De Vaucouleurs Atlas Type: (R)SA(rs)b
Telescope: CTIO 1.5-m
North down , East left
Field Dimensions: 13.0 x 9.7 arcminutes
RC3 Type: (R)SA(rs)b
RSA Type: Sb(rs)II
Surface Brightness Range Displayed: 16.0-26.0 mag per square arcsec
Absolute Blue Magnitude: -21.3
Elmegreen Spiral Arm Class: AC 3
De Vaucouleurs Atlas Description:
The structure of this very well-studied Seyfert 2 galaxy is remarkably regular. Although most research has centered on the activity in the nucleus, the rest of the galaxy is morphologically interesting. Most conspicuous in the atlas image is the bright outer ring , one of the largest and best in the sky. The ring connects to the inner zone along its minor axis, but is sufficiently closed to merit the (R) classification. The bright central zone is dominated by lightly flocculent spiral structure, with at least two clear arms. If deprojected, this spiral zone would be an oval similar to that seen in NGC 4736 . The similarity doesn't end there, however. In the center of the spiral zone, a small central pseudoring is seen. The feature is well-defined and oval in shape. Although not visible at all in blue light, a near-infrared bar crosses this small pseudoring (Thronson et al. 1989).
Although classified here as an inner pseudoring , the small central ring is more an analog of the nuclear rings of barred spirals . The Sb classification is based on the appearance of the spiral dominated zone, the general patchiness of the disk, and the small bulge. The Seyfert nucleus is visible inside the inner pseudoring .