BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Mapping accreting black holes using X-ray variability - Adam Ingra
 m (Oxford)
DTSTART:20191017T150000Z
DTEND:20191017T160000Z
UID:TALK131431@talks.cam.ac.uk
CONTACT:Dominic Walton
DESCRIPTION:Stellar-mass black holes accreting gas from a binary partner (
 X-ray binaries) and supermassive black holes accreting gas from their host
  galaxy (active galactic nuclei) can emit a huge X-ray flux from the vicin
 ity of the black hole event horizon. This can be exploited to probe the st
 rong field regime of General Relativity and measure the properties of the 
 black hole: its mass and angular momentum. For all but two objects in the 
 Universe\, the vicinity of the accreting BH is far too small to directly i
 mage\, necessitating the use of mapping techniques that exploit rapid X-ra
 y variability. I will talk about two such techniques that utilise the rela
 tivistically broadened iron emission line routinely observed in the X-ray 
 spectrum that results from continuum photons reflecting from the accretion
  disk. First I will talk about reverberation mapping\, which exploits the 
 light-crossing delay between directly observed and reflected photons. I wi
 ll present our mass measurement of the black hole in Cygnus X-1 - the firs
 t X-ray reverberation mass measurement of a stellar-mass black hole. I wil
 l then talk about phase-resolved spectroscopy of quasi-periodic oscillatio
 ns (QPOs) in X-ray binary systems. I will present our discovery of a ~4 s 
 quasi-periodic variation of the iron line centroid energy in H 1743-322\, 
 and our detailed `tomographic' modelling of the QPO phase dependent reflec
 tion spectrum of MAXI J1535-571. Both analyses provide strong evidence tha
 t the QPO results from nodal precession of the inner accretion flow\, alth
 ough it is unclear whether or not this precession is specifically relativi
 stic Lense-Thirring precession.
LOCATION:Sackler Lecture Theatre\, IoA (tea at 3:30 pm)
END:VEVENT
END:VCALENDAR