Loops and spurs: the angular power spectrum of the Galactic synchrotron background
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Loops and spurs : the angular power spectrum of the Galactic synchrotron background. / Mertsch, Philipp; Sarkar, Subir.
In: Journal of Cosmology and Astroparticle Physics, Vol. 2013, No. 6, 041, 01.06.2013.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Loops and spurs
T2 - the angular power spectrum of the Galactic synchrotron background
AU - Mertsch, Philipp
AU - Sarkar, Subir
PY - 2013/6/1
Y1 - 2013/6/1
N2 - We present a new model of the diffuse Galactic synchrotron radiation, concentratingon 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.
AB - We present a new model of the diffuse Galactic synchrotron radiation, concentratingon 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.
U2 - 10.1088/1475-7516/2013/06/041
DO - 10.1088/1475-7516/2013/06/041
M3 - Journal article
VL - 2013
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
SN - 1475-7516
IS - 6
M1 - 041
ER -
ID: 97171852