De Vaucouleurs Atlas Type: (R')SAB(rl)a
Telescope: CTIO 0.9-m
North up , East left
Field Dimensions: 3.0 x 3.4 arcminutes
RC3 Type: SAB(r)a
RSA Type: Sa(s)
Surface Brightness Range Displayed: 17.5-26.5 mag per square arcsec
Absolute Blue Magnitude: -19.3
De Vaucouleurs Atlas Description:
NGC 1317 is a double-barred galaxy (Schweizer 1980) where the secondary bar is a more prominent feature than the primary bar . The two bars are oriented virtually exactly perpendicular to each other, which is unusual for double-barred systems where misalignment is often seen (Erwin 2004 and references therein). Friedli and Martinet (1993) discuss the possible reasons for the alignment in this case.
NGC 1317 is another example of a double nuclear ring-pseudoring morphology in an early-type barred galaxy. (The previously discussed example is NGC 4314 .) The nuclear region includes a secondary bar surrounded by a strong nuclear lens . These features lie well inside a boxy oval nuclear ring, aligned with the secondary bar , that is patchy and includes recent star formation. Breaking from the major axis of the nuclear ring are two spiral arms that form what is technically a nuclear pseudoring; these arms fade into strongly curved leading dust lanes that are part of the much larger primary bar . The primary bar is mainly a broad oval, hence the classification SAB. Surrounding the primary bar is a circular ring that technically should be classified as an inner ring because it is mostly filled by the primary bar . Buta (1995a) identified another ring feature further out that could be an outer ring . The H-alpha distribution in the nuclear ring region also shows a double nuclear ring-pseudoring morphology (Crocker, Baugus, and Buta 1996).