C.D.S. - SIMBAD4 rel 1.7 - 2021.03.07CET04:45:09

2009A&A...508.1099J - Astronomy and Astrophysics, volume 508, 1099-1116 (2009/12-4)

Positron transport in the interstellar medium.


Abstract (from CDS):

We seek to understand the propagation mechanisms of positrons in the interstellar medium (ISM). This understanding is a key to determine whether the spatial distribution of the annihilation emission observed in our Galaxy reflects the spatial distribution of positron sources and, therefore, makes it possible to place constraints on the origin of positrons. We review the different processes that are likely to affect the transport of positrons in the ISM. These processes fall into three broad categories: scattering off magnetohydrodynamic waves, collisions with particles of the interstellar gas, and advection with large-scale fluid motions. We assess the efficiency of each process and describe its impact on the propagation of positrons. We also develop a model of positron propagation, based on Monte-Carlo simulations, which enable us to estimate the distances traveled by positrons in the different phases of the ISM. We find that low-energy (≲10MeV) positrons generally have negligible interactions with magnetohydrodynamic waves, insofar as these waves are heavily damped. Positron propagation is mainly controlled by collisions with gas particles. Under these circumstances, positrons can travel very large distances (up to ∼30kpc/nH/cm3 for 1MeV positrons) along magnetic field lines before annihilating.

Abstract Copyright:

Journal keyword(s): gamma rays: theory - diffusion - plasmas

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 GAL 000.0+00.0 gam 17 45 39.60213 -29 00 22.0000           ~ 12014 0
2 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 3601 3
3 NAME Galactic Bulge reg ~ ~           ~ 3535 0

    Equat.    Gal    SGal    Ecl

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