De Vaucouleurs Atlas Type: (RR)SAB(rs)a
Telescope: WIYN 3.5-m
North up , East left
Field Dimensions: 6.7 x 5.0 arcminutes
RC3 Type: SB(r)a:
RSA Type: ------
Surface Brightness Range Displayed: 16.0-25.5 mag per square arcsec
Absolute Blue Magnitude: -20.3
De Vaucouleurs Atlas Description:
We illustrate this well-known Seyfert 2 galaxy with a very deep r-band image, as opposed to B. The galaxy has several remarkable features. First, it has two well-separated and well-defined outer rings, the only known example of such a phenomenon. Most double outer-ringed galaxies have features in the R1R2' ring-pseudoring combination (book Section 2.5). The inner outer ring in NGC 2273 is best-defined and is enhanced in two opposing quadrants, but is weak on its major axis. The outer outer ring is slightly fainter on one side of its major axis. Both features are fully closed and both merit an (R) classification, which we designate as "(RR)".
In the inner regions are more remarkable features. The inner pseudoring is of the wrapped arms type and is very well-defined. The arms making the ring appear to break from the ends of a weak bar, which appears to be mostly a foreshortened oval. This accounts for the SAB classification. There is a complex dust distribution in this broad oval, but most interesting is the small central spiral (see closeup r-band image). This feature is elongated approximately perpendicular to the main oval and at first site looks like it includes two strong spiral arms opening in the opposite sense to those defining the inner pseudoring . However, the HST image shows these arcs are simply the brighter parts of a dusty nuclear ring (see also Erwin 2004). In the B-RJ (where RJ=Johnson R) color index map, the inner arcs are the main sites of central star formation. Weak dust lanes in the oval curve outward from the nuclear ring, and then curve more to follow the inside of the inner pseudoring . Parts of the inner pseudoring are blue, as are parts of each outer ring . The core is red and small for an Sa galaxy, but is not unusual for a multi-ringed system.