POSITIVE AGN FEEDBACK AT HUNDREDS OF KPC SCALES IN A PROTOCLUSTER AT Z=1.7

<p>High-z protoclusters are ideal laboratories to investigate the relation between AGN feedback, ICM heating, and galaxy evolution at the peak formation epoch of galaxy clusters.</p> <p>We will present multi-band observations of a z=1.7 protocluster assembling around an FRII radio-galaxy that provide strong insight into the above processes.</p> <p>A deep (0.5 Ms) Chandra look at the system revealed several spots of diffuse X-ray emission, the most prominent of which (bubble A) overlaps with the Eastern radio lobe. We will discuss thermal emission or Inverse Compton scattering of CMB photons (IC-CMB) as viable mechanisms to produce the observed X-ray spots, and present new LOFAR observations suggesting that bubble A is due to IC-CMB. In addition, the expanding plasma in the Western radio-jet and lobe likely shock-heats pockets of gas in the inhomogeneous ambient medium to the ~keV temperature observed in the other X-ray spots.</p> <p>Bubble A is surrounded by the four galaxies with the largest specific star formation rates among all protocluster members. This calls for remarkable, positive AGN feedback produced hundreds of kpc away from the FRII nucleus by the expanding bubble.</p> <p>We will discuss future observations of the system and finally present prospects for future population studies of similar, high-z protoclusters with the Survey and Time-domain Astrophysical Research eXplorer (STAR-X), a Medium Explorer mission selected by NASA for Phase A study.</p> <p>&nbsp;</p>