Reverberation mapping

Summary• Large amounts of gas are seen in X-ray band and this gas mustexist close to black hole (illuminated by X-rays that come fromvery close to BH and X-ray spectral signatures vary fast,meaning they come from a very small region)• High velocities detected for X-ray absorbing/emitting gas• In principle can learn about effects very near BH, such aslooking for GR distortions of emission and absorption lineprofiles• Feedback from nucleus to the host galaxy can be studied bylooking at velocities in to /out from nucleus