A Comparison of Discrete Sources in Radio and H surveys of the Magellanic Clouds - and the Potential for the New H Survey

Radio to H Comparison of the Sources towards the Large Magellanic Cloud

The comparison of the radio and H surveys resulted in the discovery of 180 sources common to both surveys. The basic criterion for positive source identification is that a source must lie within 2.5'á of its counterpart. Using the common area of the radio and H surveys and the search criterion we expect not more than six sources to have positional coincidence by chance alignment. The most accurate radio positions available are from the highest radio-frequency survey on which the source appears. These positions were compared with H positions listed in Kennicutt & Hodge (1986).

Positional comparisons were undertaken for all 180 sources common to the radio and H surveys of the LMC. The mean difference in RA is 17"5"á (radio-H) with a standard deviation (SD) of 52". The difference in Dec is 7"5"á (SD=50"). This uncertainty is consistent with the combined positional uncertainties for the radio (defined in Paperá IV) and the H sources, and retrospectively justifies the initial identification criteria of 2.5'á (which is equivalent to 2.8 in both RA and Dec).

á© Copyright Astronomical Society of Australia 1997