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Enhanced Extreme Mass Ratio Inspiral Rates and Intermediate Mass Black Holes.
Ismail Qunbar1, Nicholas C Stone1
1Racah Institute of Physics, <a href="https://ror.org/03qxff017">The Hebrew University</a>, 91904 Jerusalem, Israel.
Physical Review Letters
|October 18, 2024
Summary
Extreme mass ratio inspirals (EMRIs) may not always be distinct from direct plunges. A new "cliffhanger" EMRI channel emerges for intermediate-mass black holes, potentially increasing event rates.
Area of Science:
- Astrophysics
- Gravitational Wave Astronomy
- Black Hole Physics
Background:
- Extreme mass ratio inspirals (EMRIs) involve stellar-mass objects orbiting massive black holes, emitting gravitational waves (GWs).
- EMRIs are crucial for mapping spacetime with GW detectors like LISA, but their event rates and characteristics are uncertain.
- A key uncertainty is distinguishing true EMRIs from direct plunges, impacting detection rates.
Purpose of the Study:
- To investigate the relationship between EMRIs and plunges for intermediate-mass black holes (IMBHs).
- To identify novel EMRI formation channels and their impact on event rates.
Main Methods:
- Analysis of gravitational wave driven inspirals.
- Modeling of object trajectories around IMBHs (M≲10⁵M⊙).
- Investigating the transition probability from plunges to EMRIs.
Main Results:
- The traditional EMRI/plunge dichotomy breaks down for IMBHs.
- A new "cliffhanger" EMRI channel emerges where plunges transition into EMRIs.
- This channel is more probable for larger compact objects and can significantly increase volumetric EMRI rates.
Conclusions:
- Cliffhanger EMRIs offer a new pathway for EMRI detection.
- The prevalence of IMBHs in dwarf galactic nuclei could dramatically increase observable EMRI rates.
- This finding has significant implications for future GW astronomy missions like LISA.
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