WNB 1851+5707. Top-left panel image has been taken at 1.4 GHz with the VLA in A+B+C configuration, the restoring beam FWHM is 3.7″ × 3.3″. The contours of the radio intensity are overlaid on the optical DSS2 image. WNB 1851+5707 is composed of two distinct dying sources labeled a and b. The top-right panel shows the overlay of the spectral index image between 1.4 and 4.8 GHz with the 4.8 GHz contour levels of the VLA C+D array image. The restoring beam FWHM is 5.3″ × 5.0″. The sensitivity levels of the 1.4 and 4.8 GHz images are 17 and 9   μJy/beam, respectively. Radio contours start from a level of 3σ-rms and scale by . In the bottom panel, we show the integrated spectrum of the source along with the best-fit synchrotron model. The radio spectrum is representative of WNB 1851+5707a, the brighter of the two dying sources (see text).