Radio Maps of the Regions RCW 57 and W 49

Abstract

We present maps of the regions RCW57 and W59 in the frequency of 22 GHz with 4.’6 angular resolution. The thermal radio sources RCW57 II are well resolved in the map. RCW57 I presents, at this frequency a diameter twice as large as that reported at 5 GHz, obtained with similar resolution, but coincides with the size of the source at the wavelenght of 1 mm. In the map of the RCW57 region we detected also the supernova remnant G291.0-0.1, of plerionic type. We find a break in the spectrum of this source between 8 and 22 GHz, with the spectral index changing from −0.29 to −0.77. This behaviour is also found in other remnats of the same type.