http://arxiv.org/abs/1609.01308
We extract the radio spectral index, $\alpha$, from the 541,195 common sources observed in 150 MHz TIFR GMRT Sky Survey (TGSS) and 1.4 GHz NRAO VLA Sky Survey (NVSS). These catalogs cover about $80\%$ of the sky and represent the largest radio population. We confirm the steepening of $\alpha$ with increasing flux density. Further, we observe an increase in $\alpha$ with source size (TGSS measured) saturating araound size 50 arcsec to $0.83\pm0.01$. From this saturated value, we constrain the electron energy injection spectral index, $\gamma$, and the fractional contribution of supernova remnants to the total radio flux. Our results indicate relatively low $\gamma \sim 1.8-1.9$ and a large supernova remnants contribution ($\sim 15-25\%$). For very compact sources the convection and the thermal radio emission are likely to be important.
P. Tiwari and A. Nusser
Wed, 7 Sep 16
56/61
Comments: 12 pages, 7 figures
You must be logged in to post a comment.