The Intrinsic Size of Sagittarius A* from 0.35 to 6 cm

Abstract

We present new high-resolution observations of Sagittarius A* at wavelengths of 17.4-23.8 cm with the Very Large Array in the A configuration with the Pie Town Very Long Baseline Array (VLBA) antenna. We use the measured sizes to calibrate the interstellar scattering law and find that the major axis size of the scattering law is smaller by ~6% than previous estimates. Using the new scattering law, we are able to determine the intrinsic size of Sgr A* at wavelengths from 0.35 to 6 cm using existing results from the VLBA. The new law increases the intrinsic size by ~20% at 0.7 cm and <5% at 0.35 cm. The intrinsic size is 13<SUP>+7</SUP><SUB>-3</SUB>R<SUB>S</SUB> at 0.35 cm and is proportional to lambda<SUP>gamma</SUP>, where gamma is in the range 1.3-1.7.