| Description | Based on Arp's category description, it's clear that Arp felt IC 5738 consists of two galaxies: an elliptical galaxy (left/lower) perturbing a spiral galaxy (right/upper). It seems likely that when initially observed as an entry in the IC, the spiral component of the pair was not resolved. Otherwise you might expect this object to have two IC entries. Even with the benefit of CMOS cameras and stacking, distinguishing the elliptical and spiral component is challenging. Note, I felt it easier to compare my image to Arp's by inverting the Palomar plate to a positive image. On my image, there are clearly two bulges consistent with two galaxies. While spiral arm-structure is not evident, the bright galactic core provides distinctive visual evidence of a barred spiral. Arp's image, printed, benefits from the resolution supported by a 200" aperture does definitively show spiral arm structure as well as a barred center. Of course, it seems highly likely that we're observing a merger in mid-process, though Arp never uses that word and remarks are silent on this observation. |
