakon et al. 2015), and the relative LOS velocity between the two BCGs (V ≈ 1024 km s −1 ). Moreover, the bestmatching simulation reproduces well the velocity dispersion and the LOS velocity distribution of cluster member galaxies (Lagattuta et al. 2019;Molnar et al. 2020). ...
We present a detailed weak-lensing and X-ray study of the Frontier Fields galaxy cluster Abell 370, one of the most massive known lenses on the sky, using wide-field BR C z ′ Subaru/Suprime-Cam and Chandra X-ray observations. By combining two-dimensional (2D) shear and azimuthally averaged magnification constraints derived from Subaru data, we perform a lensing mass reconstruction in a free-form manner, which allows us to determine both the radial structure and 2D morphology of the cluster mass distribution. In a triaxial framework assuming a Navarro–Frenk–White density profile, we constrain the intrinsic structure and geometry of the cluster halo by forward modeling the reconstructed mass map. We obtain a halo mass M 200 = (1.54 ± 0.29) ×10 ¹⁵ h ⁻¹ M ⊙ , a halo concentration c 200 = 5.27 ± 1.28, and a minor–major axis ratio q a = 0.62 ± 0.23 with uninformative priors. Using a prior on the line-of-sight alignment of the halo major axis derived from binary merger simulations constrained by multi-probe observations, we find that the data favor a more prolate geometry with lower mass and lower concentration. From triaxial lens modeling with the line-of-sight prior, we find a spherically enclosed gas mass fraction of f gas = (8.4 ± 1.0)% at 0.7 h ⁻¹ Mpc ∼ 0.7 r 500 . When compared to the hydrostatic mass estimate ( M HE ) from Chandra observations, our triaxial weak-lensing analysis yields spherically enclosed mass ratios of 1 − b ≡ M HE / M WL = 0.56 ± 0.09 and 0.51 ± 0.09 at 0.7 h ⁻¹ Mpc with and without using the line-of-sight prior, respectively. Since the cluster is in a highly disturbed dynamical state, this represents the likely maximum level of hydrostatic bias in galaxy clusters.
... This template is then fit to the Bolocam data, with its normalization as the only free parameter, to obtain the average surface brightness of the SZ effect signal within R 2500 at a frequency of 139 GHz. R 2500 corresponds to the spherical radius enclosing an average density 2500 times the critical density of the universe, and in RX J1347.5-1145 is measured to be 0.71∼Mpc based on the analysis of Czakon et al. (2015). We note that the technique used to obtain R 2500 in Czakon et al. (2015) was based on a generalized scaling relation intended to be applicable to large, heterogeneous galaxy cluster samples. ...
... R 2500 corresponds to the spherical radius enclosing an average density 2500 times the critical density of the universe, and in RX J1347.5-1145 is measured to be 0.71∼Mpc based on the analysis of Czakon et al. (2015). We note that the technique used to obtain R 2500 in Czakon et al. (2015) was based on a generalized scaling relation intended to be applicable to large, heterogeneous galaxy cluster samples. For highly relaxed objects, like RX J1347.5-1145, ...
... more accurate methods are available (see, e.g., Mantz et al. 2014, who find a value of 0.80 Mpc). However, given that R 2500 is employed in this work solely as a convenient aperture size that is well matched to the observational data, and that Czakon et al. (2015) had previously computed the aperture photometry values from Bolocam data within R 2500 ∼ =0.71 Mpc, we retain that value for this analysis. ...
We present a measurement of the relativistic corrections to the thermal Sunyaev–Zel’dovich (SZ) effect spectrum, the rSZ effect, toward the massive galaxy cluster RX J1347.5-1145 by combining submillimeter images from Herschel-SPIRE with millimeter wavelength Bolocam maps. Our analysis simultaneously models the SZ effect signal, the population of cosmic infrared background galaxies, and the galactic cirrus dust emission in a manner that fully accounts for their spatial and frequency-dependent correlations. Gravitational lensing of background galaxies by RX J1347.5-1145 is included in our methodology based on a mass model derived from the Hubble Space Telescope observations. Utilizing a set of realistic mock observations, we employ a forward modeling approach that accounts for the non-Gaussian covariances between the observed astrophysical components to determine the posterior distribution of SZ effect brightness values consistent with the observed data. We determine a maximum a posteriori (MAP) value of the average Comptonization parameter of the intracluster medium (ICM) within R 2500 to be 〈 y 〉 2500 = 1.56 × 10 ⁻⁴ , with corresponding 68% credible interval [1.42, 1.63] × 10 ⁻⁴ , and a MAP ICM electron temperature of 〈 T sz 〉 2500 = 22.4 keV with 68% credible interval spanning [10.4, 33.0] keV. This is in good agreement with the pressure-weighted temperature obtained from Chandra X-ray observations, 〈 T x,pw 〉 2500 = 17.4 ± 2.3 keV. We aim to apply this methodology to comparable existing data for a sample of 39 galaxy clusters, with an estimated uncertainty on the ensemble mean 〈 T sz 〉 2500 at the ≃ 1 keV level, sufficiently precise to probe ICM physics and to inform X-ray temperature calibration.
... First, the tSZ effect is a powerful method to detect massive clusters, especially as the ability to detect clusters of a given mass is largely independent of redshift Hasselfield et al. 2013;Reichardt et al. 2013). The integrated tSZ signal, known as the integrated Compton-y parameter, for individual clusters can be used as a mass proxy through the use of scaling relations (Salvati et al. 2019;Czakon et al. 2015) and the resulting calibrated tSZ cluster counts, particularly when combined with measurements of their redshifts, are a very powerful probe of cosmology. For example, the counts are highly sensitive to the sum of the neutrino masses and the dark energy equation of state (Makiya et al. 2020;Horowitz & Seljak 2017;Aghanim et al. 2016;Hurier & Lacasa 2017;Salvati et al. 2018;Madhavacheril et al. 2017). ...
With the advent of high-resolution, low-noise CMB measurements, the ability to extract cosmological information from thermal Sunyaev-Zel'dovich effect and kinetic Sunyaev-Zel'dovich effect will be limited not by statistical uncertainties but rather by systematic and theoretical uncertainties. The theoretical uncertainty is driven by the lack of knowledge about the electron pressure and density. Thus we explore the electron pressure and density distributions in the IllustrisTNG hydrodynamical simulations, and we demonstrate that the cluster properties exhibit a strong dependence on the halo concentration -- providing some of the first evidence of cluster assembly bias in the electron pressure and density. Further, our work shows evidence for a broken power-law mass dependence, with lower pressure in lower mass halos than previous work and a strong evolution with mass of the radial correlations in the electron density and pressure. Both of these effects highlight the differing impact of active galactic nuclei and supernova feedback on the gas in galaxy groups compared to massive clusters. We verified that we see qualitatively similar features in the SIMBA hydro-dynamical simulations, suggesting these effects could be generic features. Finally, we provide a parametric formula for the electron pressure and density profile as a function of dark matter halo mass, halo concentration, and redshift. These fitting formulae can reproduce the distribution of density and pressure of clusters and will be useful in extracting cosmological information from upcoming CMB surveys.
... In contrast to its extreme mass and exceptional lensing properties, A370 is intriguingly faint in both X-ray and Sunyaev-Zel'dovich effect (SZE) signals and does not follow the X-ray/SZE observable-mass scaling relations (see Czakon et al. 2015). The X-ray brightness distribution revealed from Chandra observations is highly elongated in the north-south direction, showing a disturbed morphology with the brightest X-ray peak located about halfway between the two BCGs (Molnar et al. 2020). ...
... We forward model projected cluster lensing observations by projecting a triaxial or spherical NFW halo model along the line of sight (e.g., Corless et al. 2009;Sereno & Umetsu 2011;Umetsu et al. 2015;Chiu et al. 2018b). Molnar et al. (2020) found that initial conditions of the two progenitors with an infall velocity of 3500 km s −1 and an impact parameter of 70 h −1 kpc can reproduce the positions and the offsets between the peaks of the X-ray emission and the total mass surface density, the amplitude of the integrated SZE signal (Czakon et al. 2015), and the relative line-of-sight velocity between the two BCGs (V ≈ 1024 km s −1 ). Moreover, the best-matching simulation reproduces well the velocity dispersion and the line-of-sight velocity distribution of cluster member galaxies (Lagattuta et al. 2019;Molnar et al. 2020). ...
We present a detailed weak-lensing and X-ray study of the Frontier Fields galaxy cluster Abell 370, one of the most massive known lenses on the sky, using wide-field BRz Subaru/Sprime-Cam and Chandra X-ray observations. By combining 2D shear and azimuthally averaged magnification constraints derived from Subaru data, we perform a lensing mass reconstruction in a free-form manner, which allows us to determine both radial structure and 2D morphology of the cluster mass distribution. In a triaxial framework assuming an NFW density profile, we constrain the intrinsic structure and geometry of the cluster halo by forward modeling the reconstructed mass map. We obtain a halo mass $M_{200}=(1.54 \pm 0.29)\times 10^{15}h^{-1}M_\odot$, a halo concentration $c_{200}=5.27 \pm 1.28$, and a minor-major axis ratio $q_a=0.62 \pm 0.23$ with uninformative priors. Using a prior on the line-of-sight alignment of the halo major axis derived from binary merger simulations constrained by multi-probe observations, we find that the data favor a more prolate geometry with lower mass and lower concentration. From triaxial lens modeling with the line-of-sight prior, we find a spherically enclosed gas mass fraction of $f_\mathrm{gas}=(8.4 \pm 1.0)\%$ at $0.7h^{-1}$ Mpc. When compared to the hydrostatic mass estimate from Chandra observations, our triaxial weak-lensing analysis yields spherically enclosed mass ratios of $1-b=0.56 \pm 0.09$ and $0.51 \pm 0.09$ at $0.7h^{-1}$ Mpc with and without using the line-of-sight prior, respectively. Since the cluster is in a highly disturbed dynamical state, this represents the likely maximum level of hydrostatic bias in galaxy clusters. We also obtain a model-independent constraint of $M_\mathrm{2D}(<2.3h^{-1}\mathrm{Mpc})=(3.11 \pm 0.47)\times 10^{15}h^{-1}M_\odot$ for the projected mass of the whole system, including any currently unbound material around the cluster.
... This template is then fit to the Bolocam data, with its normalization as the only free parameter, to obtain the average surface brightness of the SZ effect signal within R 2500 at a frequency of 139 GHz. R 2500 corresponds to the spherical radius enclosing an average density 2500 times the critical density of the universe, and in RX J1347.5-1145 is measured to be 0.71 ∼ Mpc based on the analysis of Czakon et al. (2015). We note that the technique used to obtain R 2500 in Czakon et al. (2015) was based on a generalized scaling relation intended to be applicable to large, heterogeneous galaxy cluster samples. ...
... R 2500 corresponds to the spherical radius enclosing an average density 2500 times the critical density of the universe, and in RX J1347.5-1145 is measured to be 0.71 ∼ Mpc based on the analysis of Czakon et al. (2015). We note that the technique used to obtain R 2500 in Czakon et al. (2015) was based on a generalized scaling relation intended to be applicable to large, heterogeneous galaxy cluster samples. For highly relaxed objects, like RX J1347.5-1145, ...
... more accurate methods are available (see, e.g., Mantz et al. 2014, who find a value of 0.80 Mpc). However, given that R 2500 is employed in this work solely as a convenient aperture size that is well-matched to the observational data, and that Czakon et al. (2015) had previously computed aperture photometry values from Bolocam data within R 2500 ∼= 0.71 Mpc, we retain that value for this analysis. ...
We present a measurement of the relativistic corrections to the thermal Sunyaev-Zel'dovich (SZ) effect spectrum, the rSZ effect, toward the massive galaxy cluster RX J1347.5-1145 by combining sub-mm images from Herschel-SPIRE with mm-wave Bolocam maps. Our analysis simultaneously models the SZ effect signal, the population of cosmic infrared background (CIB) galaxies, and galactic cirrus dust emission in a manner that fully accounts for their spatial and frequency-dependent correlations. Gravitational lensing of background galaxies by RX J1347.5-1145 is included in our methodology based on a mass model derived from HST observations. Utilizing a set of realistic mock observations, we employ a forward modelling approach that accounts for the non-Gaussian covariances between observed astrophysical components to determine the posterior distribution of SZ effect brightness values consistent with the observed data. We determine a maximum a posteriori (MAP) value of the average Comptonization parameter of the intra-cluster medium (ICM) within R$_{2500}$ to be $\langle y \rangle_{2500} = 1.56 \times 10^{-4}$, with corresponding 68~per cent credible interval $[1.42,1.63] \times 10^{-4}$, and a MAP ICM electron temperature of $\langle \textrm{T}_{\textrm{sz}} \rangle_{2500} = 22.4$~keV with 68~per cent credible interval spanning $[10.4,33.0]$~keV. This is in good agreement with the pressure-weighted temperature obtained from {\it Chandra} X-ray observations, $\langle \textrm{T}_{\textrm{x,pw}}\rangle_{2500} = 17.4 \pm 2.3$~keV. We aim to apply this methodology to comparable existing data for a sample of 39 galaxy clusters, with an estimated uncertainty on the ensemble mean $\langle \textrm{T}_{\textrm{sz}} \rangle_{2500}$ at the $\simeq 1$~keV level, sufficiently precise to probe ICM physics and to inform X-ray temperature calibration.
... Motivated by this, Ueda et al. (2020) conducted a systematic study of ICM perturbations in the cool cores for a subsample of 12 cool-core clusters selected from the CLASH (Postman et al. 2012) sample of 25 massive clusters, for which deep multiwavelength observations are available (see, e.g., Biviano et al. 2013;Donahue et al. 2014Donahue et al. , 2016Umetsu et al. 2014Umetsu et al. , 2018Zitrin et al. 2015;Czakon et al. 2015). They developed a detection algorithm for gas density perturbations in cool cores and analyzed X-ray residual image characteristics after subtracting their global profile of the Chandra Xray brightness distribution, finding that all clusters in their sample have at least a pair of positive and negative excess regions. ...
We present an ensemble X-ray analysis of systematic perturbations in the central hot gas properties for a sample of 28 nearby strong cool-core systems selected from the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS). We analyze their cool-core features observed with the Chandra X-ray Observatory. All individual systems in our sample exhibit at least a pair of positive and negative excess perturbations in the X-ray residual image after subtracting the global brightness profile. We extract and analyze X-ray spectra of the intracluster medium (ICM) in the detected perturbed regions. To investigate possible origins of the gas perturbations, we characterize thermodynamic properties of the ICM in the perturbed regions and characterize their correlations between positive and negative excess regions. The best-fit relations for temperature and entropy show a clear offset from the one-to-one relation, $T_\mathrm{neg}/T_\mathrm{pos}=1.20^{+0.04}_{-0.03}$ and $K_\mathrm{neg}/K_\mathrm{pos}=1.43\pm 0.07$, whereas the best-fit relation for pressure is found to be remarkably consistent with the one-to-one relation $P_\mathrm{neg}=P_\mathrm{pos}$, indicating that the ICM in the perturbed regions is in pressure equilibrium. These observed features in the HIFLUGCS sample are in agreement with the hypothesis that the gas perturbations in cool cores are generated by gas sloshing. We also analyze synthetic observations of perturbed cluster cores created from binary merger simulations, finding that the observed temperature ratio agrees with the simulations, $T_\mathrm{neg}/T_\mathrm{pos}\sim 1.3$. We conclude that gas sloshing induced by infalling substructures plays a major role in producing the characteristic gas perturbations in cool cores. The ubiquitous presence of gas perturbations in cool cores may suggest a significant contribution of gas sloshing to suppressing runaway cooling of the ICM.
... A careful interpretation of lensing, dynamical, and X-ray data based on N-body/hydrodynamical simulations suggests that Cl0024þ1654 (z l ¼ 0:395) is the result of a high-speed, line-of-sight collision of two massive clusters viewed approximately 2-3 Gyr after impact when the gravitational potential has had time to relax in the center, but before the gas has recovered . Similar to the case of Cl0024þ1654, Abell 370 (z l ¼ 0:375) is faint in both X-ray and SZE signals and does not follow the X-ray/SZE observable-mass-scaling relations (see Czakon et al. 2015). N-body/hydrodynamical simulations constrained by lensing, dynamical, X-ray, and SZE observations suggest that Abell 370 is a postmajor merger after the second core passage in the infalling phase, just before the third core passage (Molnar et al. 2020). ...
Weak gravitational lensing of background galaxies provides a direct probe of the projected matter distribution in and around galaxy clusters. Here, we present a self-contained pedagogical review of cluster–galaxy weak lensing, covering a range of topics relevant to its cosmological and astrophysical applications. We begin by reviewing the theoretical foundations of gravitational lensing from first principles, with a special attention to the basics and advanced techniques of weak gravitational lensing. We summarize and discuss key findings from recent cluster–galaxy weak-lensing studies on both observational and theoretical grounds, with a focus on cluster mass profiles, the concentration–mass relation, the splashback radius, and implications from extensive mass-calibration efforts for cluster cosmology.
