Parameter estimation for space-based gravitational wave detectors with\n ringdown signals

Abstract

Unlike ground-based gravitational wave detectors, space-based gravitational\nwave detectors can detect the ringdown signals from massive black hole mergers\nwith large signal-to-noise ratios, help to localize sources and extract their\nparameters. To reduce the computation time in the Fisher information matrix\nanalysis, we derive the analytical formulas of frequency-domain ringdown\nsignals for both heliocentric and geocentric detectors by considering the\neffects of the harmonic phases, the rotation period of the geocentric detector,\nand the detector's arm length. We explore median errors of the parameter\nestimation and source localization with ringdown signals from binaries with\ndifferent masses and different redshifts. Using a binary source with the total\nmass $M=10^7\\ M_\\odot$ at the redshift $z=1$, we analyze the dependence of\nthese errors on the sky position. We find that the network of space-based\ngravitational wave detectors can significantly improve the source localization\nat the ringdown stage. The results of the Fisher matrix approximation are also\nchecked by Bayesian inference method.\n