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相关论文: An Improved Descriptor of Cluster Stability. Appli…

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Galaxy clusters, the most massive, dark-matter-dominated, and most recently assembled structures in the Universe, are key tools for probing cosmology. However, uncertainties in scaling relations that connect cluster mass to observables like…

宇宙学与河外天体物理 · 物理学 2025-09-24 Giulia Cerini , Elena Bellomi , Nico Cappelluti , Sabina Khizroev , Erwin T. Lau , Priyamvada Natarajan , John ZuHone

I report the current status on the determinations of the baryon fractions and dynamical/lensing masses of galaxy clusters as well as the $\sigma$ - $T$ relationship, making use of all the published data in literature which include 304…

天体物理学 · 物理学 2007-05-23 Xiang-Ping Wu

The level of mass segregation in the core of globular clusters has been previously proposed as a potential indicator of the dynamical constituents of the system, such as presence of a significant population of stellar-mass black holes…

星系天体物理 · 物理学 2019-03-27 Ruggero de Vita , Michele Trenti , Morgan MacLeod

Recently de Marchi, Paresce & Pulone (2007) studied a sample of twenty globular clusters and found that all clusters with high concentrations have steep stellar mass-functions while clusters with low concentration have comparatively shallow…

天体物理学 · 物理学 2009-11-13 Michael Marks , Pavel Kroupa , Holger Baumgardt

The dynamical mass of clusters of galaxies, calculated in terms of modified Newtonian dynamics, is a factor of two or three times smaller than the Newtonian dynamical mass but remains significantly larger than the observed baryonic mass in…

天体物理学 · 物理学 2009-11-13 R. H. Sanders

We have used density functional perturbation theory to investigate the stiffness of interatomic bonds in small clusters of Si, Sn and Pb. As the number of atoms in a cluster is decreased, there is a marked shortening and stiffening of…

其他凝聚态物理 · 物理学 2007-05-23 Raghani Pushpa , Umesh Waghmare , Shobhana Narasimhan

Based on a recently introduced metric for measuring distances between configurations, we in- troduce distance-energy (DE) plots to characterize the potential energy surface (PES) of clusters. Producing such plots is computationally feasible…

原子与分子团簇 · 物理学 2013-11-19 Sandip De , Bastian Schaefer , Ali Sadeghi , Michael Sicher , D. G. Kanhere , Stefan Goedecker

The core structure of galaxy clusters is fundamentally important. Even though self-gravitating systems have no stable equilibrium state due to their negative heat capacity, numerical simulations find density profiles which are universal in…

宇宙学与河外天体物理 · 物理学 2015-06-15 Matthias Bartelmann , Marceau Limousin , Massimo Meneghetti , Robert Schmidt

We use the presently observed number density of large X-ray clusters and the linear mass power spectra to constrain $\sigma_8$ and the redshift distortion parameter $\beta$, in both OCDM and $\Lambda$CDM models. The best fit to the observed…

天体物理学 · 物理学 2009-10-31 Jiun-Huei Proty Wu

The scaling ansatz of Hamilton et al. effectively extends the idea of self-similar scaling to initial power spectra of any generic shape. Applications of this ansatz have provided a semi-empirical analytical description of gravitational…

天体物理学 · 物理学 2007-05-23 Bhuvnesh Jain

We have combined ab initio molecular dynamics with the intrinsic reaction coordinate in order to investigate the mechanisms of stability and pyrolysis of N$_{4}$-- N$_{120}$ fullerene-like nitrogen cages. The stability of the cages was…

材料科学 · 物理学 2020-11-03 Konstantin Katin , Valeriy Merinov , Alexey Kochaev , Savas Kaya , Mikhail Maslov

Using Chandra archival data, we quantify the evolution of cluster morphology with redshift. Clusters form and grow through mergers with other clusters and groups, and the amount of substructure in clusters in the present epoch and how…

天体物理学 · 物理学 2009-11-10 Tesla E. Jeltema , Claude R. Canizares , Mark W. Bautz , David A. Buote

(abridged)We use a sample of ~200,000 galaxies drawn from the Sloan Digital Sky Survey to study how clustering depends on properties such as stellar mass (M*), colour (g-r), 4000A break strength (D4000), concentration index (C), and stellar…

天体物理学 · 物理学 2009-09-25 Cheng Li , Guinevere Kauffmann , Y. P. Jing , Simon D. M. White , Gerhard Boerner , F. Z. Cheng

We investigate the large-scale distribution of galaxy clusters taken from several X-ray catalogs. Different statistics of clustering like the conditional correlation function (CCF) and the minimal spanning tree (MST) as well as void…

天体物理学 · 物理学 2008-05-16 A. V. Tikhonov , A. I. Kopylov , S. Gottlober , G. Yepes

Observations and N-body simulations both support a simple relation for the disruption time of a cluster as a function of its mass of the form: t_dis = t_4 * (M/10^4 Msun)^gamma. The scaling factor t_4 seems to depend strongly on the…

天体物理学 · 物理学 2007-05-23 M. Gieles , H. Baumgardt , N. Bastian , H. J. G. L. M. Lamers

Model selection is a major challenge in non-parametric clustering. There is no universally admitted way to evaluate clustering results for the obvious reason that no ground truth is available. The difficulty to find a universal evaluation…

机器学习 · 计算机科学 2023-05-18 Alex Mourer , Florent Forest , Mustapha Lebbah , Hanane Azzag , Jérôme Lacaille

Clustering provides a common means of identifying structure in complex data, and there is renewed interest in clustering as a tool for the analysis of large data sets in many fields. A natural question is how many clusters are appropriate…

数据分析、统计与概率 · 物理学 2007-05-23 Susanne Still , William Bialek

The radiative cooling rates of C$_N^+$ clusters ($N = 9, 11, 12, 17-27$) have been measured in the ultrahigh vacuum of an electrostatic storage ring to values on the order of $10^4$ s$^{-1}$. The rates were measured as a competing channel…

The open quantum system eigenstate in the vicinity of low-energy decay channel may mimic its features, in particular the characteristic clustering properties of the decay channel. This generic mechanism of clusterization, the so-called…

核理论 · 物理学 2024-11-08 J. P. Linares Fernandez , N. Michel , M. Płoszajczak

Nuclear Star Clusters (NSCs) are often present in spiral galaxies as well as resolved Stellar Nuclei (SNi) in elliptical galaxies centres. Ever growing observational data indicate the existence of correlations between the properties of…

星系天体物理 · 物理学 2014-09-22 Manuel Arca-Sedda , Roberto Capuzzo-Dolcetta