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Cosmological simulations find that pockets of star-forming gas could remain pristine up until the Epoch of Reionization (EoR) due to the inhomogeneous nature of metal mixing and enrichment in the early Universe. Such pristine clouds could…

Astrophysics of Galaxies · Physics 2026-04-01 Lisanne van Veenen , Piyush Sharda , Serena Viti , Shyam H. Menon

We present a study of the stellar populations of a sample of 39 local, field early-type galaxies whose HI properties are known from interferometric data. Our aim is to understand whether stellar age and chemical composition depend on the HI…

Astrophysics · Physics 2009-11-13 Paolo Serra , Scott C. Trager , Tom A. Oosterloo , Raffaella Morganti

Early results from JWST suggest that epoch-of-reionization (EoR) galaxies produce copious ionizing photons, which, if they escape efficiently, could cause reionization to occur too early. We study this problem using \jwst\ imaging and prism…

The formation and evolution of low-mass stars within dense halos of dark matter (DM) leads to evolution scenarios quite different from the classical stellar evolution. As a result of our detailed numerical work, we describe these new…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Jordi Casanellas , Ilidio Lopes

The interstellar medium of galaxies is composed of multiple phases, including molecular, atomic, and ionized gas, as well as dust. Stars are formed within this medium from cold molecular gas clouds, which collapse due to their gravitational…

Astrophysics of Galaxies · Physics 2024-06-03 Jonathan Freundlich

The radial profiles of gas, stars, and far ultraviolet radiation in 20 dwarf Irregular galaxies are converted to stability parameters and scale heights for a test of the importance of two-dimensional (2D) instabilities in promoting star…

Astrophysics of Galaxies · Physics 2015-06-03 Bruce G. Elmegreen , Deidre A. Hunter

We address the cosmological evolution of violent gravitational instability in high-redshift, massive, star-forming galactic discs. To this aim, we integrate in time the equations of mass and energy conservation under self-regulated…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Marcello Cacciato , Avishai Dekel , Shy Genel

We calculate the evolution of zero-metallicity Population III (Pop III) stars whose mass grows from the initial mass of $\sim 1M_{\odot}$ by accreting the surrounding gases. Our calculations cover a whole evolutionary stages from the…

Solar and Stellar Astrophysics · Physics 2009-11-18 Takuya Ohkubo , Ken'ichi Nomoto , Hideyuki Umeda , Naoki Yoshida , Sachiko Tsuruta

We present the first set of a new generation of models of massive stars of solar composition extending between 13 and 120 \msun, computed with and without the effects of rotation. We included two instabilities induced by rotation, namely…

Solar and Stellar Astrophysics · Physics 2012-12-13 Alessandro Chieffi , Marco Limongi

We describe the first three-dimensional simulation of the gravitational collapse of a massive, rotating molecular cloud that includes heating by both non-ionizing and ionizing radiation. We find that as the first protostars gain sufficient…

Solar and Stellar Astrophysics · Physics 2010-02-23 Thomas Peters , Robi Banerjee , Ralf S. Klessen , Mordecai-Mark Mac Low , Roberto Galvan-Madrid , Eric Keto

The temperature in most parts of a protoplanetary disk is determined by irradiation from the central star. Numerical experiments of Watanabe \& Lin (2008) suggested that such disks, also called `passive disks', suffer from a thermal…

Earth and Planetary Astrophysics · Physics 2021-12-22 Yanqin Wu , Yoram Lithwick

Star formation occurs within dense regions of giant molecular clouds (GMCs), however, exactly how gas collects and evolves to form individual stars and what role dense cores play remains unclear. We use the Lagrangian cell information in…

Astrophysics of Galaxies · Physics 2026-04-09 Ananya Kaalva , Stella S. R. Offner , Nina Filippova , Michael Y. Grudic

The history of the transition from a neutral intergalactic medium (IGM) to one that is almost fully ionized can reveal the character of cosmological ionizing sources. We study the evolution of the volume filling factor of HII and HeIII…

Astrophysics · Physics 2009-10-30 Piero Madau , Francesco Haardt , Martin J. Rees

Population-III (Pop-III) starformation (SF) is thought to be quenched when the metallicity of the star-forming gas reaches a critical level. At high z, when the general intergalactic medium (IGM) was enriched with metals, the fraction of…

Astrophysics · Physics 2015-06-24 Stuart Wyithe , Renyue Cen

Photoheating associated with reionization suppressed star formation in low-mass galaxies. Reionization was inhomogeneous, however, affecting different regions at different times. To establish the causal connection between reionization and…

We study cosmological simulations of early structure formation, including non-equilibrium molecular chemistry, metal pollution from stellar evolution, transition from population III (popIII) to population II (popII) star formation,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Umberto Maio , Sadegh Khochfar , Jarrett L. Johnson , Benedetta Ciardi

We study a resistive tearing instability developing in a system evolving through the combined effect of Hall drift in the Electron-MHD limit and Ohmic dissipation. We explore first the exponential growth of the instability in the linear…

High Energy Astrophysical Phenomena · Physics 2016-09-19 Konstantinos N. Gourgouliatos , Rainer Hollerbach

In order to constrain the initial mass function (IMF) of the first generation of stars (Population III), we investigate the fragmentation properties of metal-free gas in the context of a hierarchical model of structure formation. We…

Astrophysics · Physics 2009-10-31 Volker Bromm , Paolo S. Coppi , Richard B. Larson

The first stars continue to elude modern telescopes, but much has been accomplished in observing the glow of the first galaxies. As detection capabilities improve we will eventually resolve these galaxies, but hopes of observing an…

Solar and Stellar Astrophysics · Physics 2015-06-24 T. M. Lawlor , T. R. Young , J. Teffs , J. MacDonald

We use state-of-the-art hydrodynamical simulations combined with a 1D radiative transfer code to assess the extent to which the highly ionized regions observed close to z~6 quasars, which we refer to as near-zones, can constrain the…

Astrophysics · Physics 2008-11-26 James S. Bolton , Martin G. Haehnelt