A peculiar stellar complex in NGC 6946 or the blue compact galaxy in front of this galaxy?

Efremov, Y. N., Alfaro, E., Hodge, P., Larsen, S., and Munoz-Tunon, C.
Astronomical and Astrophysical Transactions, vol. 23, Issue 2, p.95-101


The origin of the peculiar stellar complex in the outskirts of the spiral galaxy NGC 6946 is discussed. The complex hosts a superstar cluster, two dozen smaller bright clusters and many high-luminosity stars 5-30 Myears old. In spite of this, no features in H I or CO are associated with the complex. The most simple explanation is that the complex is a foreground blue compact galaxy, a member of the NGC 6946 group. The arc of high light absorption along the complex rim could then be the result of the ram pressure of the intergalactic medium gas. The existing velocity data cannot prove or disprove this hypothesis.