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We present an analytical and phenomenological model for metal enrichment in halos based on hierarchical structure formation. This model assumes that astration of normal stellar populations along with SNe II already occurs at very high…

Astrophysics · Physics 2009-11-10 Y. -Z. Qian , G. J. Wasserburg

With the advent of large spectroscopic surveys the amount of high quality chemo-dynamical data in the Milky Way (MW) increased tremendously. Accurately and correctly capturing and explaining the detailed features in the high-quality…

The damped Lyman alpha systems seen in the spectra of high redshift QSOs offer the means to determine element abundances in galaxies observed while still at an early stage of evolution. Such measurements, which have only recently come…

Astrophysics · Physics 2016-08-30 Max Pettini , Keith Lipman , Richard W. Hunstead

The chemical abundances of stars in galaxies are a fossil record of the star formation and stellar evolution processes that regulate galaxy formation, including the stellar initial mass function, the fraction and timing of type Ia…

We use the redshift distribution of type-Ia supernovae (SNe) discovered by the Supernova Cosmology Project to constrain the star formation history (SFH) of the Universe and SN Ia progenitor models. Given some of the recent determinations of…

Astrophysics · Physics 2009-11-10 Avishay Gal-Yam , Dan Maoz

The delay time distribution of Type Ia supernovae (the time-dependent rate of supernovae resulting from a burst of star formation) has been measured using different techniques and in different environments. Here, we study in detail the…

High Energy Astrophysical Phenomena · Physics 2019-09-11 E. Heringer , C. Pritchet , M. H. van Kerkwijk

We investigate the chemical properties of local galaxies within a cosmological framework in the hierarchical picture of galaxy formation. To this aim, we use a hierarchical semi-analytic model which includes the contribution from (i) low…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Francesco Calura , Nicola Menci

Although evidence is accumulating that abundance ratios in galaxies are often non-solar, they are far from understood. I resume the current evidence for non-solar abundance ratios, supplementing the recent review by Worthey (1998) with some…

Astrophysics · Physics 2007-05-23 Reynier Peletier

The stellar populations of galaxies hold vital clues to their formation histories. In this paper we present results based on modeling stacked spectra of early-type galaxies drawn from the Sloan Digital Sky Survey (SDSS) as a function of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Charlie Conroy , Genevieve Graves , Pieter van Dokkum

We calculate the evolution of heavy element abundances from C to Zn in the solar neighborhood adopting our new nucleosynthesis yields. Our yields are calculated for wide ranges of metallicity (Z=0-Z_\odot) and the explosion energy (normal…

Astrophysics · Physics 2008-11-26 C. Kobayashi , H. Umeda , K. Nomoto , N. Tominaga , T. Ohkubo

We compute the chemical evolution of the Galactic bulge in the context of an inside-out model for the formation of the Milky Way. The model contains updated stellar yields from massive stars. The main purpose of the paper is to compare the…

Astrophysics · Physics 2009-11-13 Silvia K. Ballero , Francesca Matteucci , Livia Origlia , R. Michael Rich

In stars, metallicity is usually traced using Fe, while in nebulae, O serves as the preferred proxy. Both elements have different nucleosynthetic origins and are not directly comparable. Additionally, in ionized nebulae, Fe is heavily…

Chemical abundance determinations from stellar spectra are challenged by observational noise, limitations in stellar models, and departures from simplifying assumptions. While traditional and supervised machine learning methods have made…

Solar and Stellar Astrophysics · Physics 2025-12-24 Theosamuele Signor , Paula Jofré , Hernan Lira , Sara Vitali , Luis Martí , Nayat Sánchez-Pi

We map the trends of elemental abundance ratios across the Galactic disk, spanning R = 3-15 kpc and midplane distance |Z|= 0-2 kpc, for 15 elements in a sample of 20,485 stars measured by the SDSS/APOGEE survey (O, Na, Mg, Al, Si, P, S, K,…

We present a general phenomenological model for the metallicity distribution (MD) in terms of [Fe/H] for dwarf spheroidal galaxies (dSphs). These galaxies appear to have stopped accreting gas from the intergalactic medium and are fossilized…

Astrophysics of Galaxies · Physics 2015-06-04 Yong-Zhong Qian , Gerald J. Wasserburg

Supernova rates (hypernova, type II, type Ib/c and type Ia) in a particular galaxy depend on the metallicity (i.e. on the galaxy age), on the physics of star formation and on the binary population. In order to study the time evolution of…

Astrophysics · Physics 2009-11-07 E. De Donder , D. Vanbeveren

We present isochrone ages and initial bulk metallicities ($\rm [Fe/H]_{bulk}$, by accounting for diffusion) of 163,722 stars from the GALAH Data Release 2, mainly composed of main sequence turn-off stars and subgiants ($\rm 7000…

According to previous spectral analyses of Wolf-Rayet type central stars, late [WC] subtypes show systematically higher carbon-to-helium abundance ratios than early [WC] subtypes. If this were true, it would rule out that these stars form…

Astrophysics · Physics 2009-06-25 H. Todt , G. Gräfener , W. -R. Hamann

We calculate the mean evolution of the iron-peak abundance ratios [(Cr,Mn,Co,Zn)/Fe] in the Galaxy, using modern supernova and hypernova chemical yields and a Galactic Chemical Evolution code that assumes homogeneous chemical evolution. We…

Astrophysics of Galaxies · Physics 2020-07-01 J. J. Grimmett , Amanda I. Karakas , Alexander Heger , Bernhard Müller , Christopher West

Yttrium (Y), a key s-process element, is commonly used in nucleosynthesis studies and as a Galactic chemical clock when combined with magnesium (Mg). We study the applicability of the previously assumed LTE line formation assumption in Y…

Solar and Stellar Astrophysics · Physics 2023-09-06 Nicholas Storm , Maria Bergemann