A2626 and Friends: Large- and Small-scale Structure

Abstract

New MMT/Hectospec spectroscopy centered on the galaxy cluster A2626 and covering a similar to 1.8 deg(2) area out to z similar to 0.46 more than doubles the number of galaxy redshifts in this region. The spectra confirm four clusters previously identified photometrically. A2625, which was previously thought to be a close neighbor of A2626, is in fact much more distant. The new data show six substructures associated with A2626 and five more associated with A2637. There is also a highly collimated collection of galaxies and galaxy groups between A2626 and A2637 having at least three and probably four substructures. At larger scales, the A2626-A2637 complex is not connected to the Pegasus-Perseus filament.