Spectroscopic confirmation of high-redshift supernovae with the ESO VLT

We present VLT FORS1 and FORS2 spectra of 39 candidate high-redshift supernovae that were discovered as part of a cosmological study using type Ia supernovae (SNe Ia) over a wide range of redshifts. From the spectra alone, 20 candidates are spectrally classified as SNe Ia with redshifts ranging from $z=0.212$ to $z=1.181$. Of the remaining 19 candidates, 1 might be a type II supernova and 11 exhibit broad supernova-like spectral features and/or have supernova-like light curves. The candidates were discovered in 8 separate ground-based searches. In those searches in which SNe Ia at $z \sim 0.5$ were targeted, over 80% of the observed candidates were spectrally classified as SNe Ia. In those searches in which SNe Ia with $z > 1$ were targeted, 4 candidates with $z > 1$ were spectrally classified as SNe Ia and later followed with ground and space based observatories. We present the spectra of all candidates, including those that could not be spectrally classified as supernova