Abstract
Observations at 2.7 mm and at 1.5 cm were used to study the millimeter spectra and variability of 176 bright, compact radio sources. More than 20 percent of the flat-spectrum sources, but none of the steep-spectrum sources, were seen to vary at 1.5 cm by at least 30 percent over ten months. This is consistent with the hypothesis that flat-spectrum sources are compact and possibly beamed, while steep-spectrum sources are not. These data can also be used to choose sources for VLBI observations and for calibration of millimeter-wave observations.
#Table 1. Millimeter data for bright VLA calibrators (N=176 entries)
# 20 GHz 20 GHz 110 GHz
# July 1986 April 1987 April 1987
#Source RADEC_B1950 RADEC_J2000 S1.5cm/mJy S1.5cm/mJy S2.7mm/mJy V {alpha}_mm
#---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----
0003-066 000340.293-064017.30 000613.9-062335 976 7 1125 78 +0.08
0016+731 001654.198+731051.46 001945.7+732730 1540 6 1734 17 820 56 0.12 -0.44