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We develop the theory of interstellar scintillation as caused by an irregular plasma having a power-law spatial density spectrum with a spectral exponent of 4 corresponding to a medium with abrupt changes in its density. An ``outer scale''…

Astrophysics · Physics 2009-10-31 Hendrik Lambert , Barney Rickett

The interstellar medium (ISM) is ubiquitously turbulent across many physically distinct environments within the Galaxy. Turbulence is key in controlling the structure and dynamics of the ISM, regulating star formation, and transporting…

Measurements of pulsar flux densities are of great importance for understanding the pulsar emission mechanism and for predictions of pulsar survey yields and the pulsar population at large. Typically these flux densities are determined from…

Astrophysics of Galaxies · Physics 2015-08-26 M. Kuniyoshi , J. P. W. Verbiest , K. J. Lee , B. Adebahr , M. Kramer , A. Noutsos

$\textit{Herschel}$ observations of far infrared N$^+$ emission lines have demonstrated that dense plasma, with $n_e\sim30\,{\rm cm^{-3}}$, is ubiquitous in the inner Galactic plane. By combining the information from $\textit{Herschel}$…

Astrophysics of Galaxies · Physics 2022-05-03 Marisa Geyer , Mark Walker

The radio frequency 1.4 GHz transition of the atomic hydrogen is one of the important tracers of the diffuse neutral interstellar medium. Radio astronomical observations of this transition, using either a single dish telescope or an array…

Astrophysics of Galaxies · Physics 2016-08-29 Nirupam Roy

Diffuse Galactic light has been observed in the optical since the 1930s. We propose that, when observed in the optical with deep imaging surveys, it can be used as a tracer of the turbulent cascade in the diffuse interstellar medium (ISM),…

Astrophysics of Galaxies · Physics 2016-08-31 M. -A. Miville-Deschenes , P. -A. Duc , F. Marleau , J. -C. Cuillandre , P. Didelon , S. Gwyn , E. Karabal

Diffuse interstellar bands (DIBs) hold a lot of information about the state and the structure of the ISM. Structure can most directly be observed by extensive spectroscopic surveys, including surveys of stars where DIBs are especially…

Astrophysics of Galaxies · Physics 2017-05-10 Janez Kos

The filamentary structure of the molecular interstellar medium and the potential link of this morphology to star formation have been brought into focus recently by high resolution observational surveys. An especially puzzling matter is that…

Astrophysics of Galaxies · Physics 2016-04-20 Evangelia Ntormousi , Patrick Hennebelle , Philippe André , Jacques Masson

Refractive Interstellar Scintillation (RISS) effects on pulsar signals are powerful techniques for discriminating between different models that have been proposed for the power spectrum of plasma density fluctuations in the Interstellar…

Astrophysics · Physics 2007-05-23 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao

This two-part review summarizes interstellar turbulence and its implications. The first part begins with diagnostics and energy sources. Turbulence theory is considered in detail, including the basic fluid equations, solenoidal and…

Astrophysics · Physics 2008-11-26 Bruce G. Elmegreen , John Scalo

We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 carried out using the Ooty Radio Telescope, to investigate the distribution of ionized material in the…

Astrophysics · Physics 2009-10-30 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao

Based on multi-frequency radio polarization survey datasets, we investigate the spectral characteristics of the Galactic interstellar medium (ISM) using the polarization frequency analysis (PFA) method, referred to as polarization variance.…

High Energy Astrophysical Phenomena · Physics 2026-03-19 Ya-Wen Xiao , Jian-Fu Zhang , Alex Lazarian

This chapter reviews the nature of turbulence in the Galactic interstellar medium (ISM) and its connections to the star formation (SF) process. The ISM is turbulent, magnetized, self-gravitating, and is subject to heating and cooling…

Astrophysics of Galaxies · Physics 2017-03-15 Enrique Vazquez-Semadeni

The supernova-driven interstellar medium in star-forming galaxies has Reynolds numbers of the order of $10^{6}$ or even larger. We study, by means of adaptive mesh refinement hydro- and magnetohydrodynamical simulations that cover the full…

Astrophysics · Physics 2007-05-23 M. A. de Avillez , D. Breitschwerdt

Observations of Halpha emission measures and pulsar dispersion measures at high Galactic latitude (|b| > 10 deg) provide information about the density and distribution of the diffuse warm ionized medium (WIM). The diffuse WIM has a…

Astrophysics · Physics 2007-05-23 Alex S. Hill , Ronald J. Reynolds , Robert A. Benjamin , L. Matthew Haffner

The phenomenon of turbulent thermal diffusion in temperature-stratified turbulence causing a non-diffusive turbulent flux of inertial and non-inertial particles in the direction of the turbulent heat flux is found using direct numerical…

Solar and Stellar Astrophysics · Physics 2012-11-28 N. E. L. Haugen , N. Kleeorin , I. Rogachevskii , A. Brandenburg

We investigate the gravitational instability of galactic discs, treating stars and cold interstellar gas as two distinct components, and taking into account the phenomenology of turbulence in the interstellar medium (ISM), i.e. the…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-29 Volker Hoffmann , Alessandro B. Romeo

Gravitational microlensing has become a mature technique for discovering small gravitational lenses in the Universe which are otherwise beyond our detection limits. Similarly, plasma microlensing can help us explore cosmic plasma lenses.…

Astrophysics of Galaxies · Physics 2021-09-28 Xun Shi , Zhu Xu

Interstellar scattering causes pulsar profiles to grow asymmetrically, thus affecting the pulsar timing residuals, and is strongest at lower frequencies. Different Interstellar medium models predict different frequency ($\nu$) and…

High Energy Astrophysical Phenomena · Physics 2019-05-01 Karishma Bansal , G. B. Taylor , Kevin Stovall , Jayce Dowell

Reliable nebular emission line diagnostics are essential for accurately inferring the physical properties (e.g. electron temperature, density, pressure, and metallicity) of H II regions from spectra. When interpreting spectra, it is typical…

Astrophysics of Galaxies · Physics 2026-02-06 Larrance Xing , Nicholas Choustikov , Harley Katz , Alex J. Cameron