Eyes on the Milliarcsecond Universe: the Very Long Baseline Array

The Very Long Baseline Array (VLBA) is an array of ten identical 25-meter antennas centered in New Mexico and spread from Hawaii to the Virgin Islands. The data from these antennas are usually recorded on disks and sent to the VLBA control center located in Socorro New Mexico for correlation. When the telescopes are correlated the resulting data have angular resolution of 0.1-20 milliarcseconds, depending on observing frequency. Therefore the VLBA is an excellent tool to examine milliarcsecond scale structures in astronomical sources. The VLBA is sensitive to a wide range of phenomenon from Active Galactive Nuclei, Supernovae, Masers, Pulsars, X-ray Binaries to Brown Dwarves. The VLBA can also measure very precise astrometry and has been used, for example, to determine the structure of the spiral arms of the Galaxy. Since the VLBA is a dedicated array it can observe time variable phenomenon, which is especially crucial for time domain and multi-messenger astronomy.