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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Physics and Astronomy Faculty Publications

2014

ISM

Articles 1 - 3 of 3

Full-Text Articles in Physical Sciences and Mathematics

Separation Of The Ribbon From Globally Distributed Energetic Neutral Atom Flux Using The First Five Years Of Ibex Observations, N. A. Schwadron, E. Moebius, S. A. Fuselier, D. J. Mccomas, H. O. Funsten, Paul H. Janzen, Daniel B. Reisenfeld, H. Kucharek, M. A. Lee, K. Fairchild, F. Allegrini, M. Dayeh, G. Livadiotis, M. Reno, M. Bzowski, J. M. Sokol, M. A. Kubiak, E. R. Christian, R. Demajistre, P. Frisch, A. Galli, P. Wurz, M. Gruntman Nov 2014

Separation Of The Ribbon From Globally Distributed Energetic Neutral Atom Flux Using The First Five Years Of Ibex Observations, N. A. Schwadron, E. Moebius, S. A. Fuselier, D. J. Mccomas, H. O. Funsten, Paul H. Janzen, Daniel B. Reisenfeld, H. Kucharek, M. A. Lee, K. Fairchild, F. Allegrini, M. Dayeh, G. Livadiotis, M. Reno, M. Bzowski, J. M. Sokol, M. A. Kubiak, E. R. Christian, R. Demajistre, P. Frisch, A. Galli, P. Wurz, M. Gruntman

Physics and Astronomy Faculty Publications

The Interstellar Boundary Explorer (IBEX) observes the IBEX ribbon, which stretches across much of the sky observed in energetic neutral atoms (ENAs). The ribbon covers a narrow (∼20–50) region that is believed to be roughly perpendicular to the interstellar magnetic field. Superimposed on the IBEX ribbon is the globally distributed flux that is controlled by the processes and properties of the heliosheath. This is a second study that utilizes a previously developed technique to separate ENA emissions in the ribbon from the globally distributed flux. A transparency mask is applied over the ribbon and …


Accurate Determination Of The Free–Free Gaunt Factor – I. Non-Relativistic Gaunt Factors, P. A. M. Van Hoof, R. J. R. Williams, K. Vollk, Marios Chatzikos, Gary J. Ferland, M. Lykins, R. L. Porter, Ye Wang Oct 2014

Accurate Determination Of The Free–Free Gaunt Factor – I. Non-Relativistic Gaunt Factors, P. A. M. Van Hoof, R. J. R. Williams, K. Vollk, Marios Chatzikos, Gary J. Ferland, M. Lykins, R. L. Porter, Ye Wang

Physics and Astronomy Faculty Publications

Modern spectral synthesis codes need the thermally averaged free–free Gaunt factor defined over a very wide range of parameter space in order to produce an accurate prediction for the spectrum emitted by an ionized plasma. Until now no set of data exists that would meet this need in a fully satisfactory way. We have therefore undertaken to produce a table of very accurate non-relativistic Gaunt factors over a much wider range of parameters than has ever been produced before. We first produced a table of non-averaged Gaunt factors, covering the parameter space 10log ϵi = −20 to +10 …


On The Observability Of Optically Thin Coronal Hyperfine Structure Lines, Marios Chatzikos, Gary J. Ferland, R. J. R. Williams, A. C. Fabian May 2014

On The Observability Of Optically Thin Coronal Hyperfine Structure Lines, Marios Chatzikos, Gary J. Ferland, R. J. R. Williams, A. C. Fabian

Physics and Astronomy Faculty Publications

We present CLOUDY calculations for the intensity of coronal hyperfine lines in various environments. We model indirect collisional and radiative transitions, and quantify the collisionally excited line emissivity in the density-temperature phase space. As an observational aid, we also express the emissivity in units of that in the 0.4-0.7 keV band. For most hyperfine lines, knowledge of the X-ray surface brightness and the plasma temperature is sufficient for rough estimates. We find that the radiation fields of both Perseus A and Virgo A can enhance the populations of highly ionized species within 1 kpc. They can also enhance line emissivity …