The discovery of a massive supercluster at z= 0.9 in the UKIDSS Deep eXtragalactic Survey

Centre for Astrophysics, Science & Technology Research Institute, University of Hertfordshire, Hatfield, Herts AL10 9AB; Gemini Observatory, 670 North A'ohoku Place, Hilo, HI 96720, USA; Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ
Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.52). 07/2007; 379(4):1343 - 1351. DOI: 10.1111/j.1365-2966.2007.12037.x
Source: OAI

ABSTRACT We analyse the first publicly released deep field of the UK Infrared Deep Sky Survey (UKIDSS) Deep eXtragalactic Survey to identify candidate galaxy overdensities at z∼ 1 across ∼1 deg2 in the ELAIS-N1 field. Using I−K, J−K and K− 3.6 μm colours, we identify and spectroscopically follow up five candidate structures with Gemini/Gemini Multi-Object Spectrograph and confirm that they are all true overdensities with between five and 19 members each. Surprisingly, all five structures lie in a narrow redshift range at z= 0.89 ± 0.01, although they are spread across 30 Mpc on the sky. We also find a more distant overdensity at z= 1.09 in one of the spectroscopic survey regions. These five overdense regions lying in a narrow redshift range indicate the presence of a supercluster in this field and by comparing with mock cluster catalogues 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.

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