2013MNRAS.431L..58A

We present first results from electronic Multi-Element Remotely Linked Interferometer Network and electronic European VLBI Network observations of a small sample of ultrasteep spectrum radio sources, defined as those sources with a spectral index α < -1.4 between 74 and 325 MHz, which are unresolved on arcsecond scales. Such sources are currently poorly understood and a number of theories as to their origin have been proposed in the literature. The new observations described here have resulted in the first detection of two of these sources at milliarcsecond scales and show that a significant fraction of ultrasteep spectrum sources may have compact structures which can only be studied at the high resolution available with very long baseline interferometry (VLBI).