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SUMMARY:The Taxonomy of Spin Precession in Binary Black Holes - Daria Gang
 ardt\, University of Birmingham
DTSTART:20221007T120000Z
DTEND:20221007T130000Z
UID:TALK179087@talks.cam.ac.uk
CONTACT:Isobel Romero-Shaw
DESCRIPTION:\nHow do black holes spin?\nUnlike in Newtonian gravity\, if t
 wo black holes are gravitationally bound\, then their spins will interact 
 with each other\, and notably the orbital angular momentum. This causes th
 e orbital plane to tilt\, leading to a modulation of the phase and amplitu
 de of the gravitational waves emitted by the binary. These modulations are
  complex combinations of the individual spin parameters\, motivating gravi
 tational wave measurements to be reported using two effective parameters\,
  $\\chi_{\\rm eff}$ and $\\chi_{P}$. These parameters are useful from a wa
 veform perspective\, but can obscure the rich spin dynamics of the two bla
 ck holes during the inspiral.\nIn this talk\, I will present an alternativ
 e approach to spin precession classification\, through the introduction of
  five phenomenological parameters. These parameters disentangle the motion
  of the orbital angular momentum into its azimuthal motion (precession)\, 
 and its polar motion (nutation). This complimentary method allows us to ca
 pture some of the key features of the spin precession taxonomy\, thus more
  closely following the spin dynamics of the black hole binary. I will also
  show a follow up study where we constrain the five parameters in the grav
 itational wave catalogs using the LIGO-Virgo-KAGRA (LVK) parameter estimat
 ion samples. In agreement with current population constraints\, the result
 s find evidence of precession in the gravitational wave events. While cons
 traints on the orbital angular momentum nutation of individual events in t
 he catalogs are weak\,  with future LVK sensitivities the detection of nut
 ation becomes a possibility.
LOCATION:Potter room/Zoom
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