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Related papers: The Iron Project and Non-LTE stellar modeling

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We describe a new methodology to analyze the reionization process in numerical simulations: The evo- lution of the reionization is investigated by focusing on the merger histories of individual HII regions. From the merger tree of ionized…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-10 Jonathan Chardin , Dominique Aubert

The calculation of line widths constitutes theoretical and computational challenges in the calculation of opacities of hot dense plasmas. Opacity models use line broadening approximations that are untested at stellar interior conditions.…

Solar and Stellar Astrophysics · Physics 2016-06-22 M. Krief , A. Feigel , D. Gazit

After becoming ionized, low-density astrophysical plasmas will begin a process of slow recombination. Models for this still have significant uncertainties. The recombination cannot normally be observed in isolation, because the ionization…

The computation of radiative opacity or emissivity of hot dense matter is a challenging task. It requires accounting for an immense number of energy levels and lines across various excitation and ionization states. Whether in local…

Atomic Physics · Physics 2025-09-03 Jean-Christophe Pain , Djamel Benredjem

We present a three-dimensional, fully parallelized, efficient implementation of ionizing UV radiation for smoothed particle hydrodynamics (SPH) including self-gravity. Our method is based on the SPH/tree code VINE. We therefore call it…

Astrophysics · Physics 2009-11-13 M. Gritschneder , T. Naab , A. Burkert , S. Walch , F. Heitsch , M. Wetzstein

The p-process nucleosynthesis can explain proton-rich isotopes that are heavier than iron, which are observed in the Solar System, but discrepancies still persist and important questions concerning the astrophysical site(s) of the p-process…

Solar and Stellar Astrophysics · Physics 2022-05-11 A. Choplin , S. Goriely , R. Hirschi , N. Tominaga , G. Meynet

The r-process, or the rapid neutron-capture process, of stellar nucleosynthesis is called for to explain the production of the stable (and some long-lived radioactive) neutron-rich nuclides heavier than iron that are observed in stars of…

Astrophysics · Physics 2008-11-26 M. Arnould , S. Goriely , K. Takahashi

Partial photoionization cross sections from the ^1S ground and the ^3P metastable states of the Be isoelectronic series to different final states including a number of satellite (ionization plus excitation) channels are studied using the…

Atomic Physics · Physics 2012-05-25 W. -C. Chu , H. -L. Zhou , A. Hibbert , S. T. Manson

Since the last IAU symposium on planetary nebulae (PNe), several deep spectroscopic surveys of the relatively faint optical recombination lines (ORLs) emitted by heavy element ions in PNe and H II regions have been completed. New diagnostic…

Astrophysics · Physics 2009-11-11 X. -W. Liu

We carry out plasma diagnostic analyses for 123 planetary nebulae (PNe) and 42 H II regions using the N II and O II optical recombination lines (ORLs). New effective recombination coefficients for the N II and O II optical recombination…

Astrophysics of Galaxies · Physics 2015-06-12 Ian A. McNabb , Xuan Fang , Xiaowei Liu , Robert J. Bastin , Peter J. Storey

Neutron(n)-capture elements (atomic number Z>30), which can be produced in planetary nebula (PN) progenitor stars via s-process nucleosynthesis, have been detected in nearly 100 PNe. This demonstrates that nebular spectroscopy is a…

Solar and Stellar Astrophysics · Physics 2015-05-30 N. C. Sterling , M. C. Witthoeft , D. A. Esteves , P. C. Stancil , A. L. D. Kilcoyne , R. C. Bilodeau , A. Aguilar

The dynamical evolution of hot optically thin plasmas in the ISM crucially depends on the heating and cooling processes. It is essential to realize that all physical processes that contribute operate on different time scales. In particular…

Astrophysics · Physics 2009-11-07 Dieter Breitschwerdt

We summarize recent results and ongoing activities in mathematical algorithms and computer science methods related to proton computed tomography (pCT) and intensity-modulated particle therapy (IMPT) treatment planning. Proton therapy…

Medical Physics · Physics 2021-08-24 Yair Censor , Keith E. Schubert , Reinhard W. Schulte

The so called "isobar run" or RHIC was designed to compare a number of observables for collisions of $^{96}_{40}Zr$ with those of $^{96}_{44}Ru$, aimed at identification of $Z$-dependent effects. However, as the STAR data have shown with…

Nuclear Theory · Physics 2022-02-09 Edward Shuryak

In the past years we have made great efforts to reduce the statistical and systematic uncertainties in stellar parameter and chemical abundance determinations of early B-type stars. Both the construction of robust model atoms for non-LTE…

Solar and Stellar Astrophysics · Physics 2009-02-18 Maria-Fernanda Nieva , Norbert Przybilla

We present an overview of PION, an open-source software project for solving radiation-magnetohydrodynamics equations on a nested grid, aimed at modelling asymmetric nebulae around massive stars. A new implementation of hybrid OpenMP/MPI…

Using the new version of the photoionization code Titan designed for plane-parallel photoionized thick hot media, which is unprecedented from the point of view of line transfer, we have undertaken a study of the influence of different…

Astrophysics · Physics 2009-11-10 Séverine Coupé , Olivier Godet , A. -M. Dumont , Suzy Collin

Radiation from stars and AGN plays an important role in galaxy formation and evolution, and profoundly transforms the IGM, CGM & ISM. On-the-fly RT has started being incorporated in cosmological simulations, but the complex, evolving…

Astrophysics of Galaxies · Physics 2024-11-20 Bernhard Baumschlager , Sijing Shen , James W. Wadsley

We describe an ab initio and non-perturbative $R$-matrix with time-dependence theory for ultrafast atomic processes in light fields of arbitrary polarization. The theory is applicable to complex, multielectron atoms and atomic ions subject…

Atomic Physics · Physics 2018-12-04 D. D. A. Clarke , G. S. J. Armstrong , A. C. Brown , H. W. van der Hart

We present an extension of TRAPHIC, the method for radiative transfer of ionising radiation in smoothed particle hydrodynamics simulations that we introduced in Pawlik & Schaye (2008). The new version keeps all advantages of the original…

Instrumentation and Methods for Astrophysics · Physics 2011-05-10 Andreas H. Pawlik , Joop Schaye
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