We present 90Â cm VLA imaging of the COSMOS field , comprising a circular area of 3.14 square degrees at 8.0 ^ { \prime \prime } \times 6.0 ^ { \prime \prime } angular resolution with an average rms of 0.5Â mJy/beam .
The extracted catalog contains 182 sources ( down to 5.5 \sigma ) , 30 of which are multi-component sources .
Using Monte Carlo artificial source simulations we derive the completeness of the catalog , and we show that our 90Â cm source counts agree very well with those from previous studies .
Using X-ray , NUV-NIR and radio COSMOS data to investigate the population mix of our 90Â cm radio sample , we find that our sample is dominated by active galactic nuclei ( AGN ) .
The average 90-20Â cm spectral index ( S _ { \nu } \propto \nu ^ { \alpha } , where S _ { \nu } is the flux density at frequency \nu , and \alpha the spectral index ) of our 90Â cm selected sources is -0.70 , with an interquartile range of -0.90 to -0.53 .
Only a few ultra-steep-spectrum sources are present in our sample , consistent with results in the literature for similar fields .
Our data do not show clear steepening of the spectral index with redshift .
Nevertheless , our sample suggests that sources with spectral indices steeper than -1 all lie at z \gtrsim 1 , in agreement with the idea that ultra-steep-spectrum radio sources may trace intermediate-redshift galaxies ( z \gtrsim 1 ) .