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SUMMARY:Uncovering the physical origin of quasi-periodic oscillations from
  black hole X-ray binaries - Adam Ingram (Newcastle)
DTSTART:20250210T140000Z
DTEND:20250210T150000Z
UID:TALK227653@talks.cam.ac.uk
CONTACT:Thomas Jannaud
DESCRIPTION:Black hole X-ray binary systems consist of a black hole stripp
 ing material from its stellar companion to generate a large X-ray flux. Qu
 asi-periodic oscillations (QPOs) with a period in the range 0.1 to 10 seco
 nds are routinely observed in the X-ray flux from these systems. Despite b
 eing strong signals that have been detectable for around 40 years\, the ph
 ysical origin of these QPOs is still debated. The leading theory associate
 s the QPO with the relativistic effect of Lense-Thirring precession. This 
 model requires the black hole spin axis to be moderately misaligned with t
 he binary rotation axis\, in which case the frame dragging effect is expec
 ted to induce precession in the inner accretion flow. I will review the pr
 ecession model and the observational evidence in support of it\, as well a
 s discussing alternative theories. I will focus on two key predictions of 
 the precession model. First\, I will show that the iron line emitted from 
 the inner accretion disk oscillates between red and blue shifted with QPO 
 phase. Second\, I will describe our work to determine whether the X-ray po
 larization angle oscillates with QPO phase\, which has recently been made 
 possible by the launch of the Imaging X-ray Polarimetry Explorer (IXPE).
LOCATION:MR14 DAMTP and online
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