A DRAMATIC MILLIMETER WAVELENGTH FLARE IN THE GAMMA-RAY BLAZAR NRAO-530

We present 3 mm wavelength VLBI observations and up to 30 yr of monito ring at radio through submillimeter wavelengths of the gamma-ray blaza r NRAO 530. We discuss the dramatic hare that tripled the millimeter w avelength flux in 1994 and 1995 following three decades of increasing activity. VLBI observations during the flare show the creation of new components in a bent jet on subparsec scales. The components move at a n apparent velocity of 7c. The observations also imply expansion in a separate component with a speed greater than 26c. We apply synchrotron self-Compton models to the core and jet to determine magnetic field s trengths, particle densities, and Doppler boosting factors. We are una ble to provide a satisfactory physical explanation for the high appare nt velocity component. The increase in millimeter and radio wavelength fluxes is correlated with a rise in the gamma-ray flux detected by EG RET. We show that gamma-ray detections do not always occur during or i mmediately prior to a millimeter wavelength hare, contrary to assertio ns in the literature. We associate the VLBI component creation with th e gamma-ray activity, although not with a specific hare. We consider w hat may distinguish gamma-ray blazars from other variable, hat-spectru m radio objects. Our data strengthen the correlation between superlumi nal motion and gamma-ray emission in blazars. The distribution of jet misalignment angle for 28 EGRET sources, determined from a survey of t he literature, does not differ significantly from that of other blazar s. This suggests that the geometries of gamma-ray blazars do not diffe r from those of gamma-ray-quiet blazars on the scales sampled by VLBI.