Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmic-ray leptons, magnetic fields and interstellar synchrotron
  emission   Interstellar synchrotron emission depends on Galactic magnetic fields and on
cosmic-ray leptons. Observations of radio emission are an important tool for
studying cosmic-ray propagation models and interstellar electron spectrum and
distribution in the Galaxy. We present the latest developments in our modeling
of Galactic synchrotron emission with the GALPROP code, including polarization,
absorption, and free-free emission. Using surveys over a wide range of radio
frequencies and polarization measurements, we derive constraints on the
low-energy interstellar cosmic-ray electron spectrum, magnetic fields and
cosmic-ray propagation models. This work is of interest for studies of
interstellar gamma-ray emission with Fermi-LAT, and synchrotron for the Planck
mission.

20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th