Galaxy formation, ICM heating and AGN feedback: the turbulent youth of a proto-cluster at z=1.7
Abstract
I present the physical properties of a large-scale structure at z=1.7 that is populated by star-forming galaxies and is assembling around a powerful FRII.
Based on ALMA observations of the CO(2-1) transition, we recently discovered three new gas-rich galaxies, in addition to a large molecular gas reservoir (M_H2~2 x 10^11 M_sun) around the FRII host galaxy.
We also detect 3 mm continuum emission in the core and in one hotspot of the radio galaxy. Under simple assumptions, we show that the system will evolve into a ≳ 10^14 M_sun cluster at z=0 and that the FRII is the likely progenitor of the future BCG.
Extended X-ray emission has been detected around the FRII. Remarkably, four of the protocluster members lie in an arc-like shape around the main X-ray extended emission. We propose that such emission originates from an expanding bubble of gas shock heated by the FRII jet, that is promoting the star formation on nearby galaxies by compression of their ISM. If confirmed, this would be the first evidence of positive AGN feedback on multiple galaxies on hundreds-kpc scales. I also present new LOFAR (150 MHz) and JVLA (1.4 GHz) observations of the FRII, which reveal extended radio emission around its lobes, likely linked to the diffuse X-rays. Exploiting the JVLA and LOFAR data we built the spectral index map that reveals signatures of re-acceleration of the plasma in the outskirts of the lobes, possibly induced by interactions with the ICM.
- Publication:
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Galaxy Cluster Formation II
- Pub Date:
- June 2021
- DOI:
- 10.5281/zenodo.4984781
- Bibcode:
- 2021gcf2.confE..35D
- Keywords:
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- Zenodo community gcf2021;
- Galaxy Cluster Formation