Characterizing the diffuse Galactic synchrotron emission at arcminute angular scales is needed to reliably remove foregrounds in cosmological 21-cm measurements .
The study of this emission is also interesting in its own right .
Here , we quantify the fluctuations of the diffuse Galactic synchrotron emission using visibility data for two of the fields observed by the TIFR GMRT Sky Survey ( TGSS ) .
We have used the 2D Tapered Gridded Estimator ( TGE ) to estimate the angular power spectrum ( C _ { \ell } ) from the visibilities .
We find that the sky signal , after subtracting the point sources , is likely dominated by the diffuse Galactic synchrotron radiation across the angular multipole range 240 \leq \ell \lesssim 500 .
We present a power law fit , C _ { \ell } = A \times \big ( \frac { 1000 } { l } \big ) ^ { \beta } , to the measured C _ { \ell } over this \ell range .
We find that ( A, \beta ) have values ( 356 \pm 109 \leavevmode \nobreak { mK ^ { 2 } } , 2.8 \pm 0.3 ) and ( 54 \pm 26 \leavevmode \nobreak { mK ^ { 2 } } , 2.2 \pm 0.4 ) in the two fields .
For the second field , however , there is indication of a significant residual point source contribution , and for this field we interpret the measured C _ { \ell } as an upper limit for the diffuse Galactic synchrotron emission .
While in both fields the slopes are consistent with earlier measurements , the second field appears to have an amplitude which is considerably smaller compared to similar measurements in other parts of the sky .