Extreme Mass Ratio Inspirals triggered by Massive Black Hole Binaries: from Relativistic Dynamics to Cosmological Rates

Abstract

Extreme mass ratio inspirals (EMRIs) are compact binary systems characterized by a mass-ratio $q=m/M$ in the range $10^{-9}-10^{-4}$ and represent primary gravitational wave (GW) sources for the forthcoming Laser Interferometer Space Antenna (LISA). While their standard formation channel involves relaxation processes deflecting compact objects on very low angular momentum orbits around the central massive black hole, a number of alternative formation channels has been proposed, including binary tidal break-up, migration in accretion disks and secular and chaotic dynamics around a massive black hole binary (MBHB). In this work, we take an extensive closer look at this latter scenario, investigating how EMRIs can be triggered by a MBHBs, formed in the aftermath of galaxy mergers. By employing a suite of relativistic three-body simulations, we evaluate the efficiency of EMRI formation for different parameters of the MBHB, assessing the importance of both secular and chaotic dynamics. By modelling the distribution of compact objects in galaxy nuclei, we estimate the resulting EMRI formation rate, finding that EMRI are produced in a sharp burst, with peak rates that are 10-100 times higher than the standard two-body relaxation channel, lasting for 10${}^6$--10${}^8$ years. By coupling our results with an estimate of the cosmic MBHB merger rate, we finally forecast that LISA could observe $\mathcal{O}(10)$ EMRIs per year formed by this channel.

arXiv comment18 pages, 15 figures, accepted for publication in MNRAS

References in corpus (39)

• A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• A Relationship Between Nuclear Black Hole Mass and Galaxy Velocity Dispersion
• The Eccentric Kozai-Lidov Effect and Its Applications
• Science with the space-based interferometer LISA. V: Extreme mass-ratio inspirals
• Galaxy formation in the Planck Cosmology - I. Matching the observed evolution of star formation rates, colours and stellar masses
• LISA Capture Sources: Approximate Waveforms, Signal-to-Noise Ratios, and Parameter Estimation Accuracy
• Intermediate and Extreme Mass-Ratio Inspirals -- Astrophysics, Science Applications and Detection using LISA
• The dynamical evolution of massive black hole binaries - I. Hardening in a fixed stellar background
• Secular Dynamics in Hierarchical Three-Body Systems
• Starbursts near supermassive black holes: young stars in the Galactic Center, and gravitational waves in LISA band
• The Kozai Mechanism and the Evolution of Binary Supermassive Black Holes
• Event rate estimates for LISA extreme mass ratio capture sources
• The evolution of massive black holes and their spins in their galactic hosts
• Four-Body Effects in Globular Cluster Black Hole Coalescence
• Stellar remnants in galactic nuclei: mass segregation
• Relativistic Dynamics and Extreme Mass Ratio Inspirals
• Interaction of massive black hole binaries with their stellar environment: I. Ejection of hypervelocity stars
• The imprint of massive black hole formation models on the LISA data stream
• The orbital statistics of stellar inspiral and relaxation near a massive black hole: characterizing gravitational wave sources
• Tidal stellar disruptions by massive black hole pairs: II. Decaying binaries
• Scattering experiments meet N-body I: a practical recipe for the evolution of massive black hole binaries in stellar environments
• Enhanced tidal disruption rates from massive black hole binaries
• Binary Encounters With Supermassive Black Holes: Zero-Eccentricity LISA Events
• Formation Rate of Extreme Mass Ratio Inspirals in Active Galactic Nuclei
• Probing the existence of ultralight bosons with a single gravitational-wave measurement
• On strong mass segregation around a massive black hole: Implications for lower-frequency gravitational-wave astrophysics
• Gravitational wave background from extreme mass ratio inspirals
• Post-Newtonian Evolution of Massive Black Hole Triplets in Galactic Nuclei: I. Numerical Implementation and Tests
• From galactic nuclei to the halo outskirts: tracing supermassive black holes across cosmic history and environments
• Gravitational wave cosmology with extreme mass-ratio inspirals
• The role of the supermassive black hole spin in the estimation of the EMRI event rate
• Gravitational wave sources in the era of multi-frequency gravitational wave astronomy
• Gravitational waves from extreme mass ratio inspirals: Challenges in mapping the spacetime of massive, compact objects
• Exploring the local black hole mass function below $10^6$ solar masses
• Tidal Disruption of Stellar Objects by Hard Supermassive Black Hole Binaries
• Tidal Disruption Events by a Massive Black Hole Binary
• Is there an intermediate massive black hole in the Galactic center: Imprints on the stellar tidal-disruption rate
• $r$-process nucleosynthesis in the early Universe through fast mergers of compact binaries in triple systems