Very high-resolution observations of the radio sources NRAO 150, OJ 287, 3C 273, M87, 1633 + 38, BL Lacertae, and 3C 454.3

Abstract

Very long baseline interferometer observations made at a wavelength of 2 and 2.8 cm with baselines ranging from 54 to 291 million wavelengths show a number of radio sources with only slightly resolved components, even on the longest baselines; the quasars 1633 + 38 and 3C 454.3, the objects 0J 287 and BL Lac, and the nucleus of M87 (Virgo A, 3C 274) all contain components <% 0.4 milli-arcsec. The smallest component we have observed is in the core of 3C 454.3, which contains about 50% of the total flux density and is < 0.2 milli-arcsec in diameter. The compact component in the nucleus of M87 is <% 1.5 light-months across, and contains about one-third of the total flux density of the nucleus at 2.8 cm. NRA0 150 and BL Lac are double: the components of NRA0 150 are separated by 0.6 milliarcsec, while BL Lac has an elongated structure consisting of a large (1.4 milli-arcsec) component separated by 1.25 milli-arcsec from a smaller (0.5 milli-arcsec) variable one. The present data on 3C 273 are consistent with triple models similar to those we discussed previously, but with a somewhat greater apparent separation of components. Subject headings: BL Lacertae objects - galaxies: nuclei - interferometry - quasars - radio sources: general