NGC 2665 (R$^{\prime}$)SAB(rs)ab
CTIO 1.5-m
R. Buta, D. A. Crocker
B-band, 600s, 0.54 arcsec/pix
18.0-28.0
bar torque class: x
SGC: (R)SB(rs)a
CSRG: (R $_1^{\prime}$)SB(r)a

Description - This galaxy contains an exceptionally strong example of an outer pseudoring that is complete and closes well. The inner regions include an oval zone with spiral structure and a bar which does not stand out well. The inner pseudoring is also a low contrast feature. NGC 2665 is an example of an early-type barred spiral which clearly has only a small bulge, more consistent with an Sc galaxy than an Sab. This inconsistency of Hubble type criteria is well-documented in the Hubble Atlas (Sandage 1961) and appears elsewhere in the present atlas.

Multi-Wavelength Morphology - The B-V color index map shows that the inner oval zone includes star formation and strong dust. Particularly noteworthy are two large blue star-forming complexes just off each end of the bar. The inner pseudoring has little contrast in this map. The color map also shows that the bright nucleus in the galaxy is blue. It appears to include a very small, barely resolved nuclear ring.

Interpretation - The shape of the outer ring neatly fits into the R $_1^{\prime}$ OLR subclass of outer pseudorings. This subclass is dominated by periodic orbits lying near and inside the outer Lindblad resonance. The corotation circle likely passes through the gap between the inner and outer pseudorings and near the locations of the two bright star-forming complexes near the bar ends. NGC 2665 is very similar to NGC 1433 but has only a low contrast bar and inner pseudoring and no secondary spiral arcs.

NGC 2665 B-V color index map of NGC 2665