'Sunflower' galaxy (IMAGE) Case Western Reserve University Caption The best example is represented by the Sunflower galaxy (NGC 5055) with the strongest external field among SPARC galaxies, whose well-measured rotation curve shows a mildly declining behavior at large radial distance and can be accurately modeled only with an external field effect. Credit Creative Commons Usage Restrictions Credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.