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Related papers: Modeling He-rich subdwarfs through the Hot-Flasher…

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The current models of early star and galaxy formation are based upon the hierarchical growth of dark matter halos, within which the baryons condense into stars after cooling down from a hot diffuse phase. The latter is replenished by infall…

Astrophysics · Physics 2009-10-31 A. Cavaliere , R. Giacconi , N. Menci

In this review I give a summary of the state-of-the-art for what concerns the chemo-dynamical numerical modelling of galaxies in general and of dwarf galaxies in particular. In particular, I focus my attention on (i) initial conditions;…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 S. Recchi

Context: Turbulent deflagrations of Chandrasekhar mass White Dwarfs are commonly used to model Type Ia Supernova explosions. In this context, rapid rotation of the progenitor star is plausible but has so far been neglected. Aims: The aim of…

High Energy Astrophysical Phenomena · Physics 2015-05-14 J. M. M. Pfannes , J. C. Niemeyer , W. Schmidt , C. Klingenberg

We have used the Spitzer Space Telescope to study the dust properties of a sample of star-forming dwarf galaxies. The differences in the mid-infrared spectral energy distributions for these galaxies which, in general, are low metallicity…

We present an update of our low-resolution spectroscopic follow-up and model atmosphere analysis of hot subdwarf stars from the Galaxy Evolution Explorer (GALEX) survey. Targets were selected on the basis of colour indices calculated from…

Solar and Stellar Astrophysics · Physics 2012-12-06 Péter Németh , Adéla Kawka , Stéphane Vennes

Globular clusters are ideal laboratories to study the evolution of low-mass stars. In this work we concentrate on three types of hot stars observed in globular clusters: horizontal branch stars, UV bright stars, and white dwarfs. After…

Astrophysics · Physics 2009-11-06 S. Moehler

A numerical double burst model of the chemical evolution of gas-rich dwarf galaxies has been developed. The model is fitted to a sample of N/O, O/H, Y and gas fraction observations, where N/O and O/H are the relative abundances by number of…

Astrophysics · Physics 2015-06-24 Thommy I. Larsen , Jesper Sommer-Larsen , Bernard E. J. Pagel

We present 3D hydrodynamic simulations aimed at studying the dynamical and chemical evolution of the interstellar medium in dwarf spheroidal galaxies. This evolution is driven by the explosions of Type II and Type Ia supernovae, whose…

Astrophysics · Physics 2009-11-11 A. Marcolini , A. D'Ercole , F. Brighenti , S. Recchi

Context. The study of old, metal-poor stars deepens our knowledge on the early stages of the universe. In particular, the study of these stars gives us a valuable insight into the masses of the first massive stars and their emission of…

Solar and Stellar Astrophysics · Physics 2021-10-04 A. Matas Pinto , M. Spite , E. Caffau , P. Bonifacio , L. Sbordone , T. Sivarani , M. Steffen , F. Spite , P. Francois , P. Di Matteo

We use the self-consistent model technique developed by Mart\'in-Manj\'on et al. (2008) that combines the chemical evolution with stellar population synthesis and photo-ionization codes, to study the star formation scenarios capable of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 M. L. Martín-Manjón , M. Mollá , A. I. Díaz , R. Terlevich

Magnetic fields with strengths ranging from 300 to 500 kG have recently been discovered in a group of four extremely similar helium-enriched hot subdwarf (He-sdO) stars. Besides their strong magnetic fields, these He-sdO stars are…

Solar and Stellar Astrophysics · Physics 2024-11-13 M. Dorsch , C. S. Jeffery , A. Philip Monai , C. A. Tout , E. J. Snowdon , I. Monageng , L. J. A. Scott , B. Miszalski , V. M. Woolf

We are exploring galaxy evolution in low density environments exploiting smooth particle hydrodynamic simulations including chemo-photometric implementation. From a large grid of simulations of galaxy encounters and mergers starting from…

Astrophysics of Galaxies · Physics 2020-01-08 Paola Mazzei , Roberto Rampazzo , Antonietta Marino , Ginevra Trinchieri , Michela Uslenghi , Anna Wolter

Utilizing low-luminosity star-forming systems discovered in the H$\alpha$ Dots survey, we present spectroscopic observations undertaken using the KPNO 4m telescope for twenty-six sources. With determinations of robust, "direct"-method metal…

Astrophysics of Galaxies · Physics 2022-02-09 Alec S. Hirschauer , John J. Salzer , Nathalie Haurberg , Caryl Gronwall , Steven Janowiecki

We present results of high resolution hydrodynamical simulations of the formation and evolution of dwarf galaxies. Our simulations start from cosmological initial conditions at high redshift. They include metal-dependent cooling, star…

Astrophysics of Galaxies · Physics 2015-05-13 Till Sawala , Cecilia Scannapieco , Umberto Maio , Simon D. M. White

Hypervelocity white dwarfs (HVWDs) are stellar remnants moving at speeds exceeding the Milky Way's escape velocity. The origins of the fastest HVWDs are enigmatic, with proposed formation scenarios facing challenges explaining both their…

High Energy Astrophysical Phenomena · Physics 2025-10-07 Hila Glanz , Hagai B. Perets , Aakash Bhat , Ruediger Pakmor

Delayed detonation in an exploding white dwarf, which propagates from an off-center transition point, rather than from a spherical transition shell, is described and simulated. The differences between the results of 2D simulations and the…

Astrophysics · Physics 2009-10-31 Eli Livne

Properties of nearby dwarf galaxies are briefly discussed. Dwarf galaxies vary widely in their star formation histories, the ages of their subpopulations, and in their enrichment history. Furthermore, many dwarf galaxies show evidence for…

Astrophysics · Physics 2009-10-31 Eva K. Grebel

The so-called ``G-dwarf problem'' emerged in the 1960's when it was noticed that the observed metal distribution of nearby stars differs from what is expected in simple models of the evolution of the Galaxy. We have determined metallicities…

Astrophysics · Physics 2009-10-31 Eira Kotoneva , Chris Flynn

Most numerical simulations of galaxy formation and evolution are unable to properly resolve the turbulent cascade at or below the resolution scale and turbulence models are required to capture the motion of eddies on those unresolved…

Astrophysics of Galaxies · Physics 2024-07-23 Ulrich P. Steinwandel , Douglas Rennehan , Matthew E. Orr , Drummond B. Fielding , Chang-Goo Kim

Masses are a fundamental parameter, but they are not well known for most hot subdwarfs. In general, the mass of a hot subdwarf is derived with asteroseismology or dynamical methods, for which it is often difficult to obtain the necessary…

Solar and Stellar Astrophysics · Physics 2009-10-08 X. Zhang , X. Chen , Z. Han