Search and study of ultracompact HII regions

Abstract: We present results from a sample of 106 high-luminosity IRAS sources observed with the Very Large Array in the B and C configurations. 96 sources were observed in the X-band and 52 in the K-band, with 42 of them observed at both wavelengths. We also used previously published observations in the C-band for 14 of them. The detection rate of sources with 3.6~cm continuum emission was $\sim25\%$, while only 10\% have emission at 1.3~cm. In order to investigate the nature of these sources, their physical parameters were calculated mainly using the 3.6~cm continuum emission, and for sources detected at two wavelengths, we used the best fit of three HII region models with different geometries. As a final result, we present a catalog of the detected sources, which includes their basic physical parameters for further analysis. The catalog contains 17 ultracompact HII regions and 3 compact HII regions.