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The chemical evolution of galaxies on a cosmological timescale is still a matter of debate despite the increasing number of available data provided by spectroscopic surveys of star-forming galaxies at different redshifts. The fundamental…

Understanding the chemical enrichment of different elements is crucial to gaining a complete picture of galaxy chemical evolution. In this study, we present a new sample of 46 low-redshift, low-mass star-forming galaxies at $M_*\sim…

We analyze the evolution of nitrogen resulting from a set of spiral and irregular galaxy models computed for a large number of input mass radial distributions and with various star formation efficiencies. We show that our models produce a…

天体物理学 · 物理学 2007-11-21 M. Mollá , J. M. Vílchez , A. I. Díaz , M. Gavilán

We investigate the evolution of the star formation rate in the early Galaxy using beryllium and oxygen abundances in metal poor stars. Specifically, we show that stars belonging to two previously identified kinematical classes (the…

天体物理学 · 物理学 2016-08-30 L. Pasquini , D. Galli , R. G. Gratton , P. Bonifacio , S. Randich , G. Valle

We present numerical simulations to describe the nucleosynthesis and evolution of pre-Galactic clouds in a model which is motivated by cold dark matter simulations of hierarchical galaxy formation. We adopt a SN-induced star-formation…

天体物理学 · 物理学 2007-05-23 L. Saleh , T. C. Beers , G. J. Mathews

Chemical abundances in the X-ray halos (also known as the intracluster medium, ICM) of clusters and groups of galaxies can be measured via prominent emission line features in their X-ray spectra. Elemental abundances are footprints of…

高能天体物理现象 · 物理学 2018-12-19 Junjie Mao , J. de Plaa , J. S. Kaastra , Ciro Pinto , Liyi Gu , F. Mernier , Hong-Liang Yan , Yu-Ying Zhang , H. Akamatsu

The proto-Milky Way epoch forms the earliest stars in our Galaxy and sets the initial conditions for subsequent disk formation. Recent observations from APOGEE and H3 surveys showed that the [$\alpha$/Fe] ratio slowly declined between…

星系天体物理 · 物理学 2024-11-11 Boquan Chen , Yuan-Sen Ting , Michael Hayden

Studying the abundances in metal-poor globular clusters is crucial for understanding the formation of the Galaxy and the nucleosynthesis processes in the early Universe. We observed 13 red giant stars from the metal-poor globular cluster…

太阳与恒星天体物理 · 物理学 2025-05-08 Avrajit Bandyopadhyay , Rana Ezzeddine , Vinicius M. Placco , Anna Frebel , David S Aguado , Ian U. Roederer

We test the hypothesis that the classical and ultra-faint dwarf spheroidal satellites of the our Galaxy have been the building blocks of the Galactic halo by comparing their [O/Fe] and [Ba/Fe] vs. [Fe/H] patterns with the ones observed in…

星系天体物理 · 物理学 2018-08-22 E. Spitoni , F. Vincenzo , F. Matteucci , D. Romano

Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. It is argued that cluster metallicity ($\sim 1/3$ solar) should be taken as representative of the low-$z$ universe as a…

天体物理学 · 物理学 2007-05-23 Alvio Renzini

Detailed elemental-abundance patterns of giant stars in the Galactic halo measured by APOGEE-2 have revealed the existence of a unique and significant stellar sub-population of silicon-enhanced ([Si/Fe]$\gtrsim +0.5$) metal-poor stars,…

星系天体物理 · 物理学 2021-01-04 José G. Fernández-Trincado , Timothy C. Beers , Dante Minniti

The {\alpha}-element abundances of the globular cluster (GC) and field star populations of galaxies encode information about the formation of each of these components. We use the E-MOSAICS cosmological simulations of ~L* galaxies and their…

Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. The ratio of the total iron mass in the ICM to the total optical luminosity of the cluster (the iron…

天体物理学 · 物理学 2007-05-23 Alvio Renzini

We have derived element abundances in 310 emission-line galaxies from the Early Data Release of the Sloan Digital Sky Survey (SDSS) for which the [O {\sc iii}] 4363 emission line was detected, allowing abundance determination by direct…

天体物理学 · 物理学 2009-11-10 Y. I. Izotov , G. Stasinska , N. G. Guseva , T. X. Thuan

The innermost portions of the Milky Way's stellar halo have avoided scrutiny until recently. The lack of wide-area survey data, made it difficult to reconstruct an uninterrupted view of the density distribution of the metal-poor stars…

Observations show that galaxies follow a mass-metallicity relation over a wide range of masses. One currently favoured explanation is that less massive galaxies are less able to retain the gas and stellar ejecta and thus may lose the…

天体物理学 · 物理学 2008-11-26 J. Koeppen , C. Weidner , P. Kroupa

The chemical abundances of metal-poor stars provide a great deal of information regarding the individual nucleosynthetic processes that created the observed elements and the overall process of chemical enrichment of the galaxy since the…

星系天体物理 · 物理学 2015-06-17 Heather R. Jacobson , Anna Frebel

We measure the relationship between stellar mass and stellar metallicity, the stellar mass--metallicity relation (MZR), for 1336 star-forming galaxies at $1.6\le z\le3.0$ (<z>=2.2) using rest-frame far-ultraviolet spectra from the…

We derive abundance ratios for nine stars in the relatively high-metallicity bulge globular cluster NGC 6380. We find a mean cluster metallicity between [Fe/H]$= -0.80$ and $-0.73$, with no clear evidence for a variation in iron abundances…

The first galaxies contain stars born out of gas with little or no metals. The lack of metals is expected to inhibit efficient gas cooling and star formation but this effect has yet to be observed in galaxies with oxygen abundance relative…

星系天体物理 · 物理学 2014-10-22 Yong Shi , Lee Armus , George Helou , Sabrina Stierwalt , Yu Gao , Junzhi Wang , Zhi-Yu Zhang , Qiusheng Gu