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

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


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 overdensities that may extend up to ∼10 physical Mpc. This scenario, however, has not been confirmed observationally, as the search for galaxy overdensities around high-z quasars has returned conflicting results. The field around the z = 6:31 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 (∼250 × 250) 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 catalogs in the Y-and J-band, and matched those with our photometric catalog in the r, z, and i bands presented in our previous paper and based on sources with zAB < 25:2 detected using z-band images from the the Large Binocular Cameras (LBC) at the Large Binocular Telescope (LBT) over the same field of view. We used these new infrared data together with H and K photometric measurements from the MUlti-wavelength Survey by Yale-Chile (MUSYC) and with the Spitzer Infrared Array Camera (IRAC) data to refine our selection of Lyman break galaxies (LBGs), extending our selection criteria to galaxies in the range 25:2 < zAB < 25:7. We selected 21 robust high redshift candidates in the J1030 field with photometric redshift z ∼ 6 and colors i-z = 1:3. We found a significant asymmetry in the distribution of the high redshift galaxies in J1030, supporting the existence of a coherent large-scale structure around the quasar. We estimated an overdensity of z ∼ 6 galaxies in the field of d = 2:4, which is significant at >4s. The overdensity value and its significance are higher than those found in our previous paper and we interpret this as evidence of an improved LBG selection.

Original languageEnglish (US)
Article numberA23
JournalAstronomy and Astrophysics
StatePublished - Oct 1 2017
Externally publishedYes


  • Galaxies: high-redshift
  • Galaxies: photometry

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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