The J1030 field


[A full description of the project, available data, results, people involved, and publications, can be found at the project website]

The mere existence of supermassive black holes (SMBHs) powering quasars in the first billion years of the Universe is a challenge for extragalactic astronomy since two decades. Theory argues that these objects must have formed and grown within large dark matter halos in dense environments, where early fueling and black hole accretion are easier. Such dense environments are expected to be traced by galaxy over-densities.

The field around the z=6.31 quasar SDSS J1030+0524 arguably features the best evidence of a large scale structure (LSS) around a supermassive black hole that formed more than 12 billion years ago. The existing superb multi-wavelength coverage of the field revealed a galaxy over-density at the quasar redshift that extends for a few physical Mpc across the sky.  This finding lends support to the idea that the most distant and massive black holes indeed form and grow within massive (> 1012 M) dark matter halos in large scale structures.

Remarkably, a second extra-ordinary large scale structure was serendipitously discovered in the J1030 field, that is a galaxy overdensity (protocluster) around a powerful FRII radio-galaxy at z=1.7 whose energy output is promoting star formation in four protocluster members simultaneously. This is a rare example of “positive AGN feedback” on large scales, where the black hole is affecting the star formation of multiple galaxies at distances of few hundreds kpc. Recently, we discovered in this protocluster significant reservoirs of cold molecular gas that are fueling star formation in several of its members, including the FRII host, which appears as the likely progenitor of the Brightest Cluster Galaxy.

The J1030 field is then a unique laboratory to investigate the growth of distant supermassive black holes within large scale structures that are still assembling. On the one hand, it gives us the opportunity to understand whether BH fueling is really facilitated by the presence of large gas reservoirs in the  deep potential wells of large dark matter halos and/or by the frequent mergers of gas-rich galaxies in these dense environments. On the other hand, we can study what are the effects of the energy released by the BH during its active phases on the large scale structure around it, e.g. on the thermodynamics of the Intra Cluster Gas,  and/or on galaxy formation in the structure.

We are collecting data at all frequencies from premiere ground-based and space-based observatories. These include large observational programs with the Chandra X-ray satellite and the JVLA radio-telescope. Recently, we obtained data at  mm, optical, and radio frequencies using ALMA, VLT/LBT and LOFAR, respectively, that are currently under investigation. The abundance and quality of the data collected in the J1030 field make it one of the deepest and most complete multi-band surveys currently available over the entire sky.

Involved OAS Staff: Francesco Calura, Andrea Comastri, Roberto Decarli, Roberto Gilli, Giorgio LanzuisiMarco Mignoli, Eros Vanzella