Abell 1550. Top, left: total intensity radio contours of A1550 at 1.4 GHz with the VLA in D configuration. The image has a FWHM of 53′′  ×  53′′. The contour levels are drawn at −0.2, 0.2 mJy/beam, and the rest are spaced at intervals of a factor of . The sensitivity (1-σ) is 0.07 mJy/beam. Total intensity radio contours are overlaid on the Rosat PSPC X-ray image in the 0.1–2.4 keV band, taken from the RASS. The X-ray image has been convolved with a Gaussian of σ = 45′′. Top, right: total intensity radio contours and grayscale image at 1.4 GHz with the VLA in D configuration after subtraction of discrete sources. Bottom, left: total intensity radio contours of A1550 overlaid on the isodensity map of likely cluster members. Bottom, right: zoom of total intensity radio contours at the center of A1550 at 1.4 GHz with the VLA in C configuration. The image has a FWHM of 18′′  ×  18′′. The first contour level is drawn at 0.15 mJy/beam, and the rest are spaced at intervals of a factor of . The sensitivity (1σ) is 0.04 mJy/beam. The contours of the radio intensity are overlaid on the optical image taken from the SDSS (red plate).