PAPER / ARXIV:2609.07176
Anson Chen , Jun Zhang
RESUMO
Stellar-mass binary black holes sweep through the millihertz, decihertz, and kilohertz gravitational-wave bands before merger, making them prime targets for multiband observations. We forecast their detection rates and parameter-estimation precision for networks combining the millihertz observatories LISA, Taiji, and TianQin; the decihertz concepts LGWA, AMIGO, and AMIGO-5; and the ground-based LVK and Cosmic Explorer. Using the binary-black-hole mass and redshift distributions inferred from GWTC-4, we first estimate the single-band yields and then account explicitly for detector lifetimes and relative mission start times when calculating multiband rates. For a signal-to-noise-ratio threshold of 8, the LISA--Taiji--TianQin network is expected to detect $53.6^{+19.7}_{-14.1}$ systems in the millihertz band, while the largest three-band yield is $23.5^{+8.7}_{-6.2}$ events for LISA--Taiji--TianQin combined with LGWA. The yield is maximized when the decihertz observation begins approximately $0$--$3\,{\rm yr}$ after the millihertz mission. Ground-informed subthreshold searches with a threshold of 5 increase the multiband yields by a factor of approximately $4$--$5$, reaching $125.1^{+46.1}_{-32.9}$ events for the same network. Fisher-matrix forecasts for a GW150914-like source show that decihertz observations provide the dominant improvement in most multiband parameter constraints, whereas millihertz data primarily sharpen the detector-frame chirp mass and sky localization. Combining the three bands improves the chirp-mass precision by orders of magnitude relative to ground-based observations alone and can reduce the localization area and coalescence-time uncertainty substantially. These results demonstrate that coordinated mission scheduling and targeted subthreshold searches are essential for realizing the scientific potential of stellar-mass multiband gravitational-wave astronomy.
NO MESMO MAPA