出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Deep surveys of the sky at low radio frequencies provide important inputs towards identifying AGN and starburst galaxies from both the structure and spectra of these sources. Such observations could also provide evidence of relic emission from earlier cycles of activity in an AGN, possibly caused by periodic ‘feeding’ of a supermassive black hole. In this paper we present deep radio observations at low radio frequencies of selected fields using the Giant Metrewave Radio Telescope (GMRT). We identify possible tailed radio sources in clusters of galaxies at moderate redshifts, summarise our results on the flattening of the source counts which we have seen for the first time at these wavelengths and which is likely to be due to a combination of both starburst galaxies and low-luminosity AGN. We present images of selected sources, some of which have very steep spectra, and discuss the nature of these objects.
