De Vaucouleurs Atlas Type: SAB(rs)c
Telescope: Perkins 1.8-m
North up , East left
Field Dimensions: 5.1 x 3.8 arcminutes
RC3 Type: SAB(rs)c
RSA Type: SBc(s)II.3
Surface Brightness Range Displayed: 18.5-26.0 mag per square arcsec
Absolute Blue Magnitude: -18.5
Elmegreen Spiral Arm Class: AC 5
De Vaucouleurs Atlas Description:
The dominant characteristic of NGC 1637 is a strong lopsidedness in spite of being relatively isolated. A weak, dusty bar is oriented roughly east-west. Breaking from the ends of this bar are two bright arms which form a fairly well-defined inner pseudoring . Outside this ring, the spiral structure is asymmetric, dominated by one major arm. The rest of the disk structure is mottled and somewhat flocculent in nature.
Block et al. (1999a) give a classification of E-beta/L-gamma (or H2-beta/H1-gamma) for NGC 1637 in the dust-penetrated scheme of Block and Puerari (1999). The H1-gamma part refers to the single outer arm.
Rix and Zaritsky (1995) have shown that 30% of field spiral galaxies in a magnitude-limited sample have significant m=1 Fourier components in their stellar light distributions. Zaritsky and Rix (1997) have suggested that these components are largely caused by tidal interactions and they estimate the merger rate of small companions.