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High quality X-ray spectra of NGC 4636 are obtained with ASCA. Theoretical models are found unable to reproduce the data in the Fe-L line region. Spectral data above 1.4 keV indicate that Mg to Si abundance ratio is $\sim 1$ solar. Assuming…

天体物理学 · 物理学 2009-10-30 Kyoko Matsushita , Kazuo Makishima , Etsuko Rokutanda , Noriko Y. Yamasaki , Takaya Ohashi

The abundance of iron is measured from emission line complexes at 6.65 keV (Fe line) and 8 keV (Fe/Ni line) in {\em RHESSI} X-ray spectra during solar flares. Spectra during long-duration flares with steady declines were selected, with an…

太阳与恒星天体物理 · 物理学 2015-06-03 K. J. H. Phillips , B. R. Dennis

We test the performance of our analysis technique for integrated-light spectra by applying it to seven well-studied Galactic GCs that span a wide range of metallicities. Integrated-light spectra were obtained by scanning the slit of the…

太阳与恒星天体物理 · 物理学 2017-05-10 S. S. Larsen , J. P. Brodie , J. Strader

We present a new set of stellar interior and synthesis models for predicting the integrated emission from stellar populations in star clusters and galaxies of arbitrary age and metallicity. This work differs from existing spectral synthesis…

天体物理学 · 物理学 2009-11-10 Raul Jimenez , James MacDonald , James Dunlop , Paolo Padoan , John Peacock

We present chemical abundances of red giant branch (RGB) stars in the dwarf spheroidal (dSph) satellite system of Andromeda (M31), using spectral synthesis of medium resolution (R $\sim 6000$) spectra obtained with the Keck II telescope and…

The combination of photometry, spectroscopy and spectropolarimetry of the chemically peculiar stars often aims to study the complex physical phenomena such as stellar pulsation, chemical inhomogeneity, magnetic field and their interplay…

太阳与恒星天体物理 · 物理学 2017-01-25 Santosh Joshi , Eugene Semenko , A. Moiseeva , Kaushal Sharma , Y. C. Joshi , M. Sachkov , Harinder P. Singh , Yerra Bharat Kumar

I present a review of chemical evolution models of the solar neighborhood. I give special attention to the necessary ingredients to reproduce the observed [Xi/Fe] ratios in nearby metal and super metal rich stars, and to the chemical…

天体物理学 · 物理学 2007-05-23 L. Carigi

The ratio of $\alpha$-elements to iron in galaxies holds valuable information about the star formation history since their enrichment occurs on different timescales. The fossil record of stars in galaxies has mostly been excavated for…

星系天体物理 · 物理学 2022-01-19 Andrea Gebek , Jorryt Matthee

Models of stellar spectra are necessary for interpreting light from individual stars, planets, integrated stellar populations, nebulae, and the interstellar medium. We provide a comprehensive and homogeneous collection of synthetic spectra…

太阳与恒星天体物理 · 物理学 2018-10-10 Carlos Allende Prieto , Lars Koesterke , Ivan Hubeny , Manuel A. Bautista , Paul S. Barklem , Sultana N. Nahar

The study of stellar parameters of planet-hosting stars, such as metallicity and chemical abundances, help us to understand the theory of planet formation and stellar evolution. Here, we present a catalogue of accurate stellar atmospheric…

太阳与恒星天体物理 · 物理学 2015-03-11 S. Alves , L. Benamati , N. C. Santos , V. Zh. Adibekyan , S. G. Sousa , G. Israelian , J. R. De Medeiros , C. Lovis , S. Udry

Abundances for alpha-elements and Fe in about 150 field subdwarfs and early subgiants with accurate parallaxes and kinematic data are used to discuss the run of abundance ratios in metal-poor stars in the solar neighborhood. Based on…

In this paper we study the very early phases of the evolution of our Galaxy by means of a chemical evolution model which reproduces most of the observational constraints in the solar vicinity and in the disk. We have restricted our analysis…

天体物理学 · 物理学 2016-08-30 Cristina Chiappini , Francesca Matteucci , Timothy Beers , Ken'ichi Nomoto

The aim of this paper is to characterise the abundance patterns of five iron-peak elements (Mn, Fe, Ni, Cu, and Zn) for which the stellar origin and chemical evolution are still debated. We automatically derived iron peak (Mn, Fe, Ni, Cu,…

太阳与恒星天体物理 · 物理学 2017-10-10 Š. Mikolaitis , P. de Laverny , A. Recio-Blanco , V. Hill , C. C. Worley , M. de Pascale

We present UV-extended E-MILES stellar population synthesis models covering the spectral range 1680-50000A at moderately high resolution. We employ the NGSL space-based stellar library to compute spectra of single-age, single-metallicity…

星系天体物理 · 物理学 2016-12-06 A. Vazdekis , M. Koleva , E. Ricciardelli , B. Röck , J. Falcón-Barroso

By adopting the recently empirically derived dependence of $\alpha$-elements on $[\alpha/{\rm Fe}]$ instead of the conventionally applied uniform one, we tested the agreement between stellar model predictions and observations for red giant…

太阳与恒星天体物理 · 物理学 2024-08-28 G. Valle , M. Dell'Omodarme , P. G. Prada Moroni , S. Degl'Innocenti

The upcoming generation of optical spectrographs on four meter-class telescopes, with their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage, will provide high-quality spectra for…

We investigate the evolutionary history of the Universe's metal content focusing on the chemical abundance of several elements (N, O, S, Si, Fe, Cr, Zn) taken from observational data and predictions from chemical evolution models. The…

天体物理学 · 物理学 2007-05-23 Gustavo A. Lanfranchi , Amancio C. S. Friaca

We investigate stellar elemental abundance patterns at z = 0 in 8 low-mass (M_* = 10^6 - 10^9 M_sun) galaxies in the Feedback in Realistic Environments (FIRE-2) cosmological simulations. Using magnesium (Mg) as a representative…

This paper is the 4th in a series describing the latest additions to the BaSTI stellar evolution database, which consists of a large set of homogeneous models and tools for population synthesis studies. Here we present a new set of low and…

天体物理学 · 物理学 2008-12-18 Susan M. Percival , Maurizio Salaris , Santi Cassisi , Adriano Pietrinferni

The scale of alpha-element yields is difficult to predict from theory because of uncertainties in massive star evolution, supernova physics, and black hole formation, and it is difficult to constrain empirically because the impact of higher…

星系天体物理 · 物理学 2023-09-13 David H. Weinberg , Emily J. Griffith , James W. Johnson , Todd A. Thompson