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A significant fraction of debris discs consist of a bright ring beyond which extends a wide halo. Such a halo should be made of small grains produced in the ring of parent bodies (PB) and pushed on high-e orbits by radiation pressure. It…

Earth and Planetary Astrophysics · Physics 2023-07-05 Philippe Thebault , Johan Olofsson , Quentin Kral

If dark matter has a large self-interaction scattering cross section, then interactions among dark-matter particles will drive galaxy and cluster halos to become spherical in their centers. Work in the past has used this effect to rule out…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Annika H. G. Peter , Miguel Rocha , James S. Bullock , Manoj Kaplinghat

A relativistic analysis of the polarization properties of light elastically scattered by atomic hydrogen is performed, based on the Dirac equation and second order perturbation theory. The relativistic atomic states used for the…

The distribution of dark matter around galactic or cluster halos has usually been assumed to be approximately isothermal with a non-zero core radius, which is expected to be of the order of the size of the visible matter distribution.…

Astrophysics · Physics 2009-10-22 Ricardo A. Flores , Joel R. Primack

In this paper we calculate the potential for a prolate spheroidal distribution as in a dark matter halo with a radially varying eccentricity. This is obtained by summing up the shell-by-shell contributions of isodensity surfaces, which are…

Astrophysics of Galaxies · Physics 2015-06-15 R. Rathulnath , Chanda J. Jog

We examine the outskirts of galaxy clusters in the C-EAGLE simulations to quantify the `edges' of the stellar and dark matter distribution. The radius of the steepest slope in the dark matter, commonly used as a proxy for the splashback…

The radar scattering properties of realistic aggregate snowflakes have been calculated using the Rayleigh-Gans theory. We find that the effect of the snowflake geometry on the scattering may be described in terms of a single universal…

Atmospheric and Oceanic Physics · Physics 2015-06-26 C. D. Westbrook , R. C. Ball , P. R. Field

We revisit the scattering of surface plasmons by shallow surface defects for both protrusions and indentations of various lengths, which are deemed infinite in one-dimension parallel to the surface. Subwavelength protrusions and…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 Giovanni Brucoli , Luis Martín Moreno

This is the third paper in a series in which we attempt to put constraints on the flattening of dark halos in disk galaxies. For this purpose we need to analyse the observed XV diagrams in edge-on galaxies to accurately measure the radial…

Astrophysics of Galaxies · Physics 2015-05-18 J. C. O'Brien , K. C. Freeman , P. C. van der Kruit

We extend the T-matrix approach to light scattering by spherical particles to some simple cases in which the scatterers are optically anisotropic. Specifically we consider cases in which the spherical particles include radially and…

Optics · Physics 2009-11-07 A. D. Kiselev , V. Yu Reshetnyak , T. J. Sluckin

We present the basics of microlensing and give an overview of the results obtained so far. We also describe a scenario in which dark clusters of MACHOs (Massive Astrophysical Compact Halo Objects) and cold molecular clouds (mainly of $H_2$)…

Astrophysics · Physics 2009-10-31 Ph. Jetzer

Via joint analysis of a calibrated telescopic survey, which found scattering Kuiper Belt objects, and models of their expected orbital distribution, we measure the form of the scattering object's size distribution. Ruling out a single…

Earth and Planetary Astrophysics · Physics 2013-02-01 C. Shankman , B. Gladman , N. Kaib , J. J. Kavelaars , J. -M. Petit

Interstellar grain mantles present in dense interstellar clouds are in constant exchange with the gas phase via accretion and desorption mechanisms such as UV, X-ray photodesorption, cosmic ray induced sputtering, grain thermal…

Astrophysics of Galaxies · Physics 2018-10-24 E. Dartois , M. Chabot , T. Id Barkach , H. Rothard , B. Augé , A. N. Agnihotri , A. Domaracka , P. Boduch

The rate of dark matter-electron scattering depends on the underlying velocity distribution of the dark matter halo. Importantly, dark matter-electron scattering is particularly sensitive to the high-velocity tail, which differs…

High Energy Physics - Phenomenology · Physics 2021-02-17 Aria Radick , Anna-Maria Taki , Tien-Tien Yu

We propose a new method to determine the dipole (and quadrupole) component of a distribution of cosmic ray arrival directions, which can be applied when there is partial sky coverage and/or inhomogeneous exposure. In its simplest version it…

Astrophysics · Physics 2009-11-11 Silvia Mollerach , Esteban Roulet

The discrete dipole approximation (DDA) is a popular numerical method for calculating the scattering properties of atmospheric ice crystals. The standard DDA formulation involves the uniform discretization of the underlying volume integral…

Computational Physics · Physics 2019-03-26 Samuel P. Groth , Athanasios G. Polimeridis , Jacob K. White

Scattering of starlight by dust, molecules and electrons in spiral galaxies will produce a modification of the direct intensity and a polarization in the observed light. We treat the case where the distribution of scatterers can be…

Astrophysics · Physics 2009-10-31 J. F. L. Simmons , E. Audit

We study the emergence of collective scattering in the presence of dipole-dipole interactions when we illuminate a cold cloud of rubidium atoms with a near-resonant and weak intensity laser. The size of the atomic sample is comparable to…

We consider simple hydrodynamical models of galactic dark matter in which the galactic halo is a self-gravitating and self-interacting gas that dominates the dynamics of the galaxy. Modeling this halo as a sphericaly symmetric and static…

High Energy Physics - Phenomenology · Physics 2007-05-23 Luis G. Cabral-Rosetti , Dario Nunez , Roberto A. Sussman , Tonatiuh Matos

We show that the experimentally observed behavior of thermal conductivity of dielectric glasses over a wide temperature range can be explained by a combination of two scattering processes. The first one comes from the phonon scattering due…

Materials Science · Physics 2009-10-31 V. A. Osipov , S. E. Krasavin