scholarly journals Using the cluster mass function from weak lensing to constrain neutrino masses

2007 ◽  
Vol 75 (8) ◽  
Author(s):  
Jostein R. Kristiansen ◽  
Øystein Elgarøy ◽  
Håkon Dahle
Keyword(s):  
Mass Function ◽  
Weak Lensing ◽  
Neutrino Masses ◽  
Cluster Mass

scholarly journals Cluster counts: Calibration issue or new physics?

2018 ◽  
Vol 620 ◽  
pp. A78 ◽  
Author(s):  
Ziad Sakr ◽  
Stéphane Ilić ◽  
Alain Blanchard ◽  
Jamal Bittar ◽  
Wehbeh Farah
Keyword(s):  
Free Parameter ◽  
Growth Index ◽  
Mass Function ◽  
New Physics ◽  
Neutrino Masses ◽  
Acoustic Oscillations ◽  
X Ray ◽  
Cluster Mass ◽  
Massive Neutrinos ◽  
Mass Calibration

In recent years, the amplitude of matter fluctuations inferred from low-redshift probes has been found to be generally lower than the value derived from cosmic microwave background (CMB) observations in the ΛCDM model. This tension has been exemplified by Sunyaev-Zel’dovich and X-ray cluster counts which, when using theirPlanckstandard cluster mass calibration, yield a value ofσ8, appreciably lower than estimations based on the latestPlanckCMB measurements. In this work we examine whether non-minimal neutrino masses can alleviate this tension substantially. We used the cluster X-ray temperature distribution function derived from a flux-limited sample of local X-ray clusters, combined withPlanckCMB measurements. These datasets were compared to ΛCDM predictions based on recent mass function, adapted to account for the effects of massive neutrinos. Treating the clusters mass calibration as a free parameter, we examined whether the data favours neutrino masses appreciably higher than the minimal 0.06 eV value. Using Markov chain Monte Carlo methods, we found no significant correlation between the mass calibration of clusters and the sum of neutrino masses, meaning that massive neutrinos do not noticeably alleviate the above-mentionedPlanckCMB–clusters tension. The addition of other datasets (baryon acoustic oscillations and Ly-α) reinforces those conclusions. As an alternative possible solution to the tension, we introduced a simple, phenomenological modification of gravity by letting the growth indexγvary as an additional free parameter. We find that the cluster mass calibration is robustly correlated with theγparameter, insensitively to the presence of massive neutrinos or/and additional data used. We conclude that the standardPlanckmass calibration of clusters, if consolidated, would represent evidence for new physics beyond ΛCDM with massive neutrinos.

scholarly journals An optical observational cluster mass function at z ∼ 1 with the ORELSE survey

2021 ◽  
Vol 502 (3) ◽  
pp. 3942-3954
Author(s):  
D Hung ◽  
B C Lemaux ◽  
R R Gal ◽  
A R Tomczak ◽  
L M Lubin ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Large Scale ◽  
Near Infrared ◽  
Function Analysis ◽  
Voronoi Tessellation ◽  
Cosmological Parameters ◽  
Mass Range ◽  
Mass Function ◽  
Cluster Mass ◽  
Theoretical Mass

ABSTRACT We present a new mass function of galaxy clusters and groups using optical/near-infrared (NIR) wavelength spectroscopic and photometric data from the Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey. At z ∼ 1, cluster mass function studies are rare regardless of wavelength and have never been attempted from an optical/NIR perspective. This work serves as a proof of concept that z ∼ 1 cluster mass functions are achievable without supplemental X-ray or Sunyaev-Zel’dovich data. Measurements of the cluster mass function provide important contraints on cosmological parameters and are complementary to other probes. With ORELSE, a new cluster finding technique based on Voronoi tessellation Monte Carlo (VMC) mapping, and rigorous purity and completeness testing, we have obtained ∼240 galaxy overdensity candidates in the redshift range 0.55 < z < 1.37 at a mass range of 13.6 < log (M/M⊙) < 14.8. This mass range is comparable to existing optical cluster mass function studies for the local universe. Our candidate numbers vary based on the choice of multiple input parameters related to detection and characterization in our cluster finding algorithm, which we incorporated into the mass function analysis through a Monte Carlo scheme. We find cosmological constraints on the matter density, Ωm, and the amplitude of fluctuations, σ8, of $\Omega _{m} = 0.250^{+0.104}_{-0.099}$ and $\sigma _{8} = 1.150^{+0.260}_{-0.163}$. While our Ωm value is close to concordance, our σ8 value is ∼2σ higher because of the inflated observed number densities compared to theoretical mass function models owing to how our survey targeted overdense regions. With Euclid and several other large, unbiased optical surveys on the horizon, VMC mapping will enable optical/NIR cluster cosmology at redshifts much higher than what has been possible before.

scholarly journals Self-consistent proto-globular cluster formation in cosmological simulations of high-redshift galaxies

2020 ◽  
Vol 493 (3) ◽  
pp. 4315-4332 ◽  
Author(s):  
Xiangcheng Ma ◽  
Michael Y Grudić ◽  
Eliot Quataert ◽  
Philip F Hopkins ◽  
Claude-André Faucher-Giguère ◽  
...  
Keyword(s):  
High Pressure ◽  
Star Formation ◽  
High Redshift ◽  
Cluster Formation ◽  
Mass Function ◽  
Cosmological Simulations ◽  
High Redshift Galaxies ◽  
Cluster Mass ◽  
Formation Efficiency ◽  
Redshift Galaxies

ABSTRACT We report the formation of bound star clusters in a sample of high-resolution cosmological zoom-in simulations of z ≥ 5 galaxies from the Feedback In Realistic Environments project. We find that bound clusters preferentially form in high-pressure clouds with gas surface densities over $10^4\, \mathrm{ M}_{\odot }\, {\rm pc}^{-2}$, where the cloud-scale star formation efficiency is near unity and young stars born in these regions are gravitationally bound at birth. These high-pressure clouds are compressed by feedback-driven winds and/or collisions of smaller clouds/gas streams in highly gas-rich, turbulent environments. The newly formed clusters follow a power-law mass function of dN/dM ∼ M−2. The cluster formation efficiency is similar across galaxies with stellar masses of ∼107–$10^{10}\, \mathrm{ M}_{\odot }$ at z ≥ 5. The age spread of cluster stars is typically a few Myr and increases with cluster mass. The metallicity dispersion of cluster members is ∼0.08 dex in $\rm [Z/H]$ and does not depend on cluster mass significantly. Our findings support the scenario that present-day old globular clusters (GCs) were formed during relatively normal star formation in high-redshift galaxies. Simulations with a stricter/looser star formation model form a factor of a few more/fewer bound clusters per stellar mass formed, while the shape of the mass function is unchanged. Simulations with a lower local star formation efficiency form more stars in bound clusters. The simulated clusters are larger than observed GCs due to finite resolution. Our simulations are among the first cosmological simulations that form bound clusters self-consistently in a wide range of high-redshift galaxies.

scholarly journals A New Model to Predict Weak Lensing Peak Counts

2014 ◽  
Vol 10 (S306) ◽  
pp. 107-109 ◽  
Author(s):  
Chieh-An Lin ◽  
Martin Kilbinger
Keyword(s):  
Gravitational Lensing ◽  
Mass Function ◽  
Weak Lensing ◽  
High Signal ◽  
Dark Matter Halos ◽  
Signal To Noise ◽  
New Approach ◽  
Promising Tool ◽  
Peak Abundance ◽  
Good Agreement

AbstractPeak statistics from weak gravitational lensing have been shown to be a promising tool for cosmology. Here we propose a new approach to predict weak lensing peak counts. For an arbitrary cosmology, we draw dark matter halos from the halo mass function, and calculate the number of peaks from the projected halo mass distribution. This procedure is much faster than time-consuming N-body simulations. By comparing these “fast simulations” to N-body runs, we find that the peak abundance is in very good agreement. Furthermore, our model is able to discriminate cosmologies with different sets of parameters, using high signal-to-noise peaks (≳ 4). This encourages us to examine the optimal combinations of parameters to this approach in the future.

scholarly journals Observational Constraints on the Formation and Evolution of Globular Cluster Systems

2007 ◽  
Vol 3 (S246) ◽  
pp. 394-402
Author(s):  
Stephen E. Zepf
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Cluster System ◽  
Host Galaxy ◽  
Cluster Systems ◽  
Cluster Mass ◽  
Formation And Evolution ◽  
Globular Cluster System

AbstractThis paper reviews some of the observational properties of globular cluster systems, with a particular focus on those that constrain and inform models of the formation and dynamical evolution of globular cluster systems. I first discuss the observational determination of the globular cluster luminosity and mass function. I show results from new very deep HST data on the M87 globular cluster system, and discuss how these constrain models of evaporation and the dynamical evolution of globular clusters. The second subject of this review is the question of how to account for the observed constancy of the globular cluster mass function with distance from the center of the host galaxy. The problem is that a radial trend is expected for isotropic cluster orbits, and while the orbits are observed to be roughly isotropic, no radial trend in the globular cluster system is observed. I review three extant proposals to account for this, and discuss observations and calculations that might determine which of these is most correct. The final subject is the origin of the very weak mass-radius relation observed for globular clusters. I discuss how this strongly constrains how globular clusters form and evolve. I also note that the only viable current proposal to account for the observed weak mass-radius relation naturally effects the globular cluster mass function, and that these two problems may be closely related.

scholarly journals Testing the reliability of fast methods for weak lensing simulations: wl-moka on pinocchio

2020 ◽  
Vol 496 (2) ◽  
pp. 1307-1324
Author(s):  
Carlo Giocoli ◽  
Pierluigi Monaco ◽  
Lauro Moscardini ◽  
Tiago Castro ◽  
Massimo Meneghetti ◽  
...  
Keyword(s):  
Large Scale ◽  
Initial Conditions ◽  
Mass Density ◽  
Cosmological Parameters ◽  
Power Spectra ◽  
Mass Function ◽  
Parametric Models ◽  
Weak Lensing ◽  
Approximate Methods ◽  
Percent Accuracy

ABSTRACT The generation of simulated convergence maps is of key importance in fully exploiting weak lensing by large-scale structure (LSS) from which cosmological parameters can be derived. In this paper, we present an extension of the pinocchio code that produces catalogues of dark matter haloes so that it is capable of simulating weak lensing by Modify LSS into Large Scale Structures (LSS). Like wl-moka, the method starts with a random realization of cosmological initial conditions, creates a halo catalogue and projects it on to the past light-cone, and paints in haloes assuming parametric models for the mass density distribution within them. Large-scale modes that are not accounted for by the haloes are constructed using linear theory. We discuss the systematic errors affecting the convergence power spectra when Lagrangian perturbation theory at increasing order is used to displace the haloes within pinocchio, and how they depend on the grid resolution. Our approximate method is shown to be very fast when compared to full ray-tracing simulations from an N-body run and able to recover the weak lensing signal, at different redshifts, with a few percent accuracy. It also allows for quickly constructing weak lensing covariance matrices, complementing pinocchio’s ability of generating the cluster mass function and galaxy clustering covariances and thus paving the way for calculating cross-covariances between the different probes. This work advances these approximate methods as tools for simulating and analysing survey data for cosmological purposes.

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