BLACK HOLE FEEDING AND FEEDBACK UNIFICATION

Introduction

BlackHoleWeather aims to unify the astrophysics of black-hole (BH) feeding and feedback within cosmic structures, in one comprehensive theory that leverages novel high-performance simulations, fundamental gas physics, and timely multiwavelength observations.

Cosmic Atmospheres

Most of the ordinary matter in the Universe is in the form of a tenuous gas which fills galaxies, groups, and clusters of galaxies (circumgalactic, intragroup, and intracluster medium). Such cosmic atmospheres are shaped by complex thermo-hydrodynamical processes - akin to Earth weather - with the central BH acting as a cosmic thermostat over scales of 9 orders of magnitude.

Current Discoveries

We have entered a Golden Age of multiphase gas detections continuously discovering:

• Ionized filaments (optical/UV)
• Neutral gas (IR/21cm)
• Molecular clouds (radio)

These components condense out of the hot X-ray halos or are ejected via BH feedback.

Key Challenges

We will tackle key challenges of modern astrophysics:

1. What is the origin and evolution of the macro precipitation?
2. How is the multiphase rain (or chaotic cold accretion) fed down through the BH horizon?
3. How is matter/energy re-ejected back by the BH and deposited via multiphase outflows, jets, and radiation?
4. What is the role of dust, turbulence, stars, and cosmic rays?
5. How does the self-regulated BH feeding-feedback loop shape galaxies throughout cosmic time?

Bridging Concepts

Bridging BH feeding and feedback via ab-initio, multi-scale (mpc to Mpc), and first-principle physics (magnetohydrodynamics, transport, chemistry, cosmology) is ambitious. Yet, it is a zero-to-one leap that current astrophysics must undertake, and whose public datasets will provide invaluable legacy for many astronomical communities.

Project Feasibility

BlackHoleWeather is a frontier yet feasible project, exploiting the timely convergence of our groundbreaking massively-parallel GPU code (GAMER2) and our ongoing multifrequency observing programs (e.g., Chandra, XMM, HST, ALMA, MUSE, JWST, SOFIA, MeerKAT).