The angular power spectrum measurement of the Galactic synchrotron emission using the TGSS survey

Abstract

Characterizing the diffuse Galactic synchrotron emission (DGSE) at arcminute angular scales is needed to remove this foregrounds in cosmological 21-cm measurements. Here, we present the angular power spectrum (C ) measurement of the diffuse Galactic synchrotron emission using two fields observed by the TIFR GMRT Sky Survey (TGSS). We apply 2D Tapered Gridded Estimator (TGE) to estimate the C from the visibilities. We find that the residual data after subtracting the point sources is likely dominated by the diffuse Galactic synchrotron radiation across the angular multipole range 240 500. We fit a power law to the measured C over this range. We find that the slopes in both fields are consistent with earlier measurements. For the second field, however, we interpret the measured C as an upper limit for the DGSE as there is an indication of a significant residual point source contribution.