Multi-Wavelength Study of a Proto-BCG at z = 1.7
  In this work we performed a spectral energy distribution (SED) analysis in
the optical/infrared band of the host galaxy of a proto-brightest cluster
galaxy (BCG, NVSS J103023+052426) in a proto-cluster at z = 1.7. We found that
it features a vigorous star formation rate (SFR) of ${\sim}$570
$\mathrm{M_{\odot}}$/yr and a stellar mass of $M_{\ast} \sim 3.7 \times
10^{11}$ $\mathrm{M_{\odot}}$; the high corresponding specific SFR = $1.5 \pm
0.5$ $\mathrm{Gyr^{-1}}$ classifies this object as a starburst galaxy that will
deplete its molecular gas reservoir in $\sim$ $3.5 \times 10^8$ yr. Thus, this
system represents a rare example of a proto-BCG caught during the short phase
of its major stellar mass assembly. Moreover, we investigated the nature of the
host galaxy emission at 3.3 mm. We found that it originates from the cold dust
in the interstellar medium, even though a minor non-thermal AGN contribution
cannot be completely ruled out. Finally, we studied the polarized emission of
the lobes at 1.4 GHz. We unveiled a patchy structure where the polarization
fraction increases in the regions in which the total intensity shows a bending
morphology; in addition, the magnetic field orientation follows the direction
of the bendings. We interpret these features as possible indications of an
interaction with the intracluster medium. This strengthens the hypothesis of
positive AGN feedback, as inferred in previous studies of this object on the
basis of X-ray/mm/radio analysis. In this scenario, the proto-BCG heats the
surrounding medium and possibly enhances the SFR in nearby galaxies.
