HST Spectroscopy of Four Luminous Compact Blue Galaxies at Intermediate z.1

We present a spectroscopic study of 4 blue (BV 0:6) compact (B 21:0 mag arcsec2) eld galaxies with redshifts 0:095 z 0:438 and absolute magnitudes MB between-17.5 and-21.1. The spectra, taken with the STIS spectrograph on board of the HST telescope, show prominent emission lines whose spatial proles reveal, at least in two cases, the existence of various star-forming regions and an underlying stellar population. The derived Star Formation Rates from H luminosities in these star forming regions range between 0.5 and 7 M yr 1. These are typically ten times more luminous than and approximately twice as large as the well known giant H II region 30-Doradus in the LMC. When compared to local star bursting galaxies, the objects presented here turn out to be very similar to the brightest H II galaxies in terms of the areal star formation rate and in the ratio between the galaxy half light diameter to the line-emitting region half light diameter (Deff=D0)