A VLA Study of Ooty Small Diameter Sources

Extract

In the Ooty lunar occultation survey of about 711 sources at 327 MHz over 200 sources were classified as unresolved with upper limits of about 4″ (Kapahi(1986)). In order to study the nature of these sources I have observed a sub-sample of 71 sources with the VLA in the A-Configuration at 6 cm. The angular resolution ranged from 0.4 to 0.8 arc second. My observations show that of the above 71 sources 56% are well resolved doubles and triples resembling FRII sources with angular separations of 0″.4 to 8″. The flux density ratios of well separated doubles and triples range from 1 to about 8. However the LAS of sources with ratios of less than 2 is found to increase with decreasing flux density. Since most of the low flux density sources are in blank fields in the PSS prints no redshift information is available at present. Being FRII sources they are likely to be very distant sources at comologically interesting ranges of redshift. In order to test whether the above observed increase in the angular size is of cosmological significance we need optical identification and redshift information. These are being planned.