NGC 613
NGC 613 is a barred spiral galaxy located 67 million light years away in the southern constellation of Sculptor. The galaxy was discovered by German-English astronomer William Herschel on 9 December 1798, then re-discovered and catalogued by Scottish astronomer James Dunlop on 5 August 1826. It was first photographed in 1912, which revealed the spiral form of the nebula. During the twentieth century, radio telescope observations showed that a linear feature in the nucleus was a relatively strong source of radio emission.
NGC 613 is inclined by an angle of 37° to the line of sight from the Earth along a position angle of 125°. The morphological classification of NGC 613 is SBbc, indicating that it is a spiral galaxy with a bar across the nucleus, a weak inner ring structure circling the bar, and moderate to loosely wound spiral arms. The bar is relatively broad but irregular in profile with a position angle that varies from 115–124° and dust lanes located along the leading edges. Star formation is occurring at the ends of the bar and extending along the well-defined spiral arms. The central bulge is readily apparent, with a radius of 14″.
The classification of the nucleus is of type HII, indicating a match to the spectrum of an H II region. Near the core, the stars have a velocity dispersion of 136 ± 20 km/s. The nucleus is a source of radio emission with the form of an inner ring with a radius of about and a linear feature that is perhaps perpendicular to it. The latter consists of three discrete blobs spanning approximately. Observations suggest the presence of a supermassive black hole at the core with a mass in the range times the mass of the Sun.