Winds and Jets

This concept illustration showcases a supermassive black hole surrounded by a luminous accretion disk. At the center is a pure black void, symbolizing the black hole itself. Surrounding it is a bright accretion disk that glows in intense hues of yellow, orange, and red, indicating superheated gas and matter swirling at immense speeds. The disk appears smooth and fluid, with darker orange and brown shades radiating outward to depict cooler regions further from the black hole. The background is a muted gradient of dark tones, drawing attention to the glowing accretion disk and the profound blackness of the central void.
A concept illustration of a supermassive black hole with millions to billions times the mass of our sun (Credits: NASA/JPL-Caltech)
An artist’s conception of a black hole disk wind. Image credit: NASA/Chandra.

Black holes eat like the Cookie Monster – some gas is ingested and contributes to the mass of the black hole, but even more appears to be lost before reaching the event horizon.  Despite the ubiquity of these flows, we do not know the answers to the most basic questions.  Does the mass outflow rate scale with the mass inflow rate?  Does the outflow velocity scale with the mass inflow rate?  Are accretion-driven outflows pushed like sailboats, or are they shot like cannonballs?  We are actively working on these questions, and many others.

Accretion onto black holes and neutron stars causes the infalling gas to heat-up and radiate.  This X-ray glow is how we find and identify new sources.  But radiation is not the only form of feedback into local host environments.  Accretion also results in wide-angle disk winds, and collimated, relativistic jets of material.  Exactly how disks and compact objects drive these flows of matter and energy (is black hole spin involved?), and exactly how much mass and power are transmitted, are exciting questions that must be answered to understand the co-evolution of black holes and host galaxies.  The best spectra are revealing new aspects of winds, and it appears that wind and jet modes are anti-correlated (if imperfectly).   Coordinated studies of accretion and ejection hold potential.  The ultimate goal is a complete description of radiation, winds, and jets, as a function of black hole mass, spin, and accretion rate; we have taken an initial step toward that goal.