FIRST-based survey of compact Steep Spectrum sources. I. MERLIN images of arc-second scale objects

Compact Steep Spectrum (CSS) sources are powerful extragalactic radio sources with angular dimensions of the order of a few arcseconds or less. Such a compactness is apparently linked to the youth of these objects. The majority of CSSs investigated so far have been known since the early 1980s. This paper is the first in a series where we report the results of an observational campaign targeted on a completely new sample of CSSs which are significantly weaker than those investigated before. The ultimate goal of that campaign is to find out how "weak" CSSs compare to "strong", classical ones, especially with regard to the morphologies. Here we present an analysis of morphological and physical properties of five relatively large sources based on MERLIN observations at 1.6 and 5 GHz.