| Name: | Soumen Mondal |
| Affiliation: | Jadavpur University, Kolkata |
| Conference ID: | ASI2025_372 |
| Title: | Observational imprints of accretion disk on observed gravitational wave data from LISA. |
| Authors: | Soumen Mondal and Prasad Basu |
| Authors Affiliation: | 1. Jadavpur University, Kolkata and 2. Cotton University, Guwahati, Assam |
| Mode of Presentation: | Oral |
| Abstract Category: | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract: | The proposed work aims to investigate and compare the detectability of the effect of massive accretion disks on the emitted gravitational wave from extreme/intermediate mass ratio inspirals for different types of accretion models of the disk, and thereby to check whether they are distinguishable in the LISA band. The hydrodynamic drag of the disk significantly modifies the motion of the companion as a result of the emitted wave changes in amplitude and phase. We found that these changes are detectable through the last few years of observation by LISA (in some cases as small as 6 months) for EMRIs residing within redshift z = 1 from the detector and for the accretion rate of the primary black hole of the order of one Eddington. We further identify the orbital parameters evolving under most general elliptical-orbits in the equatorial plane for which the magnitude of disc-torque is greater and that can potentially enhance detectability of accretion-disc effect on the observed GW-signal. Prioritizing such orbital-configuration, we obtain substantial impact on the dephasing and high signal-to-noise-ratio (SNR) in emitted signals. Employing a threshold-SNR ( > 8), we then identify the detectability trend of those systems in LISA-band. Moreover, the drag effect and hence the detectability of the emitted GW is also sensitive to the hydrodynamical model of the disc. Therefore, we vary the disc parameters, accretion rate, and duration of observation of E/IMRIs, and find that in comparison with other disc models, transonic solution offers relatively better observable signatures in detecting the gas-rich E/IMRI’s within the LISA band. Hence, the study will be important in understanding the orbital-evolution, predicting orbital-configuration and E/IMRI formation pathways, and finding detectability for such gas-rich E/IMRIs. Such observations will also help one to probe the nature of the accretion flow and verify various paradigms of accretion physics.
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