The object NGC 6908 was once thought to be simply a surface-brightness enhancement in the eastern spiral arm of the nearby spiral galaxy NGC 6907 .
Based on an examination of near-infrared imaging , the object is shown in fact to be a lenticular S0 ( 6/7 ) galaxy hidden in the optical glare of the disk and spiral structure of the larger galaxy .
New radial velocities of NGC 6908 ( 3,060 \pm 16 ( emission ) ; 3,113 \pm 73 km/s ( absorption ) ) have been obtained at the Baade 6.5m and the duPont 2.5m telescopes at Las Campanas , Chile placing NGC 6908 at the same expansion-velocity distance as NGC 6907 ( 3,190 \pm 5 km/s ) , eliminating the possibility of a purely chance line-of-sight coincidence .
The once-enigmatic asymmetries in the disk and outer spiral structure of NGC 6907 are now explained as being due to an advanced merger event .
Newly discovered tails and debris in the outer reaches of this galaxy further support the merger scenario for this system .
This pair of galaxies is a rather striking example of two objects discovered over 100 years ago , whose true nature was lost until modern detectors operating at infrared wavelengths gave us a new ( high-contrast ) look .
Other examples of embedded merger remnants may also reveal themselves in the growing samples of near-infrared imaging of nearby galaxies ; and a pilot study does reveal several other promising candidates for follow-up observations .