Paper detail

Low frequency results for the radio galaxies and the role of GMRT

We have studied several radio galaxies at low radio frequencies using GMRT. Our prime motivation to detect faint radio emission at very low frequencies due to low energy electrons. Our results provide evidence that there exists two classes of sources on morphological grounds. The first class is explained by the simple picture of spectral electron ageing but in the second class the low-frequency synchrotron emission fades (nearly) as rapidly as high-frequency synchrotron emission. In addition, in several sources, the spectra of low-surface-brightness features are flatter than the spectra of high-surface-brightness features, which suggests that either the simple picture of spectral electron ageing needs revision or we need to re-examine the formation mechanism of such sources. The images and statistics, and the relevance of these results along with the role of GMRT in exploring several unknowns are presented.