SS Weekly Highlight

Title: New Publication – Shaken Snow Globes: Kinematic Tracers of the Multiphase Condensation Cascade in Massive Galaxies — Pasquale Temi (Code SSA)

With this work we propose a novel method to constrain turbulence and bulk motions in massive galaxies, groups and clusters, exploring both simulations and observations. As emerged in the recent picture of the top-down multiphase condensation, the hot gaseous halos are tightly linked to all other phases in terms of cospatiality and thermodynamics. While hot halos (107 K) are perturbed by subsonic turbulence, warm (104 K) ionized and neutral filaments condense out of the turbulent eddies. The peaks condense into cold molecular clouds (< 100 K) raining in the core via chaotic cold accretion (CCA). We show all phases are tightly linked via the ensemble (wide-aperture) velocity dispersion along the line of sight. The correlation arises in complementary long-term AGN feedback simulations and high-resolution CCA runs, and is corroborated by the combined Hitomi and new IFU measurements in Perseus cluster. The ensemble multiphase gas distributions are characterized by substantial spectral line broadening (100-200 km/s) with mild line shift. On the other hand, pencil- beam detections sample the small-scale clouds displaying smaller broadening and significant line shift up to several 100 km/s, with increased scatter due to the turbulence intermittency. We present new ensemble sigmav of the warm Halpha+[NII] gas in 72 observed cluster/group cores: the constraints are consistent with the simulations and can be used as robust proxies for the turbulent velocities, in particular for the challenging hot plasma (otherwise requiring extremely long X-ray exposures). We show the physically motivated criterion C = tcool/teddy ~ 1 best traces the condensation extent region and presence of multiphase gas in observed clusters/groups. The ensemble method can be applied to many available datasets and can substantially advance our understanding of multiphase halos in light of the next-generation multi-wavelength missions. 
Important Note: This work, just published in the Astrophysical Journal, is in collaboration with Dr. M. Gaspari at Princeton University and other members of the international scientific community. The objectives are aligned with the on-going development of the Arcus X-Ray Grating Spectrometer Mission (Phase-A Midex-Explorer). This investigation provides constraints on the fundamental interaction between massive black holes and galaxies via comparison of observational data with simulations. High-resolution 3D hydro- dynamical simulations are used to improve the understanding of the AGN feedback phenomenon by studying in great detail the single sub process. 
This project made extensive use of the NASA Advanced Supercomputing (NAS) resources at NASA/Ames (Program SMD-16-7320, SMD-16-7321, SMD-16-7305).


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