{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9296f74c4b119eb3b6572b79ca9ec0d4e2f17810cdb01dd56851c3cd0780d2c8","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["99ac7eed9724824e1ab283652b4cb9dc7351c964ac390dbd8517403c1552cd15","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"d8e61bfa16c55f0db6edeec4e9f70058825387491133b9817f9bbc57013bf0bf","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"astro.galaxy-quenching.cooling-flow","kind":"phenomenon","literature_status":"partially-resolved","n":"2","parents":[],"plain":"Gas at the centers of galaxy clusters radiates away its heat in less than a billion years, yet it forms stars at only a few percent of the expected rate. Jets from the central black hole carry enough energy, but how that energy spreads evenly through the gas is not known.","posed_since":"","precise":"In cool-core clusters the central gas has cooling time $t_{\\mathrm{cool}}<1\\ \\mathrm{Gyr}$ within $\\sim 100\\ \\mathrm{kpc}$, while star formation rates are $\\sim 1\\text{-}10\\%$ of classical cooling-flow rates of $10^2\\text{-}10^3\\ M_{\\mathrm{sun}}/\\mathrm{yr}$. Determine how jet mechanical power $P_{\\mathrm{jet}}\\sim 10^{44}\\text{-}10^{46}\\ \\mathrm{erg/s}$ is converted to heat nearly isotropically: weak shocks, sound waves, turbulent dissipation, cosmic-ray heating, or turbulent mixing. The answer is the heating rate per channel versus radius matched to the cooling rate.","problem_ref":"99ac7eed9724824e1ab283652b4cb9dc7351c964ac390dbd8517403c1552cd15","references":"","settled_by":"High-resolution X-ray spectroscopy of gas velocities and temperatures in cluster cores (XRISM and successors) combined with simulations reproducing the measured velocity structure and the heating balance.","status_note":"Jet cavity energetics match the cooling luminosity; Hitomi in 2016 measured a line-of-sight velocity dispersion of about $1.6x10^{7}\\,\\mathrm{cm}/\\mathrm{s}$ in the Perseus core, and XRISM has been measuring cluster core velocities since 2024.","title":"How do black hole jets keep cluster cores from cooling?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0cdd66fa275b7863bfab476620baee317e5f9bffdc6f48161fdfc6eaed40a687","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"cacc8f8d077b3902e7c54a918b4c8fd64144819d15ad33b684dc661b86c544c0","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"2QBXU8VEK9_uFGhg0dEDq3iVvYGd0iNOzU2lbGll-5kFhWy_qFJyQ72dfW1T6R9PKi9Atl0nm7bwfREI-cbDDg"},"schema":"pubphys.envelope/1"},"record_hash":"0cdd66fa275b7863bfab476620baee317e5f9bffdc6f48161fdfc6eaed40a687","leaf_index":2362}