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Open cluster members are coeval and share the same initial bulk chemical compositions. Consequently, differences in surface abundances between members of a cluster that are at different evolutionary stages can be used to study the effects…

Aims. The statistical equilibrium of neutral and ionized silicon in the atmospheres of metal-poor stars is discussed. Non-local thermodynamic equilibrium effects are investigated and the silicon abundances in metal-poor stars determined.…

太阳与恒星天体物理 · 物理学 2015-05-13 J. R. Shi , T. Gehren , L. Mashonkina , G. Zhao

The abundance, temperature, and clustering of metals in the intergalactic medium are important parameters for understanding their cosmic evolution and quantifying their impact on cosmological analysis with the Ly $\alpha$ forest. The…

We have derived new detailed abundances of Mg, Ca, and the Fe-group elements Sc through Zn (Z = 21-30) for 37 main sequence turnoff very metal-poor stars ([Fe/H] <= -2.1). We analyzed Keck HIRES optical and near-UV high signal-to-noise…

We carried out observations of the central and 20' east offset regions of the cluster of galaxies Abell 1060 with Suzaku. Spatially resolved X-ray spectral analysis has revealed temperature and abundance profiles of Abell 1060 out to 27' ~…

We present the first large sample of accurate iron abundances and temperatures for clusters at redshifts greater than 0.14. We find that the Fe abundance shows little or no evolution out to redshift 0.3. This and the early formation epoch…

天体物理学 · 物理学 2009-10-30 Richard Mushotzky , Michael Loewenstein

A central drop of ICM Fe abundance has been observed in several cool-core clusters. It has been proposed that this abundance drop may be due, at least partially, to the depletion of Fe into dust grains in the central, high-density regions.…

星系天体物理 · 物理学 2019-04-11 Ang Liu , Meng Zhai , Paolo Tozzi

We examine metal and entropy content in galaxy groups having T_X~0.5-2 keV in cosmological hydrodynamic simulations. Our simulations include a well-constrained prescription for galactic outflows following momentum-driven wind scalings, and…

天体物理学 · 物理学 2009-11-13 Romeel Davé , Benjamin D. Oppenheimer , Suresh Sivanandam

We report the abundances of 30 elements in 23 metal-poor ([Fe/H] <-1.7) giants. These are based on 7774 equivalent widths and spectral synthesis of 229 additional lines. Hyperfine splitting is taken into account when appropriate. Our choice…

天体物理学 · 物理学 2016-08-30 Jennifer A. Johnson

Recent X-ray observations of galaxy clusters show that the distribution of intra-cluster medium (ICM) metallicity is remarkably uniform in space and time. In this paper, we analyse a large sample of simulated objects, from poor groups to…

Stellar evolution calculations with variable abundance ratios were used to gauge the effects on temperatures, luminosities, and lifetimes in various phases. Individual elements C, N, O, Mg, Si, and Fe were included. Most of the effect…

星系天体物理 · 物理学 2022-02-09 Guy Worthey , Xiang Shi , Tathagata Pal , Hyun-chul Lee , Baitian Tang

For the well studied halo star HD 122563 and the four stars in the globular cluster NGC 6397, we determine NLTE abundances of iron using classical plane-parallel model atmospheres. Each star reveals a discrepancy in abundances between the…

太阳与恒星天体物理 · 物理学 2013-03-05 L. Mashonkina , H. -G. Ludwig , A. Korn , T. Sitnova , E. Caffau

This is the second in a series of papers in which we analyze spectra of over 400 K and M giants in Baade's Window, including most of the stars with proper motions measured by Spaenhauer et al. [AJ, 103, 297 (1992)]. In our first paper, we…

天体物理学 · 物理学 2014-10-13 Elaine M. Sadler , R. Michael Rich , D. M. Terndrup

We further study the unusual trend we found at statistically significant levels in some globular clusters, including NGC 3201: a decreasing iron abundance in red giants towards the cluster centers. We first show that recently published new…

星系天体物理 · 物理学 2017-08-09 Valery V. Kravtsov

A catalog compiling the parameters of 346 open clusters, including their metallicities, positions, ages, and velocities has been composed. The elements of the Galactic orbits for 272 of the clusters have been calculated. Spectroscopic…

星系天体物理 · 物理学 2016-02-17 V. A. Marsakov , M. L. Gozha , V. V. Koval' , L. V. Shpigel'

This work measures the evolution of the iron content in galaxy clusters by a rigorous analysis of the data of 130 clusters at 0.1<z<1.3. This task is made difficult by a) the low signal-to-noise ratio of abundance measurements and the upper…

宇宙学与河外天体物理 · 物理学 2015-06-11 S. Andreon

We present the iron abundance and abundance ratios for 18 elements with respect to Fe in a sample of stars with a wide range in luminosity from luminous giants to stars near the turnoff in the globular cluster M5. The analyzed spectra,…

天体物理学 · 物理学 2009-11-07 Solange V. Ramirez , Judith G. Cohen

[ABRIDGED] We report the results of a high-resolution spectroscopic survey of all the stars more luminous than Mv = 6.5 mag within 14.5 pc from the Sun. We derive stellar parameters and perform a preliminary abundance and kinematic analysis…

天体物理学 · 物理学 2016-08-30 Carlos Allende Prieto , Paul S. Barklem , David L. Lambert , Katia Cunha

The Mg/Ne abundance ratio in the quiet Sun is measured in both network and supergranule cell centre regions through EUV spectra from the Coronal Diagnostic Spectrometer on SOHO. Twenty four sets of data over the period 1996 March to 1998…

天体物理学 · 物理学 2009-11-10 P. R. Young

We report further results from a 191 ks Chandra observation of the core of the Perseus cluster, Abell 426. The emission-weighted temperature and abundance structure is mapped detail. There are temperature variations down to ~1 kpc in the…

天体物理学 · 物理学 2008-11-26 J. S. Sanders , A. C. Fabian , S. W. Allen , R. W. Schmidt