The -Cygni Region of the Cygnus X Radio Source

Abstract

A high resolution survey of the γ -Cygni region of the Cygnus X radio source has been carried out at a wavelength of 4.6 cm using the 10 metre paraboloid at the Algonquin Radio Observatory. Comparison of these results with two other surveys of comparable resolution indicates that one, and possibly two, sources in the region radiate by a different mechanism than the Cygnus X sources in general. One is the strong source which has been termed the ‘ γ -Cygni source’, and the other is a weaker source situated 40′ to the north-west of this. These may be components of the same emission feature. Aside from these, twenty-nine other emission peaks have been identified in the surveyed region. Electron densities and masses of ionized gas have been derived for these on the assumption that the Cygnus X complex is at a distance of 1 500 parsecs. An average electron density of 25 cm −3 has been found for the resolved sources in this area of Cygnus X, and by comparison with optical observations a mean visual (H α ) absorption of 1.5 m was deduced for the western half of the surveyed area. The mass of ionized hydrogen in the whole Cygnus X complex is estimated to be 6 × 10 5 solar masses.