Loops and spurs: the angular power spectrum of the Galactic synchrotron background

Journal Article · Sat Jun 01 04:00:00 EDT 2013 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2013/06/041· OSTI ID:22282776

Mertsch, Philipp ^[1]; Sarkar, Subir ^[2]

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1. Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, M/S 29, Menlo Park, CA 94025 (United States)
2. Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

We present a new model of the diffuse Galactic synchrotron radiation, concentrating on its angular anisotropies. While previous studies have focussed on either the variation of the emissivity on large ( ∼ kpc) scales, or on fluctuations due to MHD turbulence in the interstellar medium, we unify these approaches to match the angular power spectrum. We note that the usual turbulence cascade calculation ignores spatial correlations at the injection scale ( ∼ 100 pc) due to compression of the interstellar medium by of O(1000) old supernova remnants — the 'radio loops' only four of which are visible in radio maps. This new component naturally provides the otherwise missing power on intermediate and small scales in the all-sky map at 408 MHz. Our model can enable more reliable subtraction of the synchrotron foreground for studies of CMB anisotropies or searches for dark matter annihilation. We conclude with some remarks on the relevance to modelling of the polarised foreground.

• OSTI ID: 22282776
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 06 Vol. 2013; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
ANNIHILATION
ASTROPHYSICS
CORRELATIONS
COSMOLOGY
EMISSIVITY
ENERGY SPECTRA
MAGNETOHYDRODYNAMICS
MHZ RANGE
MILKY WAY
NONLUMINOUS MATTER
RELICT RADIATION
SUPERNOVA REMNANTS
SYNCHROTRON RADIATION
TURBULENCE