The discovery of a massive supercluster at z=0.9 in the UKIDSS DXS

Swinbank, A. M.; Edge, A.; Smail, I.; Stott, J.; Bremer, M.; Sato, Y.; van Breukelen, C.; Jarvis, M.; Waddington, I.; Clewley, L.; Bergeron, J.; Cotter, G.; Dye, S.; Geach, J.; Gonzalez-Solares, E.; Hirst, P.; Ivison, R.; Rawlings, S.; Simpson, C.; Smith, G. P.; Verma, A.; Yamada, T.

The discovery of a massive supercluster at z=0.9 in the UKIDSS DXS

Authors

Description

We analyse the first publicly released deep field of the UKIDSS Deep eXtragalactic Survey (DXS) to identify candidate galaxy over-densities at z~1 across ~1 sq. degree in the ELAIS-N1 field. Using I-K, J-K and K-3.6um colours we identify and spectroscopically follow-up five candidate structures with Gemini/GMOS and confirm they are all true over-densities with between five and nineteen members each. Surprisingly, all five structures lie in a narrow redshift range at z=0.89+/-0.01, although they are spread across 30Mpc on the sky. We also find a more distant over-density at z=1.09 in one of the spectroscopic survey regions. These five over-dense regions lying in a narrow redshift range indicate the presence of a supercluster in this field and by comparing with mock cluster catalogs from N-body simulations we discuss the likely properties of this structure. Overall, we show that the properties of this supercluster are similar to the well-studied Shapley and Hercules superclusters at lower redshift.
In press at MNRAS, 11 pages, 5 figures