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arXiv · 1706.02317

The primordial environment of supermassive black holes (II): deep Y and J band images around the z=6.3 quasar SDSS J1030+0524

B. Balmaverde·R. Gilli·M. Mignoli·M. Bolzonella·M. Brusa·N. Cappelluti·A. Comastri·E. Sani·E. Vanzella·C. Vignali·F. Vito·G. Zamorani
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Abstract

Many cosmological studies predict that early supermassive black holes (SMBHs) can only form in the most massive dark matter halos embedded within large scale structures marked by galaxy over-densities that may extend up to 10 physical Mpc. This scenario, however, has not been confirmed observationally, as the search for galaxy over-densities around high-z quasars has returned conflicting results. The field around the z=6.28 quasar SDSSJ1030+0524 (J1030) is unique for multi-band coverage and represents an excellent data legacy for studying the environment around a primordial SMBH. In this paper we present wide-area (25x25 arcmin), Y- and J-band imaging of the J1030 field obtained with the near infrared camera WIRCam at the Canada-France-Hawaii Telescope (CFHT). We built source catalogues in the Y- and J-band, and matched those with our photometric catalogue in the r, z, i bands presented in Morselli et al. (2014). We used these new infrared data together with H and K and Spitzer/IRAC data to refine our selection of Lyman Break Galaxies (LBGs), extending our selection criteria to galaxies in the range 25.2 =1.3. We found a significant asymmetry in the distribution of the high-z galaxies in J1030, supporting the existence of a coherent large-scale structure around the quasar. We compared our results with those of Bowler et al. (2015), who adopted similar LBGs selection criteria, and estimated an over-density of galaxies in the field of delta = 2.4, which is significant at >4 sigma. The over-density value and its significance are higher than those found in Morselli et al. (2014), and we interpret this as evidence of an improved LBG selection.

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B. Balmaverde, R. Gilli, M. Mignoli, M. Bolzonella, M. Brusa, N. Cappelluti, A. Comastri, E. Sani, E. Vanzella, C. Vignali, F. Vito, G. Zamorani. 2017-06-07. The primordial environment of supermassive black holes (II): deep Y and J band images around the z=6.3 quasar SDSS J1030+0524. https://doi.org/10.1051/0004-6361%2F201730683

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