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arXiv · 1309.6645

A large-scale galaxy structure at z = 2.02 associated with the radio galaxy MRC0156-252

Audrey Galametz·Daniel Stern·Laura Pentericci·Carlos De Breuck·Joel Vernet·Dominika Wylezalek·Rene Fassbender·Nina Hatch·Jaron Kurk·Roderik Overzier·Alessandro Rettura·Nick Seymour
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Abstract

We present the spectroscopic confirmation of a structure of galaxies surrounding the radio galaxy MRC0156-252 at z = 2.02. The structure was initially discovered as an overdensity of both near-infrared selected z > 1.6 and mid-infrared selected z > 1.2 galaxy candidates. We used the VLT/FORS2 multi-object spectrograph to target ~80 high-redshift galaxy candidates, and obtain robust spectroscopic redshifts for more than half the targets. The majority of the confirmed sources are star-forming galaxies at z > 1.5. In addition to the radio galaxy, two of its close-by companions (< 6'') also show AGN signatures. Ten sources, including the radio galaxy, lie within |z - 2.020 | < 0.015 (i.e., velocity offsets < 1500 km/s) and within projected 2 Mpc comoving of the radio galaxy. Additional evidence suggests not only that the galaxy structure associated with MRC0156-252 is a forming galaxy cluster but also that this structure is most probably embedded in a larger scale structure.

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Audrey Galametz, Daniel Stern, Laura Pentericci, Carlos De Breuck, Joel Vernet, Dominika Wylezalek, Rene Fassbender, Nina Hatch, Jaron Kurk, Roderik Overzier, Alessandro Rettura, Nick Seymour. 2013-09-25. A large-scale galaxy structure at z = 2.02 associated with the radio galaxy MRC0156-252. https://doi.org/10.1051/0004-6361%2F201322345

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