2mm Wavelength VLBI of SiO Masers and AGN

Abstract

In April 2002 an array of antennas operating at 129GHz successfully detected VLBI fringes on both continuum AGN and SiO maser sources. The 129GHz fringes on maser sources represent the highest frequency spectral line VLBI detections to date. The AGN 3C279 was detected on long baselines at both 129GHz (and at 147GHz, see Krichbaum et al in these proceedings) yielding fringe spacings of 50-56 micro arc seconds, an angular resolution record. The array consisted of the University of Arizona Kittpeak 12m antenna, the Heinrich Hertz 10m Telescope (HHT), and the IRAM 30m dish on Pico Veleta. At 129GHz, a number of evolved stars and several young stellar objects exhibit strong SiO maser emission in the v=1 J=3-2 transition. Preliminary cross power spectra of SiO masers around the red hypergiant VYCMa on the HHT-KittPeak baseline ~190km are consistent with multiple spatially separate maser spots associated with the star. Future observations will include continuum observations of the radio source at the Galactic Center, SgrA*, and higher frequency maser lines including HCN and methanol.