Hello, Cosmolunchers!
This week we have two presentations! Makana will give us a preview of his upcoming paper. The abstract can be found below. If there is remaining time, I will present yet another hubble tension paper, this one looking into the effects the small sample volume of supernovae measurements might have on their results.
Find the paper here:
https://arxiv.org/pdf/2207.02373.pdf
Makana’s abstract:
Extreme mass ratio inspirals (EMRIs) - systems with a compact object orbiting a much more massive (e.g., galactic center) black hole - are of interest both as a new probe of the environments of galactic nuclei, and their waveforms are a precision test of the Kerr metric. This work focuses on the effects of an external perturbation due to the third body around an EMRI system. Thisperturbationwill affects the orbit most significantly when the inner body crosses a resonance with the outer body and results in a change of the conserved quantities (energy, angular momentum, and Carterconstant)or equivalently of the actions, which results in a subsequent phase shift of the waveform that builds up over time. We present a general method for calculating the changes in action during resonance crossing, valid for generic orbits in the Kerr spacetime. We show that these changes are related to the gravitational waveforms emitted by the two bodies (quantified by the amplitudes of the Weylscalar ψ4 at the horizon and at ∞) at the frequency corresponding to the resonance. This allows us to compute changes in the action variables for each body without directly computing the explicit metric perturbations. Therefore we can carry out the computation by calling an existing black hole perturbation theory code. We show that our calculation can probe resonant interactions in both the static and dynamical limits. We plan to use this technique for future investigations of third-body effects in EMRIs and their potential impact on waveforms for LISA.
Cosmolunch will be a hybrid in Price Place. Connect via zoom here:https://osu.zoom.us/j/92974075784pwd=QVZKWDB5amZyTHU5aHJxbndDbFQ0UT09
Cosmolunch website: https://sites.google.com/site/ccappcosmolunch/
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