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An analytic calculation is made of the effect of plasma density fluctuations on some spectroscopic diagnostics commonly used in the study of HII regions and planetary nebulae. To permit an analytic treatment, attention is restricted to the…

Solar and Stellar Astrophysics · Physics 2019-10-21 Steven R. Spangler , Brandon M. Bergerud , Kara M. Beauchamp

For atoms embedded in dense plasma, the plasma screening effects will greatly alter their structure and dynamics, and then determine the radiation transport properties of the plasma. In the present work, a new statistical model is proposed…

Plasma Physics · Physics 2020-11-25 Fuyang Zhou , Yizhi Qu , Junwen Gao , Yulong Ma , Yong Wu , Jianguo Wang

Relativistically broadened and redshifted 6.4 -- 6.9 keV iron K lines are observed from many accretion powered objects, including X-ray binaries and active galactic nuclei (AGN). Existence of gas close to the central engine implies large…

High Energy Astrophysical Phenomena · Physics 2021-02-24 T. Kallman , M. Bautista , J. Deprince , J. A. Garcia , C. Mendoza , A. Ogorzalek , P. Palmeri , P. Quinet

Line ratio of O IV 1407.3 \AA/1401.1 \AA\- is calculated using mostly our own atomic and collisional data. Energy levels and oscillator strengths needed for this calculation have been calculated using a Hartree-Fock relativistic (HFR)…

Solar and Stellar Astrophysics · Physics 2015-06-17 Nabil Ben Nessib , Norah Alonizan , Rabia Qindeel , Sylvie Sahal-Bréchot , Milan S. Dimitrijević

[Abridged] Photoionization, whether by starlight or other sources, has difficulty in accounting for the observed spectra of the optical filaments that often surround central galaxies in large clusters. Our first paper examined whether…

The quality of data taken at RHIC and LHC as well as the success and sophistication of computational models for the description of ultra-relativistic heavy-ion collisions have advanced to a level that allows for the quantitative extraction…

Nuclear Theory · Physics 2018-03-14 Steffen A. Bass , Jonah E. Bernhard , J. Scott Moreland

The emission line ratios [OIII]5007/H-beta and [NII]6584/H-alpha have been adopted as an empirical way to distinguish between the fundamentally different mechanisms of ionization in emission-line galaxies. However, detailed interpretation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Sherry C. C. Yeh , Silvia Verdolini , Mark R. Krumholz , Christopher D. Matzner , Alexander G. G. M. Tielens

A model for ionization and recombination collisions in a multifluid plasma is formulated using the framework introduced in previous work [{Phys. Plasmas} \textbf{22}, 093512 (2015)]. The exchange source terms for density, momentum and…

Plasma Physics · Physics 2016-06-22 H. P. Le , J. -L. Cambier

We revisit a recently proposed scheme [M.F. Ciappina et al 2019 Phys. Rev. A 99 043405] for accurate measurement of electromagnetic radiation intensities in a focus of high-power laser beams. The method is based on the observation of…

Atomic Physics · Physics 2020-02-19 M. F. Ciappina , S. V. Popruzhenko

We present the soft X-ray spectrum of the LINER galaxy M81 from a long observation with the XMM-Newton RGS. As well as continuum emission from the active nucleus, the spectrum shows emission lines from multi temperature collisionally…

Astrophysics · Physics 2007-05-23 M. J. Page , A. A. Breeveld , R. Soria , K. Wu

The He I line at 1.08 $\mu$m is a valuable tracer of atmospheric escape in exoplanet atmospheres. We expand past networks used to predict the absorbing He(2$^3S$) by including, firstly, processes that involve H$_2$ and some molecular ions…

Earth and Planetary Astrophysics · Physics 2025-06-18 Antonio García Muñoz

Absorption lines from the molecules OH+, H2O+, and H3+ have been observed in a diffuse molecular cloud along a line of sight near W51 IRS2. We present the first chemical analysis that combines the information provided by all three of these…

Astrophysics of Galaxies · Physics 2015-06-11 Nick Indriolo , D. A. Neufeld , M. Gerin , T. R. Geballe , J. H. Black , K. M. Menten , J. R. Goicoechea

Rich soft X-ray emission lines of highly charged silicon ions (Si VI--Si XII) were observed by irradiating an ultra-intense laser pulse with width of 200 fs and energy of $\sim$90 mJ on the solid silicon target. The high resolution spectra…

Astrophysics · Physics 2009-11-13 G. Y. Liang , G. Zhao , J. Y. Zhong , Y. T. Li , Y. Q. Liu , Q. L. Dong , X. H. Yuan , Z. Jin , J. Zhang

Reactive species produced by atmospheric pressure plasma jets have high application potential in the fields of biomedicine and surface processing. An extensive validation between the simulation results in this work and measurement data from…

Plasma Physics · Physics 2025-05-22 Youfan He , Ralf Peter Brinkmann , Efe Kemaneci , Andrew R. Gibson

Helium ionization plays an important role in the energy balance of the upper chromosphere and transition region. Helium spectral lines are also often used as diagnostics of these regions. We carry out 1D radiation-hydrodynamics simulations…

Solar and Stellar Astrophysics · Physics 2015-06-18 Thomas Peter Golding , Mats Carlsson , Jorrit Leenaarts

In this work we present a study of the strong optical collisional emission lines of Ne and Ar in an heterogeneous sample of ionized gaseous nebulae for which it is possible to derive directly the electron temperature and hence the chemical…

Spectral lines emitted by plasmas provide information about the thermodynamic conditions, the degree of randomness or the interactions prevailing in the medium. Collisions by plasma electrons penetrating the extent of bound-electron…

Atomic Physics · Physics 2019-05-22 Jean-Christophe Pain , Franck Gilleron

Astrophysical shocks or bursts from a photoionizing source can disturb the typical collisional plasma found in galactic interstellar media or the intergalactic medium. The spectrum emitted by this plasma contains diagnostics that have been…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Randall K. Smith , John P. Hughes

Nova-likes such as BZ Cam are high state Cataclysmic Variables showing hard X-ray emission that can be characterized with advective hot flows in the inner accretion disk. We explore Chandra High Energy Transmission Grating (HETG)…

High Energy Astrophysical Phenomena · Physics 2026-04-14 Solen Balman , Eric M. Schlegel , Patrick Godon , Jeremy J. Drake , Edward M. Sion

We present the first comparison of profiles of H et He resonance lines observed by SUMER with theoretical profiles computed with our non-LTE radiative transfer code. We use the H I Lyman-beta, H I Lyman-epsilon, and He I 584 A lines. Our…

Astrophysics · Physics 2007-05-23 N. Labrosse , J. -C. Vial , P. Gouttebroze
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