... M81 and Arp s Loop . ... This deep image of the region reveals details in the bright yellow core, but at the same time follows fainter features along the galaxy's gorgeous blue spiral arms and sweeping dust lanes. ... Studied in the 1960s, Arp's loop has been thought to be a tidal tail , material pulled out of M81 by gravitational interaction with its large neighboring galaxy M82 . ... Publications with keywords: M 81 - loops - deep field . Publications with words: M 81 - loops - deep field . ...