QSO+Galaxy Association and Discrepant Redshifts in NEQ3

Spectroscopy and deep imaging of the group NEQ3 are presented. This system isformed by three compact objects with relative separations of ~2.6 and ~2.8arcsec, and a lenticular galaxy at ~17 arcsec from the geometric centre of thegroup. A diffuse filament is located on a line joining the three compactobjects and the main galaxy. Analysis of these observations confirms theredshift previously known for three of the objects (z=0.1239 for the maingalaxy, and z=0.1935 and 0.1939 for two of the compact objects). We have alsodetermined the previously unknown redshift of the third compact object asz=0.2229. Using the relative strength and width of the main spectral lines, wehave classified the compact objects as two HII galaxies and one QSO (the objectat z=0.1935). With cross-correlation techniques, we have tentatively estimatedthe redshift of the filament as z=0.19 (although a weaker component alsoappears at z=0.12) so that it is probably associated with the halo of the twocompact objects at this redshift. The two objects at redshift ~0.19 representpossibly one of the more clear examples of starburst (and perhaps QSO activity)driven by interaction. These, and the relation between these two objects andthe other two at (~0.12 and ~0.22) make the nature of this system intriguing,being difficult to explain the whole association on conventional scenarios.Comment: 15 pages, 3 figures, ApJ Letter accepte