{"@context":"https://schema.org","@type":"ScholarlyArticle","headline":"Gravitational Waves from Massive Black Hole Mergers in ASTRID: Predictions for LISA","author":[{"@type":"Person","name":"Bonny Y. 玥 Wang 汪"},{"@type":"Person","name":"Yihao 亦豪 Zhou 周"},{"@type":"Person","name":"William Chen"},{"@type":"Person","name":"Nianyi Chen"},{"@type":"Person","name":"Tiziana Di Matteo"},{"@type":"Person","name":"Rupert Croft"},{"@type":"Person","name":"Simeon Bird"},{"@type":"Person","name":"Yueying Ni"}],"datePublished":"2025","isPartOf":{"@type":"Periodical","name":"The Astrophysical Journal"},"identifier":"https://doi.org/10.3847/1538-4357/ae073e","description":"Abstract\n \n We use the ASTRID cosmological simulation to forecast massive black hole (MBH) mergers detectable by Laser Interferometer Space Antenna (LISA) down to\n z\n = 0. ASTRID directly models MBH dynamical friction, allowing a realistic tracking of their trajectory. It also incorporates relatively low-mass MBH seeds down to 5 × 10\n 4\n M\n ⊙\n , providing a more complete picture of LISA MBH mergers. We find that LISA MBH mergers initially have high eccentricities, peaking around\n e\n 0\n = 0.8 across all redshifts. Accounting for this boosts the event rate from 5.6 yr\n −1\n (if circular orbits are assumed) to 10.5 yr\n −1\n . This enhancement is largely due to additional inspiral sources that will coalesce after LISA’s observation, which constitute 46% of detected events. This underscores the importance of LISA’s sensitivity to the early inspiral phase, especially for eccentric binaries that emit gravitational waves across a wider frequency band. Most LISA events in ASTRID arise from\n M\n BH\n ∼ 10\n 5−6\n M\n ⊙\n , low-redshift (\n z\n < 2) and low-mass-ratio (\n q\n ∼ 0.01–0.1) mergers. Accounting for eccentricity broadens the detectable MBH mass range up to 10\n 9\n M\n ⊙\n and shifts the peak of detectable mergers to a lower redshift\n z\n peak\n = 0.8. This implies that the most massive LISA events may also be PTA sources. We predict LISA events to be in various galaxy environments, including many low-mass satellite galaxies. The electromagnetic (EM) counterparts of most LISA sources have active galactic nuclei (AGN) luminosities\n L\n bol\n > 10\n 42\n erg s\n −1\n , albeit only 1% with >10\n 44\n erg s\n −1\n . The brightest AGN are those associated with the rare LISA/PTA events with\n M\n BH\n > 10\n 8\n M\n ⊙\n .\n ","url":"https://innscience.ca/en/community/literature/59d595c9-caaf-415a-a425-103fbc572353"}