%0 Generic %1 morselli2014primordial %A Morselli, L. %A Mignoli, M. %A Gilli, R. %A Vignali, C. %A Comastri, A. %A Sani, E. %A Cappelluti, N. %A Zamorani, G. %A Brusa, M. %A Gallozzi, S. %A Vanzella, E. %D 2014 %K environment high-z quasar %T The primordial environment of super massive black holes: large scale galaxy overdensities around $z\sim6$ QSOs with LBT %U http://arxiv.org/abs/1406.3961 %X We investigated the presence of galaxy overdensities around four $z\sim6$ QSOs, namely SDSS J1030+0524 (z = 6.28), SDSS J1148+5251 (z = 6.41), SDSS J1048+4637 (z = 6.20) and SDSS J1411+1217 (z = 5.95), through deep $r$-, $i$- and $z$- band imaging obtained with the wide-field ($\sim23'\times25'$) Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT). We adopted color-color selections within the $i-z$ vs $r-z$ plane to identify samples of $i$-band dropouts at the QSO redshift and measure their relative abundance and spatial distribution in the four LBC fields, each covering $\sim8\times8$ physical Mpc at $z\sim6$. The same selection criteria were then applied to $z$-band selected sources in the $\sim$1 deg$^2$ Subaru-XMM Newton Deep Survey to derive the expected number of dropouts over a blank LBC-sized field ($\sim$0.14 deg$^2$). The four observed QSO fields host a number of candidates larger than what is expected in a blank field. By defining as $i$-band dropouts objects with $z_AB<25$, $i-z>1.4$ and undetected in the $r$-band, we found 16, 10, 9, 12 dropouts in SDSS J1030+0524, SDSS J1148+5251, SDSS J1048+4637, and SDSS J1411+1217, respectively, whereas only 4.3 such objects are expected over a 0.14 deg$^2$ blank field. This corresponds to overdensity significances of 3.3, 1.9, 1.7, 2.5$\sigma$, respectively. By considering the total number of dropouts in the four LBC fields and comparing it with what is expected in four blank fields of 0.14 deg$^2$ each, we find that high-z QSOs reside in overdense environments at the $3.7\sigma$ level. This is the first direct and unambiguous measurement of the large scale structures around $z\sim6$ QSOs. shortened

@misc{morselli2014primordial, abstract = {We investigated the presence of galaxy overdensities around four $z\sim6$ QSOs, namely SDSS J1030+0524 (z = 6.28), SDSS J1148+5251 (z = 6.41), SDSS J1048+4637 (z = 6.20) and SDSS J1411+1217 (z = 5.95), through deep $r$-, $i$- and $z$- band imaging obtained with the wide-field ($\sim23'\times25'$) Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT). We adopted color-color selections within the $i-z$ vs $r-z$ plane to identify samples of $i$-band dropouts at the QSO redshift and measure their relative abundance and spatial distribution in the four LBC fields, each covering $\sim8\times8$ physical Mpc at $z\sim6$. The same selection criteria were then applied to $z$-band selected sources in the $\sim$1 deg$^2$ Subaru-XMM Newton Deep Survey to derive the expected number of dropouts over a blank LBC-sized field ($\sim$0.14 deg$^2$). The four observed QSO fields host a number of candidates larger than what is expected in a blank field. By defining as $i$-band dropouts objects with $z_{AB}<25$, $i-z>1.4$ and undetected in the $r$-band, we found 16, 10, 9, 12 dropouts in SDSS J1030+0524, SDSS J1148+5251, SDSS J1048+4637, and SDSS J1411+1217, respectively, whereas only 4.3 such objects are expected over a 0.14 deg$^2$ blank field. This corresponds to overdensity significances of 3.3, 1.9, 1.7, 2.5$\sigma$, respectively. By considering the total number of dropouts in the four LBC fields and comparing it with what is expected in four blank fields of 0.14 deg$^2$ each, we find that high-z QSOs reside in overdense environments at the $3.7\sigma$ level. This is the first direct and unambiguous measurement of the large scale structures around $z\sim6$ QSOs. [shortened]}, added-at = {2014-06-17T10:51:39.000+0200}, author = {Morselli, L. and Mignoli, M. and Gilli, R. and Vignali, C. and Comastri, A. and Sani, E. and Cappelluti, N. and Zamorani, G. and Brusa, M. and Gallozzi, S. and Vanzella, E.}, biburl = {https://www.bibsonomy.org/bibtex/2f261f629a52dc4c22723839ca09fa08a/miki}, description = {[1406.3961] The primordial environment of super massive black holes: large scale galaxy overdensities around $z\sim6$ QSOs with LBT}, interhash = {7c35c3f0a65d4bb3be0b370d75d9aa24}, intrahash = {f261f629a52dc4c22723839ca09fa08a}, keywords = {environment high-z quasar}, note = {cite arxiv:1406.3961Comment: 12 pages, 8 figures. Accepted for publication in A&A}, timestamp = {2014-06-17T10:51:39.000+0200}, title = {The primordial environment of super massive black holes: large scale galaxy overdensities around $z\sim6$ QSOs with LBT}, url = {http://arxiv.org/abs/1406.3961}, year = 2014 }