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Title: Diffuse sources, clustering, and the excess anisotropy of the radio synchrotron background
ABSTRACT

We present the largest low frequency (120 MHz) arcminute resolution image of the radio synchrotron background (RSB) to date, and its corresponding angular power spectrum of anisotropies (APS) with angular scales ranging from 3° to 0.3 arcmin. We show that the RSB around the north celestial pole has a significant excess anisotropy power at all scales over a model of unclustered point sources based on source counts of known source classes. This anisotropy excess, which does not seem attributable to the diffuse Galactic emission, could be linked to the surface brightness excess of the RSB. To better understand the information contained within the measured APS, we model the RSB varying the brightness distribution, size, and angular clustering of potential sources. We show that the observed APS could be produced by a population of faint clustered point sources only if the clustering is extreme and the size of the Gaussian clusters is ≲1 arcmin. We also show that the observed APS could be produced by a population of faint diffuse sources with sizes ≲1 arcmin, and this is supported by features present in our image. Both of these cases would also cause an associated surface brightness excess. These classes of sources are in a parameter space not well probed by even the deepest radio surveys to date.

 
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Award ID(s):
1908960 2209420 1914409
NSF-PAR ID:
10426637
Author(s) / Creator(s):
; ; ; ; ; ;
Publisher / Repository:
Oxford University Press
Date Published:
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
523
Issue:
4
ISSN:
0035-8711
Page Range / eLocation ID:
p. 5034-5046
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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