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 Source Flux Density Comparison

The H and the radio continuum images of the MCs are found to be closely correlated, in the sense of an overall coincidence of peaks in the two surveys and a strong resemblance around giant star formation regions such as 30 Doradus. Here, we will concentrate on the discrete source flux density comparison between surveys from these two wavelengths.

The comparison between the source radio flux density at the 4.75 GHz survey (4.85 GHz survey for the SMC) and the H survey is shown in Figs. 1a and 1b. All classified HII regions and SNRs embedded in HII regions appear in both the radio and H surveys.

An overlap between HII regions and SNRs is noted and the reason for this is that most of the H bright SNRs are embedded in HII regions. The majority of background radio sources towards the MCs are not detected in the H surveys.

 
Figure 1: The comparison of H and radio flux density at 4.75 GHz (4.85 GHz for the SMC) for different classes of sources towards a) the LMC and b) the SMC. Asterisks represents SNRs; filled squares - HII Regions; open circles - background sources; and filled triangles - unclassified sources. The dotted line represents the approximate threshold of the radio survey. Sources below the dotted lines represent non-detections.

© Copyright Astronomical Society of Australia 1997