English
Related papers

Related papers: Astrophysical line diagnosis requires non-linear d…

200 papers

The five J$\Pi$ levels within a $np^2$ or $np^4$ ground state complex provide an excellent testing ground for the comparison of theoretical line ratios with astrophysically observed values, in addition to providing valuable electron…

Earth and Planetary Astrophysics · Physics 2012-04-02 B. M. McLaughlin , Teck-Ghee Lee , J. A. Ludlow , E. Landi , S. D. Loch , M. S. Pindzola , C. P. Ballance

We review X-ray plasma diagnostics based on the line ratios of He-like ions. Triplet/singlet line intensities can be used to determine electronic temperature and density, and were first developed for the study of the solar corona. Since the…

High Energy Astrophysical Phenomena · Physics 2015-03-17 Delphine Porquet , Jacques Dubau , Nicolas Grosso

This review focuses on nuclear reactions in astrophysics and, more specifically, on reactions with light ions (nucleons and alpha particles) proceeding via the strong interaction. It is intended to present the basic definitions essential…

Nuclear Theory · Physics 2015-03-17 T. Rauscher

The solar photospheric Fe abundance has been determined using realistic ab initio 3D, time-dependent, hydrodynamical model atmospheres. The study is based on the excellent agreement between the predicted and observed line profiles directly…

Astrophysics · Physics 2007-05-23 M. Asplund , AA. Nordlund , R. Trampedach , R. F. Stein

We report energy levels, radiative rates (A-values) and lifetimes for the astrophysically-important Be-like ion C III. For the calculations, 166 levels belonging to the $n \le$ 5 configurations are considered and the {\sc grasp}…

Solar and Stellar Astrophysics · Physics 2015-06-24 K. M. Aggarwal , F. P. Keenan

Weak line emission originating in the photosphere is well known from O stars and widely used for luminosity classification. The physical origin of the line emission are NLTE effects, most often optical pumping by far-UV lines. Analogous…

Solar and Stellar Astrophysics · Physics 2015-06-22 Th. Rivinius , M. Shultz , G. A. Wade

We revisit the Galactic chemical evolution of oxygen, addressing the systematic errors inherent in classical determinations of the oxygen abundance that arise from the use of one dimensional hydrostatic (1D) model atmospheres and from the…

Solar and Stellar Astrophysics · Physics 2015-09-11 A. M. Amarsi , M. Asplund , R. Collet , J. Leenaarts

The computationally demanding nature of radiative-hydrodynamical simulations of stellar surface convection warrants an investigation of the sensitivity of the convective structure and spectral synthesis to the numerical resolution and…

Astrophysics · Physics 2007-05-23 M. Asplund , H. -G. Ludwig , AA. Nordlund , R. F. Stein

We show that if the laser is intense enough, it may always ionize an atom or induce transitions between discrete energy levels of the atom, no matter what is its frequency. It means in the quantum transition of an atom interacting with an…

Quantum Physics · Physics 2007-05-23 Qi-Ren Zhang

We investigate the impact of 3D hydrodynamical model atmospheres of red giant stars at different metallicities on the formation of spectral lines of a number of ions and molecules. We carry out realistic 3D simulations of surface convection…

Astrophysics · Physics 2009-11-13 Remo Collet , Martin Asplund , Regner Trampedach

Modelling of massive stars and supernovae (SNe) plays a crucial role in understanding galaxies. From this modelling we can derive fundamental constraints on stellar evolution, mass-loss processes, mixing, and the products of…

Atomic Physics · Physics 2016-09-07 N. B. Tyndall , C. A. Ramsbottom , C. P. Ballance , A. Hibbert

Nitrogen is an important element in various fields of stellar and Galactic astronomy, and the solar nitrogen abundance is crucial as a yardstick for comparing different objects in the cosmos. In order to obtain a precise and accurate value…

Solar and Stellar Astrophysics · Physics 2020-04-29 A. M. Amarsi , N. Grevesse , J. Grumer , M. Asplund , P. S. Barklem , R. Collet

We present new atomic data (radiative transitions rates and collision strengths) from large scale calculations and a non-LTE spectral model for Fe III. This model is in very good agreement with observed astronomical emission spectra, in…

Atomic Physics · Physics 2015-05-19 Manuel A. Bautista , Connor P. Ballance , Pascal Quinet

Optical diagnostic diagrams are frequently ambiguous as a test of the photoionization or fast shock models of the narrow line regions of active galaxies. Here, we present a set of UV line ratio diagrams which can discriminate between pure…

Astrophysics · Physics 2009-10-30 M. G. Allen , M. A. Dopita , Z. I. Tsvetanov

In this review, we emphasize the interplay between astrophysical observations, modeling, and nuclear physics laboratory experiments. Several important nuclear cross sections for astrophysics have long been identified e.g.…

Nuclear Experiment · Physics 2016-05-26 Alain Coc , Fairouz Hammache , Juergen Kiener

Intensity mapping experiments survey the spectrum of diffuse line radiation rather than detect individual objects at high signal-to-noise. Spectral maps of unresolved atomic and molecular line radiation contain three-dimensional information…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-19 Eric R. Switzer , Tzu-Ching Chang , Kiyoshi W. Masui , Ue-Li Pen , Tabitha C. Voytek

This paper discusses some features of the spectral line profile theory used in the treatment of measured atomic transitions. It is shown that going beyond the established linear approximation for the spectral line contour in the case of its…

Atomic Physics · Physics 2024-05-03 D. Solovyev , A. Anikin , T. Zalialiutdinov

Properties of hot gas outflows from galaxies are generally measured from associated X-ray line emission assuming that it represents atomic transitions in thermally excited hot gas. X-ray line emission, however, can also arise from the…

Astrophysics of Galaxies · Physics 2015-06-03 Jiren Liu , Q. Daniel Wang , Shude Mao

The origin and chemical composition of ultra high energy cosmic rays is still an open question in astroparticle physics. The observed large-scale isotropy and also direct composition measurements can be interpreted as an extragalactic…

Astrophysics · Physics 2009-11-13 Markus Ahlers

The growth of spectroscopic observations of exoplanetary systems allows the possibility of testing theoretical models and studying the interaction that exoplanetary atmospheres have with the wind and the energetic photons from the star. In…

Earth and Planetary Astrophysics · Physics 2020-09-30 C. Villarreal D'Angelo , A. A. Vidotto , A. Esquivel , M. A. Sgró , T. Koskinen , L. Fossati