SMBHs and Hot Gas in the MQN01 Protocluster- Extreme Conditions in a High-z Overdensity

The protocluster field MQN01 at z~3.25 provides a rare window into how extreme high-redshift environments influence the evolution of galaxies and their central supermassive black holes (SMBHs). This region, which hosts the largest Lya nebula in the Borisova et al. (2016) sample, features a dense network of filaments and one of the highest galaxy overdensities known at this epoch.I will present results from an ultra-deep (~650 ks) Chandra survey of MQN01, combined with MUSE and ALMA data. We identify an exceptional overdensity of X-ray AGN (~1000), surpassing those in protoclusters like SSA22 and the Spiderweb if we consider Lx>1e45 erg/s AGNs. The AGN fraction reaches 100% for galaxies with stellar mass >10^{10.5} Msun, and the average specific accretion rate increases toward the center of the structure, highlighting the significant role of dense environments in triggering SMBH growth at early cosmic times.In the same field, we detect significant extended X-ray emission (5.3 \sigma) around the central QSO, tracing hot gas out to ~30 kpc. Spectral modeling favors thermal emission from a proto-intracluster medium (proto-ICM) with T~1e7 K and halo mass ~1e13 Msun, among the earliest such detections at z>3. Alternative explanations, such as photoionization or inverse Compton emission, are strongly disfavored by the data.Together, these results support a scenario where high-z overdensities are not only key sites for accelerated SMBH growth, but also early cradles for the formation of extended hot gaseous halos, providing new insights into the interplay between AGN, environment, and baryon cycling in the early Universe.